The purpose of this project is to design and mass-produce kits for a floating tiny house that can sail. It combines high-tech modeling and fabrication and low-tech assembly that can be carried out DIY-style on a riverbank or a beach. This boat is a four-bedroom with a kitchen, a bathroom/sauna, a dining room and a living room. The deck is big enough to throw dance parties. It can be used as a river boat, a canal boat or even a beach house. It's rugged and stable enough to take out on the ocean. Kits will start at around $50k (USD). The design has been tested in simulation and prototype; full-scale production will begin next year.

Sunday, June 16, 2019

Dismasting Made Easy

You are sailing along on a passage, on autopilot, the radar set up to wake up and do a sweep every 10 minutes or so and sound an alarm if it detects a collision course, with the entire crew (which could be just me and the ship’s cat) down below doing whatever people and cats do when they aren’t sailing. Then a squall kicks up, or a waterspout (a sort of water-borne tornado), or you royally screwed up and plotted a course that takes you under a bridge that’s too low. Suddenly, you find yourself minus the masts. This can be very dramatic, or not, depending on how the boat is designed. And since Quidnon is primarily a houseboat (that sails), drama is specifically what we don’t want.

There are a few different solutions for installing masts. First, there are deck-stepped masts. They are installed using a crane which lifts the mast up by a point somewhere above its center of mass so that it hangs down more or less straight. The heel of the mast is placed where intended, and then the standing rigging is hooked up, which consists of wire rope and turnbuckles with which to tension it. Standing rigging consists of a forestay, a backstay and some number of shrouds that go off to the sides of the deck and may go around spreaders. (By the way, spreaders are a terrible idea, unless you like your deck to be covered in guano, because they provide nice perches for sea birds.) Where there isn’t room for a backstay (such as with a mizzen mast on a ketch or a yawl) there are often running stays which are clipped on and tensioned as needed. There may also be baby stays (miniature forestays) and triatics that tie the tops of masts together.

Second, there are the keel-stepped masts. These go through a reinforced hole in the deck (which will at some point leak water into the cabin) and the heel of the mast is stepped in a bracket that’s bolted to the top of the keel. The nice thing about keel-stepped masts is that they don’t flop down instanter whenever some bit of standing rigging fails. On a deck-stepped mast, if the forestay fails, then the mast flops down on the cockpit, braining whoever happens to be in it; if the backstay fails, then it flops forward. The standard material for standing rigging is stainless steel wire rope, used because it’s less stretchy than regular galvanized wire rope, and stainless steel fittings to attach it (turnbuckles, shackles, etc.) The nasty thing about stainless (other than its exorbitant cost) is that unlike regular mild steel it tends to develop invisible microfractures over time, then fail catastrophically.

When standing rigging on a keel-stepped mast fails, it may soldier on for quite a while, enlarging its hole in the deck as it swings about. When it finally fails, it is likely to snap off at the deck, since that’s the point of greatest stress. Either way, what you end up is a rather large stick flailing about uncontrollably, tugging at a mad tangle of rope and cable that gets caught up on everything it possibly can, trying to rip it off. At that point, people generally rush about the deck with bolt cutters, tying to snap every bit of line and cable that connects the mast to the boat, in order to set the mast on a journey of is own, down to the murky depths.

There are also unstayed masts which have no standing rigging at all. These are always keel-stepped, since if they were deck-stepped they would simply fall over. They have to be quite a bit stronger than stayed masts, since they rather than the standing rigging have to withstand the press of the sails. To keep their weight reasonable, they are usually tapered. Mast-stepping techniques are a bit like the techniques for holding up your pants: deck-stepped masts with standing rigging are like wearing suspenders, keel-stepped masts without standing rigging are like wearing a belt, and keel-stepped masts with standing rigging are like wearing both. Which of these makes for the most exciting strip-tease (dismasting, that is) is, I suppose, a matter of taste.

Keel-stepped masts have some disadvantages. I already mentioned the almost inevitable leaks through the hole in the deck. There is also the problem of sagging, especially if there is standing rigging: the mast pushes down on the center of the boat while the forestay and the backstay pull up on the bow and the transom. Over time, this causes the hull to acquire a slight banana shape. In turn, this causes bilge water to pool around the mast heel. The bracket the mast heel rests in is usually made of mild steel while the mast itself is usually aluminum, and the two undergo a galvanic reaction: the bracket rusts while the mast heel rots away. If the forestay or the backstay and the mast heel both fail, then you have the bottom end of the mast ripping through the cabin.

Finally, keel-stepped masts chill the cabin. Aluminum is an excellent conductor of heat, and having an aluminum stick part of which is inside the cabin and part of it outside sucks heat out of the cabin most efficiently. Wrapping it in layers of radiant barrier and fabric helps somewhat, but it’s much more pleasant not to have it there in the first place.

Mounting the masts on Quidnon presents a rather interesting design problem. Since there is no keel, keel-stepped is not an option. Since there is a requirement that the masts be easy to raise and lower without recourse to a crane, deck-stepped is not an option either. And since the sails are Junk rigs, which rise above the top of the mast when fully raised, having forestays and backstays is not an option either. Lastly, Quidnon is a houseboat, and whereas with a sailboat built for sport or ostentation it is acceptable to respond to a dismasting at sea by declaring it a total loss, abandoning ship and setting off in a life raft expecting to be rescued (or not, as the case may be) with Quidnon the loss of two large vertical sticks should not compromise its ability to serve as a floating domicile, albeit one now temporarily deprived of its ability to sail. It is thus a requirement that a dismasting does not compromise the integrity of the hull.

Since Quidnons will spend most of the time sitting at anchor or at the dock and only once in a while undertake a journey under sail, perhaps as a seasonal migration to shift berth between summer and winter quarters, perhaps to relocate to a different permanent location as conditions warrant, most of the time the masts can be kept lowered and the sails bundled up into their sail covers and stowed on deck. Thus, it is yet another requirement that the masts be unobtrusive when lowered.

This mast tabernacle design has gone through a number of changes but is now in a state that fulfills all of these requirements. Here are the plan and elevation views with the masts lowered and resting on the deck arches. Note that with the masts lowered Quidnon is not any longer overall than with the masts raised. This is important, because marinas charge slip fees by overall length, which includes any overhanging objects. Quidnon fits into exactly 36 feet, makes full use of the width of a marina slip with its 16-foot beam, and provides very close to 36 by 16 feet, or 576 square feet of interior living space with ample headroom.



There are three deck arches, and they serve a large number of purposes:

• They provide support for the masts when they are lowered

• They allow the masts to slide back and forth, back before being raised, forth after being lowered, on rollers positioned close to the centerline

• The second and third deck arches have T-track with sheet blocks running along their tops

• They provide cabin ventilation through openings in their front and back, blowing air into the cabin and sucking it out again

• They serve as a frame for either a canvas cover or shrink-wrap for winterizing the boat

• The second deck arch has a block and tackle for loading and unloading the boat through the deck hatch

• The third deck arch has a block and tackle for installing and removing the outboard engine that lives in the engine well

• The first deck arch provides a mounting place for the radar’s radome

• The deck arches provide places to hang hammocks or swings, to mount solar panels, etc.

In short, deck arches are fantastically versatile and useful, which is why Quidnon has not one, not two, but three of them.

Here is the elevation view of Quidnon viewed from the transom, with the masts lowered and sitting side by side on the deck arches.



Note the various dimensions. The hull is basically an 8-foot by 16-foot by 36-foot box. It is 1 plywood sheet tall, 2 plywood sheets wide and 4.5 plywood sheets long, arranged in a pattern that generates minimum scrap. There is 5½ feet of vertical clearance below the deck arches, and the taller people will have to stoop to walk under them. On the other hand, they are low enough for most adults to be able to work with them, and with the masts that rest on them, without having to resort to footstools or stepladders. It’s a compromise. The bridge clearance with masts lowered is 14 feet, and most fixed bridges on navigable waterways provide at least that much.

Now let’s go through the details of the mast stepping arrangement. Here is a drawing of a mast (in this case, the mainmast, but the differences are subtle). There are three main elements:

• The mast itself, which includes a masthead fitting at the top and a heel plug at the bottom. The mast is made up of either a single 36-foot length of 6-inch Schedule 40 aluminum pipe or (since 6-inch Schedule 40 pipe is most easily obtained in 20-foot sections) two pieces joined together using a short length of inner tube and some epoxy. (Welding the two pieces together is also possible, but making structurally sound welds in aluminum is quite an art while the epoxied joint is dead simple and relatively idiot-proof.)

• The tabernacle, which is made of galvanized mild steel and can be fabricated using an oxyacetylene cutting torch, a stick welder and a grinder (although a plasma cutter and a TIG welder would work even better) and includes a mast hinge at the top and a pressure plate at the bottom.

• The mast trunk, which is a cylindrical piece of lumber that runs from the bottom of the hull through a hole in the deck and protrudes 3 feet above it. The mast tabernacle fits over it.



The set-up is basically of a deck-stepped mast, because the pressure plate rests on the deck. But the mast doesn’t topple without standing rigging because the tabernacle sits over the mast trunk, which is constrained to being vertical. It goes through a hole in the deck, where it is secured using a pin and caulked into place, so that there are no deck leaks. The heel of the mast trunk sits in a cup that is fastened to the bottom. There is an air gap between the bottom of the mast trunk and the hull bottom of the cup, so that the mast trunk does not exert any vertical force on the hull bottom as the hull flexes. It does exert horizontal forces, which the bottom can readily withstand.

Taking each of these elements in turn. The masthead fitting is a simple affair; like all the other elements except the mast and the mast trunk, it is made of galvanized mild steel. It consists of a short piece of pipe that fits over the masthead welded to an oval plate with two gussets that face fore and aft. The gussets have holes which take the pin of a D-shackle. This shackle is then used to attach, using teardrop-shaped thimbles, all of the needed lines: the halyard, two topping lifts and four running stays (of which more later).

Masthead fittings generally include some number of brackets for mounting a VHF antenna, an illuminated wind direction indicator and a wind instrument that measures wind speed and direction. It is also a good place to mount a 3/4/5G router; at some 50 feet above water it will “see” towers quite far over the horizon, making it possible to have internet and VOIP access even when sailing outside of sight of land.

All of these masthead instruments generate quite a mess of wiring which has to be sent down the mast and into the hull. To keep it banging around inside the mast, keeping people awake at night, a good trick is to squeeze the wiring into a tight bundle using large zip ties every foot or so and leaving the tail of the zip tie in place to push the wiring to one side of the mast. The masthead fitting plate has a hole in it for sending the wiring bundle through. It is then closed off with a plastic plug and the cracks caulked.


At the mast heel there is an indexing bolt that is used to align the mast with a recess milled into the mast hinge. It also serves the function of keeping the mast captive within the mast hinge.

Next down is the mast tabernacle. The mast slides through the 1-foot pipe that is part the top tabernacle hinge and is held captive by it because neither the masthead fitting nor the mast heel fitting can slide past it. The inside of the top tabernacle hinge pipe is coated with graphite-loaded epoxy to create a low-friction surface. When raising the mast, it is slid aft until the mast heel is aligned with the bottom of the hinge plate and rotated until the head of the indexing bolt fits into the matching recess in the hinge plate. Another bolt is then screwed in to hold the mast to the hinge, preventing it from slipping as it is raised.

Part of the top tabernacle hinge is a fitting that accepts a 5-foot gin pole which is used to raise and lower the mast using a hand winch. It is a solid 2½-inch steel rod that has to accept well over 1000 lbs. of load without flexing.

The top tabernacle hinge is connected to the bottom hinge using a slightly tapered hinge pin. A second tapered hinge pin is inserted on the opposite side of the hinge to secure it in place as soon as it is raised. The hinge pins can then be pounded until the joint and tight and secured using a nut and a stop nut. This immobilizes the hinge, preventing friction and wear.

All of the wiring going through the mast has to be fitted with connectors at the mast tabernacle. The connectors should be waterproof, because there will inevitably be condensation inside the mast.



At the bottom of the tabernacle is the thrust plate, which rests on deck, where it is, again, coated with epoxy loaded with graphite powder, creating a low-friction bearing surface. The tabernacle fits snugly over the mast trunk, which rises 3 feet above the deck.



Where the mast trunk penetrates the deck it is pinned into place and caulked, to prevent deck leaks. Thus, the mast trunk hangs from the deck rather than resting on its heel. Instead, its heel floats in its heel fitting, which is fastened to the bottom of the boat via a wooden block cut to the appropriate angle. The mast trunk heel fitting is not subjected to any vertical loads, only horizontal ones, which the bottom of the boat can readily handle. The mast trunk incorporates a slot that accepts the mast wiring bundle, which snakes all the way down into the bilge, through the mast trunk heel fitting, and back toward the cockpit. Within the cabin the wiring is hidden by installing a decorative cover over the slot.

A key feature of the mast trunk is the notch. It is located an inch or so above the deck and is the designated failure point in a dismasting event. The depth of the notch is calibrated so that the mast trunk is only slightly weaker than the mast tabernacle or the mast. Once the mast trunk snaps off, the mast and the tabernacle are free to topple overboard as a unit. Some amount of additional damage is inevitable. The wiring bundle will be pulled apart and the masthead instruments are likely to be destroyed. To free the mast, several lines need to be released: 4 running stays, the sheet, the halyard and the reefing line. But this isn’t a lot of work: 4 on snap shackle pins released and three rope clutches opened. Dismasting made easy!

But what is most important is that the rest of the boat remains undamaged. After a dismasting event, a Quidnon owner can say “Masts? What masts?” shrug and motor on nonchalantly. When the time comes to replace the masts, any welding/machine shop can fabricate a new mast tabernacle and mast fittings, any wood shop can make a new mast trunk, any canvas shop can stitch together the sail out of Sunbrella fabric (a tough material used for awnings), the pipe for the masts is quite standard and easily obtained, and masthead instruments and rigging components can be mail-ordered from the usual outfits. The rest is just puttering about, to be done at one’s leisure. And if the masts and the sails can be salvaged, then all that needs replacing is a piece of wood (the mast trunk) and some masthead instruments.

The only difficult task in replacing the masts is heaving them onto the deck arches. Each mast weighs around 200 lbs, so it is best to have at least three strong-backed people on hand to assist with this operation. The easiest way to do this is to place the masts on the dock next to the boat and roll them aboard using two loops of rope or strapping, one placed fore, one aft. One end of each loop is secured, and the other one pulled, rolling the mast onto the deck arches and into place. With this technique and four people, two people are pulling, exerting 50 lbs. of force each, and two more are making sure that everything stays nice and even. Once all the pieces are in place, the masts can be raised.

Prior to being raised, seven lines have to be attached to the masthead:

• Four running stays, two forward, two aft

• Two topping lifts, one forward, one aft

• One halyard, aft

These can be draped over the deck arches to keep them from snagging on things or getting dropped in the water as the mast comes up. The running stays can be shackled to their respective pad eyes on deck ahead of time; the rest of the lines can be tied off at the nearest available deck cleat.



For the foremast, the gin pole interferes with the forward deck arch, and so the deck arch, which is hinged at the front, is tilted forward and out of the way for the duration. This involves loosening two turnbuckles and removing two clevis pins.



The masts tend to wobble between port and starboard as they come up, or lean to port or starboard, or both, especially if there is a bit of a sea running, or if the boat lists a bit from the way it is loaded, or if there are wakes from passing boats. This is nothing to worry about: the mast tabernacle can spin around on the mast trunk. Once the mast is all the way up it can be rotated to the correct fore-and-aft position out by putting some extra tension on the hand winch line.

The masts have 1º forward rake (meaning that they lean forward 1º) and once they come up all the way they flop decisively into place. At that point, the second, forward hinge pin is inserted and the hinge pins pounded in and secured in place using nuts and stop nuts. The hand winch line can then be removed. The next step is to install the running stays.

Quidnon’s method of keeping the pants up is the “belt and suspenders” method. The mast trunk is the belt, and keeps the mast up even by itself, but it is not sufficient to withstand the pull of the sails or the rocking of the masts in heavy weather. For this, running stays (suspenders) are needed as well.



For the running stays, galvanized steel wire rope is an economical choice, but it tends to be rather cumbersome to store between sails because it has to be coiled. A more expensive but excellent choice is Spectra or Dyneema, which are synthetic fibers that are just as strong but so flexible that they can be stuffed into a bag. There are four running stays per mast, all going to the sides of the deck, two forward (to oppose the weight of the sails) and two back (to oppose the pull of the sails). The running stays need to be clipped into place and tensioned before the sails can be put up.



The procedure for raising the masts is now pretty simple:

1. Attach lines to masthead fitting, drape them over the deck arches; clip running stays into place

2. Roll the mast into position

3. Rotate the mast until the indexing bolt fits into its matching recess

4. Thread a bolt through the tabernacle hinge and into the mast (wait to tighten it until the mast is up)

5. Connect mast wiring cables at tabernacle hinge; test the circuits for opens and shorts

6. Attach gin pole (insert into top tabernacle hinge, insert retainer clevis pin and ring-ding)

7. Attach line from hand winch to D-shackle at the end of the gin pole

8. Heave the mast upright using the hand winch

9. Insert second (forward) hinge pin

10. Pound in and secure hinge pins

11. Tighten the bolt in the tabernacle hinge that holds the mast in place

12. Tension the running stays

The procedure for taking the mast down is almost the exact reverse of the one for raising it:

1. Pull the lines in the running stay purchases out of their jam cleats and flake their lines on deck so that they run out as the mast comes down

2. Loosen the hinge pins (loosen the lock nuts and the nuts and given the pins a tap so that they turn freely)

3. Attach the line from the hand winch to the D-shackle at the end of the gin pole and take out most of the slack

4. Take out the second (forward) hinge pin

5. Get the mast started by pulling back on it using any of the lines that run from the masthead

6. Ease it down using the hand winch; horse it onto its rollers if it comes down at an angle.

7. Detach the line from the hand winch to the D-shackle at the end of the gin pole

8. Detach gin pole (take out ring-ding, slide out clevis pin, remove gin pole from tabernacle hinge)

9. Disconnect masthead wiring at the tabernacle hinge

10. Remove the bolt that holds the mast in position

11. Slide the mast forward

12. Detach lines from masthead

I wish it were possible to simplify this procedure from this 12-step program, but I don’t see how. As it is, the design achieves the following important objectives:

• The masts are secure and unobtrusive when stored on the deck arches and don’t add to the overall length of the boat (thus avoiding any added expense)

• The masts can be raised and lowered by just one person in a couple of hours (probably less with practice)

• In the unlikely event of a dismasting, there is unlikely to be severe damage to the hull and the injured mast can be dropped overboard by undoing four snap shackles and releasing three rope clutches.

• A salvaged mast (which may survive undamaged) can be reinstalled after replacing a single sacrificial wooden component, spares of which can be kept on board, plus the ruined masthead instruments

The entire sailing rig design is at this point far enough along to be set aside for now; the next step is to produce detailed fabrication drawings. Some other previously missing parts of the design, such as the engine bracket (which slides up and down) are pretty much done too, and are at the same stage, but are not exciting enough to deserve an entire blog post.

Therefore, we will now move on to mapping out the build process, starting with the deck, then moving on to the frame and the bulkheads, the bottom, the topsides and, finally, the surface of the deck and the superstructure (which can be completed with the boat in the water).

Wednesday, May 22, 2019

The Rudder

Rudder assembly
Quidnon’s steering has evolved quite a lot since the original concept. Now all that’s left of the original concept is the idea that the rudder should have a kick-up blade: when sailing across shallows it should gently float up instead of getting torn off or getting stuck, and when the boat settles on its bottom at low tide the rudder blade should automatically get itself out of the way. Only now has a good solution to this problem finally been found.

Early on it was thought that twin rudders and wheel steering made sense, but this made the design complicated and expensive. Twin rudders require a complicated steering linkage that uses something called Ackermann geometry, which is also used in cars: when turning to the right, the right wheel has to turn more than the left wheel because, being closer to the point around which the car turns, it has to follow a tighter circle.

Later on, after single-handing a 36-foot sailboat from Boston to South Carolina, I discovered that wheel steering is a bad idea and that I prefer a simple tiller. There are very few steering positions that are comfortable with a wheel: sitting behind it and standing behind it are more or less the only choices, and they both get tiresome rather quickly. On the other hand, with a tiller, it is possible to steer the boat while standing, sitting or lying down, using hands, feet and hips, or, with a tiller extension clipped on, with the inside of the knee or the armpit. It is possible to operate the tiller remotely, by tying a bungee cord to one side of it and pulling it to the other side using a lanyard.

In turn, a tiller on a boat of Quidnon's size is only workable if the rudder is a balanced rudder, with about a third of its area ahead of its rotational axis, so that the boat can be steered with a fingertip instead of your heel on the tiller pushing with all your might, as is the case with an unbalanced “barn door” rudder that rotates around its forward edge.

Further on, I discovered that Quidnon doesn’t heel enough to make twin rudders necessary: just a single rudder would work fine, and so the design was changed to a single rudder hung off the center of the transom. But this arrangement was still somewhat problematic. First, the rudder assembly cluttered up the transom and made the boat a bit longer (which is a problem because marinas charge slip fees by overall length). Second, the pivot point of the rudder was too far from the cockpit to give the tiller a useful swing range.

Rudder assembly installed in engine well
And so the rudder was moved from the transom to the back of the engine well, where there is just enough room for it. This made it possible to solve a few more problems.

Quidnon doesn’t always need to have a rudder. It is a houseboat, and houseboats mostly just sit at the dock, where having a rudder is not just unnecessary but also rather inconvenient. The tiller tends to whip around and hit things whenever the tidal current shifts or a boat wake hits. Since it sits in the water, it tends to accumulate marine growth which makes it not work very well when the time comes to move the boat. A better solution is a rudder assembly that is easy to install and just as easy to take out again when the boat is at rest.

Gudgeons in engine well: top view; aft view

With the rudder assembly removed, all that remains on the hull are two gudgeons bolted to the back of the engine well along the centerline. To install the rudder assembly, it is turned 90º, so that the tiller faces directly sideways and lowered into the engine well using a hoist. The rudder shaft has two pintles that engage with the gudgeons. The lower pintle has a longer pin than the upper pintle, so that it can be engaged first rather than having to try to line up two pintles with two gudgeons at the same time.

Once the rudder assembly is dropped into place it can be turned to the 0º amidships position, with the bottom part of the assembly sliding under a recess in the bottom of the transom. This recess serves several purposes: it provides an exit path for the stream from the propeller; it also provides an exit path for the outboard motor’s exhaust when it is in idle (when it is in gear the exhaust goes through the propeller and into the water); lastly, it provides a space for the rudder assembly.

The bottom part of the rudder assembly consists of the rudder blade case and the rudder blade. The case is a box, welded out of mild steel and galvanized, with its bottom and rear open and forming a slot from which the rudder blade protrudes. It is welded to the bottom of the rudder shaft (a steel tube) and reinforced using a triangular gusset. The gusset has a hole in it for attaching a lanyard by which the rudder assembly is hoisted out of the engine well. The sides of the box have specifically shaped cut-outs in them.

The rudder blade is made of a 3/4-inch (20 mm) piece of plywood sheathed in fiberglass and painted. Close to the bottom of the blade is a circular cut-out that is filled with a lead disk, to ballast the blade to counteract the buoyancy of the plywood and to exert a certain downward force when submerged. The top of the rudder blade is surfaced with epoxy that’s loaded with graphite powder, to create a hard bearing surface.

Rudder blade detent mechanism: roller guide and rollers

The rudder blade is joined to the rudder blade case using 4 rollers, 2 on each side, that are through-bolted to the blade and ride inside the cut-outs in the case. The arrangement of the rollers and the cut-outs acts as a detent: in order to get the blade to kick up the force acting on the front of the blade generated by an obstacle has to be more than 4 times the downward force on the blade due to gravity.

The lead disk is sized so that this force is significantly more than 1/4 of the force generated by drag with the boat moving through the water at its maximum speed. Once this initial resistance is overcome, the rudder blade kicks up rather easily. Once the external force acting on it is removed (because the boat is again in sufficiently deep water) it floats down into vertical position and the roller mechanism clunks into place. When the blade kicks up, it fits in the recess under the transom.

Rudder blade in kicked-up position

The only necessary precaution is to avoid running aground while moving astern: the rudder blade will not kick up backwards. Most of the time the centerboard will strike bottom first, because it hangs down lower, and will stop the boat, shattering if it has to, in which case it will be time to pull the remainder of the centerboard out of its slot on deck and to drop in a new centerboard. But if the centerboard somehow misses the underwater obstacle and the rudder blade doesn’t, then the rudder may suffer a bit of damage.

If the bottom is soft and the boat is moving slowly, it will simply stop with the rudder blade stuck in the sand or the mud. If the obstacle is hard or the boat is moving fast, the bolts holding the rollers to the rudder blade, which are designed to be the weakest element, will shear off and the rudder blade will drop off. Then it will be time to pull out the remainder of the rudder assembly and to jump down into the water (all 4 feet of it) to recover the rudder blade and the rollers. Then the rudder assembly can be put back together with new bolts. There is also the chance that the rudder blade will strike and damage the prop, in which case it will also be time to pull up the motor and replace the prop. In short, don’t run aground when backing up!

To summarize: the rudder assembly easily installed and easily removed when not in use and for maintenance. With the rudder assembly removed, all that remains in place are two gudgeons mounted to the back of the engine well. It doesn’t kick up unless it encounters a hard obstacle, with no amount of moving water able to displace it from vertical. Its action is fully automatic, never requiring any operator intervention. It provides for fingertip steering using a tiller because the rudder blade is balanced, with 1/3 of the area ahead of its axis. The use of the tiller makes it possible to use the simplest and most affordable kind of autopilot: a tiller pilot that clips onto the tiller. The tiller itself is of a telescoping type, with a handle that slides into its body, so that it isn’t left swinging about the cockpit when the boat is on autopilot.

After all of the various evolutions, I dare say that this rudder design is very close to final.

Monday, May 13, 2019

The Centerboard


Although the Quidnon blog has been quiescent for the past three months, there has been some good progress on completing the design, and I can now report these results and see what comments, ideas and suggestions emerge. It takes time to come up with simple and cheap solutions to complex and potentially expensive problems.

One of the problems that is now solved is how to provide lateral resistance with minimal complexity and expense. The initial concept included chine runners, which are narrow ledges that extended horizontally from the hard chines at which the bottom joins the sides, and two centerboards that hung down from wrist pins and extended from slots in the bottom in such a way that they would kick up into their slots when encountering an underwater obstacle.

The chine runners were discarded when it turned out that Quidnon’s hull, being quite wide in order to provide relatively spacious living quarters (it is, after all, a HOUSEboat), doesn’t heel enough to allow the chine runners to bite into the water. All the chine runners did was add some drag (and, of course, complexity and expense).

The kick-up centerboards worked well enough, but there is a basic problem with them: since they hang down from a hinge, they are deflected when moving through water, and this makes for erratic steering behavior. The deflection can be minimized by adding ballast, but this makes the boards too heavy. It is also possible to add tensioner lines fed to cleats that pop open when the boards hits an obstacle, but this adds complexity.

The problems with the original centerboard design didn’t end there. How does one remove them for maintenance and cleaning, and put them back in? If this required the boat to be hauled out, then that would invalidate the very important requirement that Quidnon must never need hauling out (haulouts are expensive!). The copper cladding can be cleaned with the boat hard aground at low tide and there is nothing else down there that should ever need attention. And so a plan was created for installing and removing the centerboards with the boat in the water with the help of a diver. But divers are also expensive!

And then another good question arose: why are there two boards? Well, the initial thinking went as follows. Putting a single centerboard along the centerline wastes precious living space in the middle of the cabin by filling it with a centerboard trunk. Moving it off to the side makes the design asymmetric, and that’s functionally unimportant but aesthetically unpleasing. Therefore, let’s have two of them. The flaw in this logic is that the aesthetic consideration matters not at all because the centerboard isn’t visible. Your heart is on your left and your liver on your right, but nobody will ever call you ugly because of that.

If two centerboards are too many, how about zero centerboards? Well, it turns out that having a centerboard is rather important, but only when the boat moves. It is especially important when motoring in and out of marinas, because without the centerboard the boat will drift sideways instead of turning within a tight radius. It is also important when motoring, especially upwind. It is sometimes possible to sail downwind without the centerboard, but that’s about it. But if the boat doesn't move (as houseboats often don't) then a centerboard isn't needed at all, and having one that's quick and easy to install and remove would be a bonus.

And so just one centerboard is both necessary and sufficient. It will be located off-center (to starboard) with the centerboard trunk located unobtrusively in the back of a settee in the salon, sandwiched between it and the water tank. (But we’ll still be calling it a centerboard because offcenterboard is not a word.) The centerboard trunk forms an L-shaped slot that extends from the deck all the way to the bottom (and does extra duty as a deck drain). To one side of the slot is a channel that stops short of the bottom and tapers in a specific way before it stops.


The centerboard is just a piece of 3/4-inch plywood covered with fiberglass for durability. A circle is drilled out of it near the bottom and filled with lead in order to make the centerboard heavier than water, but not much heavier. It doesn’t have to sink particularly aggressively; it just can’t float up. To one side of the centerboard, near the top, is screwed a cam that rides inside the channel on the side of the centerboard trunk. At the very top of the centerboard is a hole used to attach a lanyard by which the centerboard is retrieved. If the lanyard breaks, a boathook can be used to grab the board by the hole. The centerboard is sacrificial and designed to snap without causing damage to the hull. Making a new one is neither expensive nor difficult.


The centerboard will spend most of its life sitting flat on deck. When the boat is getting ready to move, it is installed by unceremoniously dumping it into its slot.


If there isn’t enough water under the boat it won’t go all the way down, but that’s usually not a problem. (You may need to give its lanyard a tug when backing out of a shallow berth, to keep it from catching on things.)


When the centerboard hits something underwater with the boat moving forward (as boats normally move) it deflects aft, but in order to do so it needs to ride up a bit, so that the cam moves up inside the tapered slot. It can stay in this semi-retracted state, bouncing along the bottom, while the boat sails or motors across shallows. This will slow the boat down a bit, but will also provide good steering because the boat will pivot around the board as it digs a shallow trench in the sand or the mud of the bottom.


It is not necessary to remove the centerboard when anchoring above the low water line with the intention of drying out at low tide because it will be forced up entirely into its trunk.

This completes the conceptual design of the centerboard; next on the list are: the rudder; engine mount; mast steps and bow structure. These have all been reworked, and I will be detailing the new designs over the coming weeks.

Friday, February 8, 2019

Frame Joinery Redux

Although most of the problems with hull structure have already been solved, there remained one problem that stood in the way of completing the design: how to join together the frame. It consists of 4x4 softwood (fir) timbers (3.5x3.5 finished size) combined into a box structure that reinforces the bottom the deck, the bow and the transom and provides support for mast steps. After working out a design that included a dozen different steel brackets that had to be custom-fabricated at considerable expense, I realized that I don’t like it at all: too complicated and too expensive. And so, as usual, I sat back and waited for some new ideas to filter in from the ether.

Eventually this happened. An unrelated project required me to build a rectangular frame by joining together some square cross-section sticks using L-brackets. To avoid the wood at the ends of the sticks splitting as I drove in the screws, I wrapped the ends using several turns of fiberglass packing tape. It worked just fine. The tape took up all the force that would have gone into splitting the sticks along the grain, and the resulting joins were impressively strong.

Transferred to Quidnon’s frame design, this technique will make it possible to assemble the frame using just 3-inch-wide perforated steel strips cut to two or three different lengths and bent to various angles. Some of the brackets will need to be bent to specific angles other than 90º, but this is not a complicated procedure.

The procedure for fabricating the frame now consists of the following steps:

1. Using a chop saw cut 8-foot 4x4 timbers to required lengths.
2. For each timber, shave down the first 6 inches off each end on all four sides using a planer.
3. For each timber, router off the corners on the first 6 inches on all four sides using a router.
4. Roll on a layer of epoxy to the prepared ends, wait until it “tacks up.”
5. Wrap each end in three layers of 6-inch-wide fibergass tape.
6. Saturate the tape with epoxy; let it cure.


Frame assembly then consists of matching up the timbers and the brackets and connecting them together by driving in a lot of self-tapping screws using a cordless drill. There is no need to worry about the wood splitting, and the resulting joints are strengthened by the fact that they are pre-stressed: the wood is compressed between the screws and the fiberglass. In a humid marine environment the timbers will gradually absorb moisture and swell, increasing the pressure on the fiberglass and the screws, holding them in place securely. (The choice of softwood for the timbers is critical: when hardwood swells, it generates enough force to burst fiberglass.) The strength of the joint is determined by the force needed to crush the wood fibers, which is somewhere around 6 times greater than the force it takes to split them along the grain.


There are still several more complicated pieces that will need to be fabricated: engine bracket, mast tabernacles, masthead fittings, tiller and keelboard hardware and bow rollers. These are all key elements of the design and there is no way to simplify them. But the frame joinery is now very well in hand and can be done cheaply using components that can be locally sourced in many places around the world.

Friday, October 12, 2018

A HOUSEboat vs. a houseBOAT

The most important design aspect of a tiny house is the success of its interior layout. The tight quarters may look quaint on paper but in reality turn out to be claustrophobic. The need to stoop and to contort yourself to fit into the small spaces may lead to bumps on the head and cramps. Lack of storage may seem inspirational for those aspiring to minimize their earthly possessions, but inevitably results in clutter. Lack of private spaces may inspire greater intimacy short-term but lead to strained relations in the longer term. And so on.

The set of such problem to solve is even greater when designing a houseboat because of the need to compensate for the almost constant rocking motion in all but the most sheltered marinas and anchorages. Berths (beds) have to be oriented with the head pointing aft: cribs rock side to side and while having your feet bounce up and down is tolerable, having your head do the same generally isn’t. There can’t be any sharp corners, especially where your head or your knees and elbows might end up, and there have to be handholds within easy reach. Shelves and tables have to be fitted with fids to prevent items from rolling off. Dealing with the inevitable condensation is far more important on a boat due to its proximity to water. (Many sailboats will drip cold water on your head as you try to sleep.)

These problems are easily solved by paying a few million dollars for a megayacht, but our goal is to make living aboard an affordable, comfortable, competitive alternative to paying rent. Not only does this tiny house have to float, but it has to be mobile and move both under engine and under sail. The constraints that this imposes on its design are quite formidable. Consequently, only now, after several years of design effort, is it approaching the point where there are no conceptual problems that remain to be solved and construction planning can begin.

Until recently, the design was close but not quite all there. Headroom was adequate for a boat but not for a house—not enough for a tall person to stretch. The cabins were reasonably sized but odd-shaped because of the curvature of the hull. Ventilation was adequate in some spots but missing in others… and so on. The breakthrough came from a very simple realization:

If Quidnon doesn’t make a good tiny house, it won’t matter how good a boat it is.

Previously, we made an effort to appease boat enthusiasts who look for “sweet lines” (curves, that is) and sailing performance (sailing against the wind, that is). Curves are expensive because they add complexity in engineering and construction and result in lots of scrap, while sailing performance to windward is a ridiculous thing to strive for in a houseboat, especially one that has a motor that can be turned on whenever the wind becomes uncooperative.

The effort to indulge and appease the sensibilities of sailing enthusiasts was not successful. They thought that Quidnon was ugly, ungainly and uncompetitive—as a boat. What they thought of it as a house—specifically, as a tiny house—well, they probably didn’t. Sailing enthusiasts either have lots of money to burn or live vicariously through those who do and aren’t interested in tiny houses. And so their opinions didn’t help advance the project.

There is a basic rule that applies aboard boats: if a thing isn’t useful, then it belongs overboard. And so it will be with all of the non-practical considerations that have burdened this project since its inception. Quidnon is a HOUSEboat, not a houseBOAT. Since most of these considerations were purely aesthetic, jettisoning them will not negatively impact performance.

If Quidnon is first and foremost a house, then, like virtually all other houses, it should be rectilinear, with right angles everywhere; basically, a box. There are good reasons why houses are rectilinear: curved floors and slanted walls are nightmarish to live with and more expensive to build. In a rectilinear design all the dimensions can be read off just two drawings—plan and elevation; most of the cuts needed to make parts are at right angles, resulting in less scrap; most of the assembly can be done using a tape measure and a carpenter’s square.

Are there any boats that are rectilinear? Yes, there are, and they are quite ubiquitous. They are called barges. And so Quidnon is now a barge, with just a couple of small concessions to sailing efficiency: the bow is rounded rather than slanted and the aft section of the bottom is curved so that the transom just kisses the waterline. These tweaks improve performance somewhat: the bow generates less resistance while the transom doesn’t drag water behind it. These tweaks don’t add much to the cost or the complexity of the design and don’t produce too much scrap.

Speaking of scrap, minimizing it is key to minimizing the construction cost of the hull: it’s material that you pay for but then simply throw away. Not only that, but you have to actually make the scrap: every piece of wasted material has to be cut out of a piece of stock to make the piece that you are actually going to use. Quidnon minimizes scrap by using whole sheets of standard 4x8-foot (1220x2440mm) plywood as often as possible.

For example, the deck layout is 16x36 feet. Ignoring the openings for the hatches, cockpit and engine well, which do generate some amount of scrap, it is constructed out of two layers of ¾-inch (20mm) plywood screwed and epoxied together (which is then covered with a layer of fiberglass and epoxy and surfaced with aluminum diamond hatch).

Note the tiling pattern: in order for none of the seams to overlap between the two layers, out of the 36 pieces of plywood only five need to be cut in two. This is most easily done on a panel saw. The layer with the cuts will be ¼ of an inch narrower than the layer made up of whole sheets because of the 1/8 kerf of the cuts. But ¼ of an inch distributed across 7 gaps is less than 1mm per gap and is negligible.

Similarly for the sides and the bottom. Each side is made of 18 sheets of 4x8, only one of which has to be cut in half lengthwise. Some amount of scrap then needs to be cut away to make the profile of the bottom and the bow. But then the construction of the bottom hardly generates any scrap at all. The overall goal is to have less than 10% of the plywood end up as scrap.

In addition to minimizing scrap, the barge hull shape has made it possible to dramatically improve the ergonomics of the cabin layout. Headroom is 6½ feet (2m) just about everywhere. There are four double-berths (beds) that are 6 ½ by 4 feet (2m by 120 cm). Most importantly, there is now room for a very comfortably sized stateroom (living room) in the bow.

Let’s take a tour of Quidnon’s redesigned cabin, starting at the bow and working our way toward the transom.

When I first started designing Quidnon, the very first seemingly insoluble problem I came across was where to put the couch, the coffee table and the TV. Few reasonable people would agree to live in a house that’s missing a living room, a den or similar. Having looked at a lot of boat designs, both sail and power, none of the reasonably small, reasonably priced ones had anything that resembled the traditional living room found in most homes. A good living room has a couch, one or two armchairs, a place for a TV set, a few end tables and a coffee table to tie it all together. The best ones have lots of natural light and a great view.

So, how can Quidnon provide all of that? Switching to a barge hull opened up what was before an awkward, cramped wedge-shaped space in the bow (that is found on most boats) into a spacious 160 sq. ft. (15 m2) rectangle. There is room for a wrap-around couch, two end tables, a huge 3 by 6 foot coffee table and enough bulkhead space to mount two 50-inch screens.

There is also quite a bit of storage space: 10 cu. ft. inside each of the end tables and 20 more under each of the port and starboard settees (couches; the seats tilt up) for a total of 60 cu. ft. (1.7 m3).

Above the settees there are two rows of shelves with 34 linear feet of shelf space, enough to hold a 500-volume library.

Above the shelves is a row of deadlights (which are portlights that do not open). The commercially available deadlights and portlights start at around $200 each. For Quidnon’s 44 deadlights, that would come to at least $8800. To avoid this expense, Quidnon’s deadlights are just 1 ft. diameter holes milled through the hull with a layer of 1/4-inch polycarbonate plastic caulked and fastened over them on the outside. Since the holes weaken the structure of the sides by around 50%, this is compensated for by doubling the hull thickness by adding two strips of plywood, 16 inches wide, over the holes. The materials cost for the additional plywood and the polycarbonate is around $1200.

Lastly, the two red boxes in the two corners of the bow are air vents that are connected to a deck arch above. The vents are louvered and can be adjusted for both intake and exhaust of outside air.

Moving aft from the stateroom is the salon, which can be partitioned from the stateroom by a folding divider.

The salon contains two facing settees (couches) with a drop-leaf table between them. On both sides of each settee is an end table. The seats of the settees tilt up to provide access to the storage space beneath them, providing, together with the end tables, 40 cu. ft. of storage space.

In the center of the table, between the two drop leafs, is a vertical slot that is ideal for securely holding laptops and tablets, cell phones, keys, wallets and other small but important items.

Above the table is a large translucent hatch (skylight, shown in light green) that provides a lot of light. It is designed to prevent ingress of all forms of water (rainwater, sea spray, condensation) and can be angled up slightly for ventilation. It can be removed completely for loading and unloading, making it unnecessary to haul heavy loads up and down the companionway ladder. A deck arch, mounted directly above it, provides an attachment point for a hoist.

On both sides of the salon are pilot berths. They are accessed through hatches that are above the backs of the settees and are separated from the salon by double longitudinal bulkheads that form the walls of the keelboard trunks. The pilot berths’ hatch doors are thick and filled with foam, and together with the double bulkheads provide excellent sound insulation and privacy.

The pilot berths (beds) are 6.5 by 4 feet—large enough to comfortably sleep two adults.

At the foot of each berth is a sea chest that provides 20 cu. ft. of storage space for clothing, children’s toys (the pilot berths are perfect for children and as nurseries) and other possessions.

The pilot berths are supplied with fresh air through air vents connected to a deck arch above. With the pilot berth hatches open, they can also provide fresh air to the salon.

Below the pilot berths are the water tanks. At 135 cu. ft. each, the two tanks provide 8 tonnes of salt water ballast. Fresh water is stored within these tanks inside floating bladders—up to 2000 gallons of it. As fresh water is used up, it is replaced by water from the outside using a pressure-activated pump. The use of water ballast adds a lot of versatility. It is necessary when moving under sail and/or through large seas; it is helpful when docked or at anchor, to reduce motion; it isn’t necessary or helpful when motoring on inland waterways and being able to dump it when hauling out or when recovering from a hard grounding is a positive benefit. It also saves lots of money (the equivalent weight in lead would cost over $16,000) and provides the added benefit of being able to store 2000 gallons of fresh water.

Moving further aft, there is the galley (kitchen) to starboard (right), the heads (bathroom) to port and a companionway (vestibule) in the center. Only the galley is shown in the elevation drawing. The galley cabinets provide 50 cu. ft. of pantry space.

The heads offers the usual amenities, including a full-size shower stall that can be fitted with a bathtub. All sorts of options are possible for both the galley and the heads, including composting toilets, flex-fuel stoves and the likes. If the stove in the heads is eliminated (not everyone plans to overwinter aboard in the Arctic or needs an on-board sauna) then there is enough room for a vertically stacked washer-dryer unit.

The companionway is an open area that links together the heads, the galley, two aft cabins, the salon and the cockpit via the companionway ladder. At the bottom of the companionway ladder is a foot locker while hooks along the sides of the companionway are for hanging outdoor clothing.

Aft of the companionway are the two aft cabins. Each has a table with a seat, a row of shelves and a double berth. The table can be used as a chart table and the shelves packed with navigation equipment, but it can also be used for doing any other type of sit-down work. Space under the berth provides 40 cu. ft. of storage space.

The aft cabins and the heads can be closed off using sliding doors (shown in magenta). These doors are counterweighted so that they don’t spontaneously slide back and forth due to the motion of the boat but stay in place.

Between the two aft cabins is the utility chase that includes the cockpit, the anchor chain and line locker beneath it, the engine well and the gasoline tank and propane locker further aft. The engine well is heavily insulated to dampen the engine noise when motoring. Since the engine is a gasoline outboard rather than a diesel, it produces a high-pitched whine rather than a heavy throb, and is easier to suppress using a few layers of foam.

This, then, is the tiny house that will also function as a houseboat and a sailboat. Some things about it are still distinctly odd for a house; the shape of the windows for one, the fact that you enter it via the roof (deck) for another. But this can’t be helped; if you could enter it at ground level, then so could water, and house windows don’t work at all when submerged.

Now that Quidnon is barge-shaped with no funny angles the joinery has become dead simple. It involves plywood panels screwed and glued to softwood strips. And then the entire hull gets fiberglassed on the outside, making it relatively indestructible.

Quidnon’s conceptual design is now complete. What lies ahead is producing the detailed mechanical drawings, the bill of materials, a parts list and a set of assembly instructions. Much to the dismay of boat hobbyists and enthusiasts, the sailors among them especially, it is manifestly and resolutely a HOUSEboat, not a houseBOAT. It will get built, and people will live aboard it. Once in a while this shoebox of a boat will erect its masts, drop in a motor, hoist the sails, promenade around the harbor in stately splendor and eventually disappear over the horizon, to the slackjawed amazement of tourists and bystanders.

Friday, October 5, 2018

Coppered Bottom is a No-Brainer

The last post on the Quidnon blog attracted some attention from various places around the net. One in particular—the forum Sailing Anarchy—attracted over 400 visitors. I followed the link and tried participating in the discussion.

The sailing anarchists just couldn’t wrap their heads around the concept of a houseboat as a lifehack that lets one avoid getting wiped out by exorbitant real estate prices and rents. Well, I’ve said this many times before, but I’ll say it again, briefly: in the US, housing is a racket, on par with other rackets, such as health care, higher education, national defense and quite a few others. The very lightly regulated recreational vessel space offers a wonderful opportunity to escape the landlubber debt trap.

The sailing anarchists also couldn’t accept the idea that it is better to build a boat from scratch, at considerable expense, than to buy an existing, used boat, many of which can be had for very little money. The problem there is that none of the existing boat designs fit the bill. Sailboats are either big and unaffordable or small and too cramped. Powerboats with accommodations for a family are also too expensive, both to own and to move from place to place because of exorbitant fuel bills. Houseboats are generally dock-bound and not seaworthy in any sense.

Some anarchists thought that the Junk rig wouldn’t work well. Little do they know that the Junk rig is one of the oldest and most successful designs in the world that has stood the test of time, providing low-cost propulsion and ease of handling for more centuries than any other. Some thought that the boxy hull shape was unstylish, ugly and simply wrong, unaware of the fact that sailing barges, scows, cargo lighters, dhows, bateaux and junks of similar lines had been the staple of coastwise navigation around the world throughout the age of sail.

I presented my list of requirements which Quidnon must fulfill, but which no other boat does, to no avail. Apparently, these anarchists are rather closed-minded. Not a single comment they made was on target. But one valid question did come out of the discussion: Why cover the bottom with copper sheet when bottom paints are available. Since this is an easy question for me to answer, and since the answer is instructive and demonstrates the type of thinking that informs the whole design, I will answer it.

Quidnon’s bottom is 16 by 36 feet, or 576 sq. ft. The bow, transom and sides below the design waterline add an additional 208 sq. ft for a total of 784 sq. ft. Roofing copper comes in 4x8-foot sheets, or 32 sq. ft. Dividing one into the other gives us 25 sheets. 16-gauge (1/16-inch) copper sheet is currently priced at $91.29 per, for a total of $2,282.25.

This may seem like a considerable expense, but now let’s consider the cost of bottom paint. After much experimentation I settled on Interlux Micron CSC Ultra as the longest-lasting paint. It costs $209.99/gallon and its datasheet claims that a gallon of it covers 439.7 sq. ft in a single coat. The manufacturer recommends 3 coats and a minimum of 2. This gives us 784 sq. ft times 3 coats divided by 439.7 sq.ft/gallon, giving us 5.3 gallons or $1,123.

Note that the paint only works for about a year; after that, the bottom starts growing slime, then sea grass, then barnacles and mussels. If you don’t plan on going anywhere, then you can just let your boat turn into a floating island festooned with seafood. But the need to move may arise suddenly: the marina may close because of an approaching hurricane and kick everyone out; your job situation may require you to move your floating home to a new location; a shortage of money may require you to give up the slip at the marina and take up life at a mooring or at anchor. With a neglected, painted bottom the prerequisite to moving is an expensive and lengthy (3 days at least) haul-out which includes hiring a Travelift and someone to pressure-wash and paint your bottom (unless you yourself enjoy spending your days with a roller, wearing a bunny suit and a respirator, and being exposed to toxic fumes anyway). Haul-out and bottom painting costs vary, but you generally end up spending upwards of a thousand dollars, and if you want your boat to be able to move effectively, you need to do this every year.

And so by going with bottom paint instead of copper sheet you will save $2,282 minus $1,123 in construction costs, or $1,159. But every year thereafter you will spend a minimum of $1,123 + $1,000 or $2,123 in maintenance costs. Over the 30-year expected lifetime of the boat, this will amount to as much as $60,000. Compare that to copper sheet: yes, you will pay extra up front, but thereafter all you will need to do is a semiannual cleaning: find a sheltered, shallow spot that dries out at low tide, anchor, wait for the tide to go out, and then take a scraper on a long handle, a roofing spade or a similar hand tool and scrub all of the copper you can reach. The seafood you can’t reach will be crushed and fall off by itself. If that’s still too much work, then you can hire a diver to scrub the bottom for you while the boat sits at the dock. This service generally costs only a few hundred dollars and can often be done on short notice—when you find out it’s time to move.

Attaching the copper to the bottom is slightly technical but not particularly difficult. The bottom is made up of 3 layers of 1/2-inch plywood screwed and epoxied together. Fiberglass matt is then nailed to the plywood using bronze annular nails and saturated with epoxy. The matt is then covered with 3 layers of fiberglass cloth, leaving an epoxy-coated surface, tipped off with a soft brush to make it perfectly smooth. The task of attaching the copper sheet is then as follows:

1. Thoroughly abrade the epoxy on the bottom with 100 to 200-grit sandpaper using a rotary sander.
2. Clean off sanding residue using denatured alcohol. Be sure not to leave any fingerprints.
3. Thoroughly abrade one side of a copper sheet with 300 to 600-grit sandpaper using a rotary sander.
4. Degrease using trichlorethylene.
5. Rinse the copper sheet in one of two solutions for 1-2 minutes. Option 1: 6 parts copper chloride, 30 parts 70% nitric acid; 200 parts water. Option 2: 25% aqueous solution of ammonium persulfate.
6. Rinse with distilled water; let dry.
7. Coat the bottom evenly with epoxy and apply the copper sheet prepared side down. Use cotton gloves when handling the copper sheet to avoid contaminating the contact surface.
8. Cover the copper with polyethylene sheet, then weigh it down with sandbags until the epoxy has set.

Why don’t other boatbuilders use copper cladding for the bottom? Well, it used to be a popular option during the age of sail. Ships were periodically run aground (careened) to have their bottoms scrubbed. But ships now use powerful bottom paints (illegal for use on smaller recreational boats) while for smaller boats copper is simply not an option. Look at the bottom of just about any commercially produced boat. It is made up of compound curves, and it is an expensive proposition to make copper sheets take up compound curves. Add to that the fact that most commercially produced recreational boats are made of fiberglass and vinyl rather than epoxy, and these don’t provide a good substrate for attaching copper sheet. Quidnon’s bottom is curved (slightly) in one direction only—fore and aft—and can be tiled with sheets of copper: 4 sheets across and 5 sheets lengthwise, for a total of 20 sheets with almost no scrap.

There is nothing to stop anyone building a Quidnon from deciding to use traditional bottom paint instead of the even more traditional copper sheet, but the decision to use copper appears to be a no-brainer: lower costs, no need for haul-outs and time spent on the hard in a boatyard and generally more flexibility.

Monday, September 17, 2018

Quidnon 2.0

This boat design project started out by setting out some very ambitious requirements:

• A houseboat that makes a comfortable tiny house big enough for a family
• A competent, seaworthy sailboat, with masts that can be put up and taken down by a single-hander with the boat in the water
• A motor boat with an outboard motor for an engine that can be installed and removed easily, positioned in an engine well to prevent cavitation, collision damage and other problems with transom-mounted outboards
• Never needs a haulout: copper-surfaced bottom resists marine growth; settles upright and can be dried out and scrubbed at low tide
• Can be beached and relaunched by rolling over logs using anchor winch
• Can be assembled quickly from a kit on a beach or a riverbank by moderately skilled people
• Uses materials that are readily available almost everywhere: plywood, softwood lumber, bolts and screws, fiberglass and epoxy, galvanized mild steel, polypropylene three-strand rope
• Designed for all climates and seasons, from frigid to torrid
• Can be constructed and maintained at minimal expense

Over the past four years since I launched this project several people have made significant contributions to it: modeling, prototyping, contributing ideas and criticisms, helping spread word of it. Taking our sweet time with it has been very helpful in preventing us from building the wrong boat.

But what would be the right boat? How will we know when we have the right design? Well, one very basic indicator would be an empty list of unsolved problems—problems not in the sense of having every last detail worked out on paper (that’s largely a matter of grinding out mechanical drawings) but in the sense of not being sure what to do. And until very recently the list of unsolved problems contained the following big ones:

• No good, useful interior layout for the U-berth (the front section, normally called the V-berth, but Quidnon’s bow is semicircular, making a U). We went round and round on it, but the space was just too awkward.

• No reasonable procedure for installing and removing the keelboards or the rudder with the boat in the water.

• Complex joinery that required pieces of lumber to be milled to a variety of bevels, then steam-bent, adding expense and making the kit difficult to pack flat.

• The angled twin rudders, and the rudder linkage that went with them, gradually grew in complexity to include Ackermann geometry, a system of levers for amplifying the tiller angle and various other details, making it quite baroque.

• There was no straightforward way to construct the chain runners so that they would be neither too fragile nor too heavy and expensive.

• Rolling the hull over logs is made difficult because the bottom is curved throughout, causing the logs to squirm out from under it.

There were a couple of other, relatively minor problems as well. I will mention them later on.

And then something happened that broke this entire logjam: I consulted with a marine architect who raised certain criticisms of the design. They made perfect sense, and forced a rethink that made all of these problems go away.

• The hull doesn’t heel enough to make chine runners effective. They only work well at a considerable angle of heel, and with a hull as wide as Quidnon’s the heeling angle is insufficient to make them scoop up enough water to stop the sideways slide. Solution: get rid of them altogether.

• The hull doesn’t heel enough to make it necessary, or at all useful, to angle out the keelboards or the rudder blades. Solution: make them all vertical. It then begins to make sense to make the keelboard trunks into full double longitudinal bulkheads with a slot between them, leaving them open both at the bottom and at the deck. Keelboards can then be loaded into the trunks from the deck. An added bonus is that this creates a double baffle between the salon and each of the pilot berths, providing sound insulation. Another added bonus is that there are now two large deck drains, to quickly get rid of any seas that climb aboard.

• There is no reason to introduce the cost and complexity of twin rudders. Solution: have just one rudder, mount the rudder post on gudgeons and pintles along the aft wall of the engine well with the rudder blade nestled in a recess under the transom (which is already included in the design, to let through the stream from the prop). Instead of the baroque linkage, we can then have a simple tiller connected to the top of it. When at anchor or at the dock, the rudder can be pulled out to reduce noise and wear.

• There is no reason to curve the sides or to angle them out. It doesn’t improve sailing or motoring performance at all, but it complicates the joinery. It is better to simplify the construction, minimize the cost and maximize useful interior space by making them flat and vertical. This gets rid of most of the complex joinery and the need to steam-bend pieces.

• If the sides are flat, there is no reason to curve the bottom throughout. It has to have a curve at the bow, to help it move smoothly over the water, and it has to curve up gently toward the transom, to avoid dragging water behind it and to keep its center of buoyancy where the ballast is. Giving it a generous flat section in the middle makes it possible to roll it over logs while further simplifying the joinery.

• The fancy bow, where the sides sweep together to meet the bottom at a flat point, will not help performance. On the other hand, it is what makes the space in the bow so difficult to make any reasonable use of. The solution is to make a simple barge hull: at the bow, the bottom curves up to the deck with constant curvature while the sides are perfectly flat. This makes it possible to use the space as a comfortable livingroom of 114 sq. ft. (10 m^2).

What will the result look like? Well, my new motto is “Start your morning with a 3D model and get it over with.” Here is the 3D model, constructed out of highest-quality cardboard and scotch tape.



Yes, Quidnon looks like a barge. That’s because it is a barge. Efforts to make it look like something else—by slanting and curving the sides and giving it a fancy bow added complexity and expense while taking away useful internal space. Also, these little nods in the general direction of yacht design did nothing to appease people who like fancy yachts with curvy lines—there is no pleasing some people!

These major simplifications make it possible to produce the detailed plans over the course of the next few months. This is important, because the money with which to build the first Quidnon should be in hand over the course of the next year, allowing us to move on to the next phase: building and testing it.