Tuesday, July 19, 2016

On Women, Boats and Plumbing

Plumbing systems on boats run from the very simple (a blue jerrican of water brought in from shore) to simple (a fresh water tank, a foot pump and a spigot over a tiny sink that drains overboard) to ones that are equivalent to the ones found in houses on land. Houseboats, in particular, generally have running hot and cold water supplied to a faucet in the galley, the one in the heads, and the shower head in the shower stall. QUIDNON will follow this general pattern, providing all the amenities people are used to having in their home on land.

Although the details of boat plumbing systems vary, all but the simplest ones share two significant commonalities: all of them break from time to time, and when they do repairing them involves the use of significant amounts of foul language while groping around in a cramped locker full of hoses cutting up one’s forearms on the sharp ends of hose clamps. Boat plumbing systems are virtually never designed with ease of maintenance in mind; mostly they are an afterthought, not so much engineered as crammed together in any space that’s available. A very common problem is that working on them requires the use of tools—screwdrivers, channel locks, sockets with ratchets—but there is no room to wield these tools in the normal manner, and just about every operation requires one to become a contortionist. Another common problem is lack of space for both the arm (with which to work on things) and the head (with which to look at what you are doing), meaning that much of the work has to do be done “by Braille.”

Boat plumbing is also a topic that brings out gender differences in stark relief. There is no shortage of men living quite happily aboard boats with minimal plumbing systems. They drink from a water battle, and sanitary arrangements consist of a “relief bottle” (what is done with its contents is rarely discussed). They shower ashore, at the marina or the gym, they eat out a lot, and all they really care about is having a place to sit, a bed to sleep in and a cooler for the beer. They may entertain female visitors on board, but if the accommodations are sufficiently spartan virtually none of the women volunteer to move aboard and see it as a sort of survivalist camping trip—interesting, perhaps, but unappealing for the long term. Sometimes this is by design. There is an abiding superstition among sailors that having women (and priests) on board brings bad luck. But there are also plenty of men, and women, who would like to live aboard as families, children included—provided the accommodations include a good plumbing system that provides hot and cold running water in the galley and the heads.

Very importantly, the plumbing system has to actually work. Since the system is on a boat, one naturally expects it to break on a semi-regular basis (a boat being a hole in the water you throw money into and all that) and when it does break, this tends to seriously disrupt domestic tranquility. This is because fixing the plumbing is, more often than not, considered “men’s work.” It is dangerous to generalize, and there are some exceptionally handy women, but there is also a preponderance of anecdotal evidence that the vast majority of women who live aboard boats limit their participation in dealing with plumbing issues to making announcements and asking questions.

The announcements can be quite emphatic, ranging from “There is no water!” or “There is salt water coming out of the tap!” to “I am going to the gym, because I want to take a normal shower!” and “I can’t stand this any more!” The questions can be quite challenging as well: “Why is the plumbing breaking down all the time?”, “Why can’t it be made to work reliably?” and “Why can’t we live like normal people?” As you may rightly surmise, plumbing emergencies occupy a spot at the top of the list of things that negatively affect domestic tranquility among liveaboard couples.

When an onboard plumbing emergency arises, the male part of the seasteading team takes out the tools, plunges his hands into a cramped locker filled with a tangle of hoses, promptly cuts himself on a hose clamp and starts using foul language. He would much rather work on something—anything—else, but he knows that if he can’t fix the plumbing problem quickly and definitively, his stock will plummet in value. Now, fixing the problem is generally quite possible—plumbing isn’t exactly brain surgery—but there are several adverse factors:

1. Most men aren’t plumbers and don’t quite know what they are doing.
2. Boat plumbing systems are weird and challenging even to natural born plumbers.
3. If you are on a boat, calling a plumber is an even more expensive option than it is on dry land.
4. If you need to replace something, you quickly find that “marine” replacement parts are at least twice as expensive as regular replacement parts simply because the word “marine” appears somewhere on the package.

But with QUIDNON things are going to be different, and in a good way, because the design of its plumbing system explicitly addresses these questions and concerns. All of the controls are laid out in a way that makes sense and makes them easily accessible. Schematic diagrams, diagnostic procedures and work-arounds for most common and even some uncommon problems make it easier to make repairs when something goes wrong.

The first two problems to address are the ones of cost and of the need for expert knowledge of plumbing. The solution is the same for both: use ¾-inch garden hose throughout: green hose for raw water, white hose for potable water, red (industrial) hose for hot water. Most men (in the US and Canada) can handle tasks associated with lawn care; lawn care involves the use of garden hoses; ergo, most men know how to screw together and fix garden hoses. You cut a specific length of hose that you look up on a chart, you slide on the ends of the appropriate gender onto each end, and you tighten them with channel locks. You make sure that the female end has a rubber gasket in it. Then you snake it into place and screw in the ends, by hand.

The garden hose-based solution is by far the cheapest, and the spare parts are very easy to come by: the gardening section of any hardware store is likely to stock all of them, while the plumbing section will provide the faucets and the shower head (no need for specialty “marine” parts). What’s more, people are always throwing away hose as soon as they get a single puncture in them, and so you can pick up all the spare hose you could ever need simply by making a habit of strolling past the marina dumpster. There are a few unusual items: a pressure reducer (the boat works at 15 PSI, not at “house pressure,” which can be anything), two demand pumps that run on 12V, an electric water heater and some additional odds and ends. These need not be “marine” either: any RV (recreational vehicle) supply place is likely to have all of them in stock.

Next is the problem of layout. On QUIDNON, the various valves are not located deep inside some locker but laid out sensibly between the three bottom steps of the companionway ladder, right above the slide-out shoe drawer. On every other boat I’ve looked at the companionway ladder is just a ladder, but QUIDNON is different: every item does several jobs. And so QUIDNON’s companionway ladder is at once a ladder, a shoebox, a plumbing control panel, an electrical control panel for both AC and DC circuits, a locker for boat documents, a locker for flares, handheld VHF radios and other emergency signaling equipment, and a firearms locker big enough to hold a shotgun, a rifle, a Glock and their assorted ammo. (If you don’t like guns, you can use it as a wine rack.) Here’s what the plumbing control panel looks like. Those little green valves are $2.49 each at Target, but I am hopeful that a quantity discount can be obtained.

Next is the problem of having plenty of freshwater on board, for those members of the crew who would never consider just shaving their heads and use shampoo and conditioner, and may even lather, rinse and repeat. The simplest solution is to live at the dock and to hook up a hose to the shore water system at the marina. In the north there is usually a summer water system and a separate winter water system with hoses run underwater and wrapped in electrical heating tape and insulation between the water and the boat. Further south there are no winter water systems and when there is a cold spell the water is simply shut off “until further notice.” Winter water systems sometimes freeze and get shut off “until further notice” anyway, and then everybody has to wash and shower at the marina bathroom, which gets crowded, causing tempers to fray. The solution, of course, is to have plentiful on-board water, which can be periodically replenished by pulling up to a fuel dock to fill the tanks. QUIDNON’s water tanks double as ballast—5 tons of it, or 1300 gallons—so there will be plenty of water on board. But it eventually runs out anyway, in which case you need to do the following:

• Dock some place where there is a water hose available (such as a fuel dock)
• Attach the water hose to the water intake
• Turn off raw water pump
• Open the raw water drain valves (to make room for fresh water)
• Program the DigiFlow 8000T water meter ($36.98 well spent) to count down from 1300 gallons
• Open the shore water intake valve
• Wait until the water meter starts beeping
• Close shore water intake valve
• Close raw water drain valves
• Program the DigiFlow 8000T to count down from 1000 gallons, so that it beeps when it’s time to start thinking about filling the tanks again
• Turn raw water pump back on

This is all simple so far, but now it gets a bit more complicated. Since the water tanks double as ballast, they have to always be kept full. This is accomplished by storing the fresh water inside a bladder that’s floating in salt water pumped in from overboard. When you turn on a tap, the raw water pump starts squirting salt water into the tank, squeezing fresh water out of the bladder and out of the tap. But what happens if QUIDNON is drying out on a sand bank or a beach at low tide (a fun thing to do with a ruggedly built flat-bottom boat) and salt water isn’t available? Now it gets complicated! You need to do several things, ideally before the raw water pump starts sucking air, and they may sound technical and complicated, but they really aren’t.

• Turn off raw water pump
• Close bypass valve
• Open both vent valves
• Turn on fresh water pump

Turning off raw water pump is an obvious thing to do; water pumps don’t pump air, and when you are drying out there is no raw water available. The bypass valve allows fresh water to flow around the fresh water pump when the pressure is supplied by the raw water pump, but since we will be using the fresh water pump, we need to close it. The vent valves need to be open to let air into the tanks as water is pumped out of them to avoid vapor lock. Turning on the fresh water pump is also an obvious thing to do.

Now, suppose you like living on the beach so much that you decide to stay, haul QUIDNON some distance away from the surf into the shadow of some coconut palms, and use it as a beach house. To do this, you walk the anchor to the shore, bury it, and then use the anchor winch to roll QUIDNON onto the shore over some logs. But while you are doing this you don’t want to be hauling five tons of water; you want the boat to be as light as possible. (You’ll deal with stocking up on freshwater later.) How do you do that? Here’s the step-by-step procedure, which starts where the previous procedure left off:

• Shut off fresh water pump
• Open all 4 drain valves
• Wait for water to dribble out

Bored of living on the beach and want to be sailing again? Once QUIDNON is afloat again, it’s time to fill the tanks with salt water:

• Make sure all drain valves are closed and both vent valves are open
• Open bypass valve
• Turn on salt water pump
• After pump stops running, close both vent valves

Bladders don’t last forever and although many years may pass uneventfully, eventually you will hear the words “There is salt water coming out of the tap!” What do you do? First, you isolate the problem. Run the tap, close the port fresh water tank valve and have a taste. Problem fixed? Then it’s the port tank bladder that’s leaking. There is nothing more that you have to do immediately. Is water still salty? Then it’s the starboard tank bladder that’s leaking. Open the port freshwater tank valve, close the starboard freshwater tank valve, and confirm that the water is no longer salty. Inform your partner that the problem is fixed (for now).

Now, to really deal with the problem you have to replace the leaky bladder. First, you have to drain the tank. For the bad tank:

• Open vent valve
• Close raw water tank valve (fresh water tank valve is already closed)
• Open both fresh and salt water drain valves
• Wait

Once the tank is drained, find the access plate. It’s a round piece of plywood bolted onto the back wall of the tank, held in place by six ¼-inch bolts arranged in a circle with a rubber gasket sandwiched in between. The port access plate is in the shower stall in the heads; the starboard one is under a cabinet in the galley. Empty the cabinet and put something underneath the plate to catch any water. There is a hose attached to a threaded nipple that sticks out of the access plate. Unscrew the hose, undo the 6 bolts, remove the plate and pull out the bladder that’s attached to it. Undo the hose clamp securing the bladder to the nipple inside the plate and remove the bladder. Coat the nipple with caulk and slide on the new bladder. Install and tighten the hose clamp, but not all the way. Wait for the caulk to harden, then tighten the clamp the rest of the way. Gently stuff the bladder inside the tank, reinstall the access plate (a bit of vaseline on the gasket should help keep it watertight) and reattach the hose. Open raw water tank valve. Once the tank is full, close vent valve and open fresh water tank valve. This is probably the most complicated and delicate plumbing repair that QUIDNON could call for.

But what happens if the pumps stop working? You are off sailing, or living at anchor, and suddenly one of the batteries develops an internal short circuit, discharging the rest of the batteries. (You probably shouldn’t have kept the battery bank selector set to “both,” but it’s too late now.) “There is no water!”—nor is there anything else that requires electricity! You need to isolate the faulty battery, disconnect it from the bank, then start the motor using the emergency pull chord and run it until the remaining good batteries are charged. But that’s thirsty work, and how will you keep yourself from becoming dehydrated in the meantime? Easy: open the tank vents and use the foot pump in the galley. Filtered fresh water will come gushing out of the spigot. You still need to fix the electrical system before you drink up all of your ballast, but it’s not too huge of a hurry—unless somebody really needs to take a shower right there and then. Be sure to close the tank vents once the raw water pump starts running again and the tanks are full once again.

Finally, there is the worst-case scenario: you are sailing along and hit something hard and pointy—a floating shipping container or a coral head—and put a hole in QUIDNON’s bow. This is hard to do, because the bow is clad in tough copper sheets, a thick layer of fiberglass and an inch of plywood, but there is simply no arguing with sharp rocks. Water starts gushing in faster than the bilge pump can pump it out. Under these circumstances, most sailboats quickly disappear under the waves, leaving the crew treading water. But what about QUIDNON?

Well, here’s the procedure. Unless the problem is relatively trivial—something that can be fixed with an oil-soaked rag, a hammer and a screwdriver—do not immediately deal with the leak because there are more important things to do. First, stop the boat. Raise the motor to the top of its well. Anchor if the depth allows, otherwise just drift. Close the watertight doors to the aft cabins (first making sure there’s nobody inside them); they will be used as emergency flotation. There are also large slabs of foam lining the walls of the engine well; as is usual, they have two jobs: 1. insulate against engine noise, so that the aft cabins are nice and quiet; and 2. provide emergency flotation when the boat is swamped.

Now you need to “blow the tanks,” just as you would on a submarine. Find the emergency SCUBA tank (it’s in one of the aft cabinets in the galley, strapped to the bulkhead) and open the valve on it. Make sure the regulator is set to somewhere between 15 and 25 PSI. Now do the following:

• Close all tank valves
• Open all drain valves
• Make sure vent valves are closed
• Open air valves
• Wait
• When you hear loud bubbling sounds coming from the engine well, close all drain valves and air valves. Close valve on SCUBA tank. Water tanks now provide 5 tons of additional flotation.

QUIDNON will now remain afloat while you effect repairs. When swamped, QUIDNON will sit low in the water, but it will not sink. The stuff that you don’t want to get wet should be stored in the aft cabins or on top of the water tanks.

The next step is to break out the emergency hull repair kit. It contains some canvas, a few pieces of plywood and MarineTex epoxy. Mix the epoxy, and use it to coat a piece of plywood large enough to cover the hole in the hull. Note that the plywood has kerfs (little slots) cut into one side, to make it bendy. When you put the plywood over the hole, the kerfs should face out, not in. Also coat a piece of canvas cut big enough to cover the entire area of the repair. Now go up on deck, dive overboard and apply first the plywood, then the canvas over it. Once the leak is stopped, start the motor (it may need to be partway up on its slide to keep the air intake above water) so that there is electricity for the bilge pump and wait for the water inside the cabin to be pumped out. Now fill the water tanks with seawater (to get your ballast back). Sail to some place where you can pick up some fresh water, then think about hauling out for more permanent repairs. The emergency repair needs to be ground off, the ragged hole cut out and replaced with fresh fiberglass and plywood, and the copper sheathing either hammered flat and reattached or replaced.

One last QUIDNON plumbing-related thing worth mentioning: there are three signal lights to tell you which of the three pumps is running, and three alarms, all wired up to a single bell, each with a silencer switch:

• Signal lights for raw water pump, fresh water pump and bilge pump
• Bilge high water alarm (means you have water coming in faster than the bilge pump can deal with it, or the bilge pump isn’t working)
• Starboard tank low water alarm
• Port tank low water alarm

The low water alarms are important because the tanks provide ballast, which is necessary for stability when sailing. Thus, when they aren’t full, this is something that the crew needs to know about. Of course, when the boat is drying out and the raw water pump isn’t running, the low water alarms are a bit of an annoyance, but they are there to remind you that you need to fill the tanks before you go sailing again. The silencer switches are important because in practice every alarm has a silencer, but if it isn’t a switch then it’s a mad person wielding a hammer or wire cutters, and that isn’t good for safety. Other signal lights are useful too. The bilge pump light tells you that water is getting into the boat from somewhere. If the raw water pump is running for no reason you could have a leak, a tap left open, a clogged strainer or you could be drying out at low tide. If the freshwater pump is running, you could have a leak, or out of freshwater, or maybe you left the bypass valve open by mistake, causing it to pump water in a circle.

To summarize, QUIDNON’s plumbing system will provide lots of tankage (you are unlikely to find another 36-foot boat with 1300-gallon tanks), all the usual amenities, plus a powerful safety feature that makes QUIDNON self-rescuing when holed and swamped. It achieves all of this functionality at minimal cost, thanks to the use of garden hose and fittings and RV instead of marine components. It is laid out in a way that makes it easy to work on. It is documented with schematics and troubleshooting procedures. And it will, I sincerely hope, prove to be conducive to preserving domestic tranquility.

Saturday, July 9, 2016

Progress Report

Much of the design work has been completed over the past few months. The 3D model, drafted in Rhino 3D, is largely complete. Construction techniques, including materials selection, joinery techniques and order of assembly have been largely worked out.

The cockpit design, the deck arches, the tiller linkage, tanks and lockers and many other details have been worked out in detail. We have designed a very strong structure for stepping the mast tabernacles, constructed out of 4x4 hardwood timbers glued and bolted together.

This structure, fastened and glued to the deck, bottom and sides of the hull, will also provide plenty of resistance to torsional loads, side loads when docked and strengthen the foredeck.

We are still working out such minor details as tiller design, hatches, interior cabinetry, wiring and plumbing, and running rigging.

The model has been hydrostatically tested using Orca3D software. (We are very grateful that Orca3D has agreed to sponsor our project, and has donated two seats of their excellent software for our use.) Hydrodynamic tests will have to wait until we build a 1:12 scale model, and conduct towing tests and other types of in-the-water testing.

The good news is: there are no surprises at all. The hydrostatic tests have confirmed the initial calculations: QUIDNON, ballasted as initially designed, is going to be seaworthy and reasonably fast.

Moreover, it will be able to carry considerable freight. Here is a table of draft (with centerboards and rudder blades retracted) vs. load.

Load Draft
0 12.9 inches
10 tons 25.3 inches
20 tons 34.6 inches

Shown above is the aft amidships section: two 20 lb. propane cylinders in an ABYC-compliant propane locker with an overboard drain, a 100-gallon gasoline tank below it, and a 40 hp outboard engine forward of it in an inboard outboard well.

According to results from Orca3D analysis, fuel consumption and speed will be as expected. As the above chart shows, even when loaded with 20 tons of freight, QUIDNON will do a comfortable 7 knots with a 40hp outboard at half-throttle, burning 2 gallons per hour, for a 350 nm cruising range. Without freight, its cruising range increases to over 600 nm.

It is interesting to note that when QUIDNON isn't loaded, as speed increases from 7 kt, power requirement shoots up. This is because the hull form is a compromise, and at 0 load the transom bogs down faster than when loaded. But this effect will be pronounced mostly when motoring; when sailing the center of force will be further forward, keeping the bow down and presenting a smaller profile to the water.

And so it is safe to conclude that QUIDNON will work very well as a live-aboard boat. You pay for a 36-foot slip and you get around 540 square feet of interior living space, plus just as much space on deck, which is plenty of space for living aboard and for throwing dockside parties. It is fast and economical enough to make a good canal boat, and with a 20-ton cargo capacity it can be used to bring back a year’s worth of harvest from wherever you hunt, gather or grow it back to your winter quarters.

But is it seaworthy?

But, you probably still want to know, Is it seaworthy? To an engineer, this is a fairly annoying question, because there is no technical definition of seaworthiness. And so I will apply my own definition. Seaworthiness is the ability to survive arbitrary conditions at sea. By “arbitrary conditions” I mean something that includes arbitrarily high, almost vertical walls of very angry water, with spindrift blowing from the wave tops at well over 100 miles an hour.

By this standard, few boats are actually seaworthy. We can immediately rule out all catamarans and trimarans: they are more stable floating upside-down than right-side-up, and once a rogue wave flips them over, it’s game over every time.

We can also rule out most yachts, large and small, with tall masts: once the masts hit the water, more often than not they snap off, and, again, it’s game over, every time. So masts have to kept quite stubby. In QUIDNON’s case, the masts measure exactly 36 feet from the mast tabernacle hinges, because they can’t overhang the bow or the transom when the masts are dropped and secured to the deck arches (for canal work, to pass under bridges). And the reason they can’t overhang is because that would increase QUIDNON’s overall length (LOA), incurring increased slip fees at marinas, and we can’t have that.

Secondly, we can rule out all large commercial ships: tankers, cruise ships, dry bulk carriers, container ships, etc. All of them are designed for a maximum wave height, and a big enough wave will capsize them, break them in half, or both. Over a hundred ships are lost every year in just this manner. But “fixing” this problem would be too expensive, and rogue waves are rare enough to keep marine insurers in business.

But we who sail around in small boats do like them to be able to survive almost arbitrary sea conditions. And if you try to design something that is completely seaworthy, by this definition, you end up with a coconut every time. But who wants to sail around in a coconut? (Actually, QUIDNON’s hull shape comes pretty close.)

Hydrostatic analysis shows that QUIDNON is self-righting up to 130º. It is very tender when level, and just walking across the deck is enough to make it list a few degrees. But beyond 10º it puts up a very serious fight. In fact, while sailing, it is probably not possible to make it list more than about 25º, in any sort of useful wind. It continues to put up a very serious fight until about 70º. Thus, any sort of sudden squall will lay it over for a bit, but with no serious consequences (unless you fall overboard, but that's verboten).

At around 90º, it gets ready for Round Two, because at that point the masts are in the water, and they are buoyant because they are filled with foam, weighing in at negative 8.5 lb. per foot of length, with a huge lever arm. Only beyond 130º does QUIDNON develop a propensity to turn turtle and settle.

When inverted, it is only about half as stable as when it is floating right-side-up, and if it lists by more than 50º it will right itself. Thus, if a big enough wave flips it over, leaving it floating at some arbitrary angle, there is only a 27% chance that it will be left floating upside-down. And if a wave big enough to capsize it comes along, there is about a 50% chance that the following wave will be at least half as big, enough to lean it over by at least 65º, and since 65>50, QUIDNON will then right itself. And so the chance of QUIDNON remaining bottoms-up after a rogue wave event is no more than 15%.

This, I would think, is quite seaworthy—for a houseboat. However, we must keep in mind that it is a houseboat, and even though we can take it out on the Big Wobbly with quite a lot of confidence, we should still remember that we are just moving house, not embarking on an extreme survivalist adventure at sea. And so, we should take certain precautions. These are divided into strategy and tactics.

The strategy is to avoid storms by carefully picking weather windows. For longer passages, on which storms are impossible to avoid completely, the strategy is to carefully pick weather windows for getting away from land, and for making landfall. The idea is to be nowhere near anything at all when bad weather hits. Rocks and shoals kill boats; wind and water—not so much. This is the sort of advice you can get from any number of books.

Another part of the strategy is preparing QUIDNON for bad weather, and it is QUIDNON-specific. QUIDNON can sail just fine with unstayed masts, but when making ready for the open ocean a bit of standing rigging makes a lot of sense. A triatic line is connected between the mast-tops, and two running stays are connected to each of the mast-tops and tensioned, the two from the foremast running forward, and the two from the mainmast running back. This set-up is traditional; Tom Colvin had lots of luck with this arrangement. Also, obviously, anything that could possibly shift in a capsize should be secured, both above and below deck.

The tactic is simply to ride out the weather, in the usual sequence: heave to, lie ahull, lie to a drogue, scud off under bare poles. Make a pot of stew, batten down the hatches and hunker down. Again, you can get this sort of advice from any number of books. Unless you are particularly unlucky, seriously bad weather generally passes in 2-3 days, and so with QUIDNON drifting at about 1 knot you’ll need about a 100 nautical mile offing from the nearest hard object to drift safely.

Since this is much more seaworthiness than one has any right to expect from a houseboat, and since it comes at very little additional expense (filling the masts with foam and rigging some running stays is pretty cheap) we will consider this aspect of the design handled.

Thursday, April 7, 2016

Mast Tabernacle Rethought

Sometimes delays are helpful because they allow more time for examination, and for rethinking parts of the design. And so it was with the tabernacle design. My initial plan was to use a joint that transferred all of the tension and compression loads into sheer loads on two large bolts, which I called “Jesus bots,” after the “Jesus nuts” that hold helicopter rotors in place. But then Alan, who is designing a boat similar to QUIDNON—a houseboat that sails, but for inland waterways—pointed out that my design would require extremely high precision in the way the components are fitted, or they would start to move and flex under load, and fail. Alan has lots of experience in aerospace engineering, and a keen appreciation for structural elements. What he proposed was two flanges bolted together, connected by a hinge on one side. This approach is very standard: look at your average streetlight, and that's how it's mounted. It is so standard that it doesn't require any interesting structural analysis: one can simply look it up and plug in the numbers. Since the bolts that hold the two flanges together are subjected only to tension loads, they don't need to be fitted precisely, and the math for sizing them is simple.

Alan's idea solved one problem but created another: how to fit the mast in place prior to raising it. He is used to working in a hangar, on land, when doing such things, but raising a mast on a boat in the water is a different matter. Precisely maneuvering a heavy mast on a swaying deck in order to insert the hinge pin is no easy matter. After much back-and-forth, we arrived at a solution. The hinge pin is welded onto the bottom flange—the one that's part of the tabernacle. The top flange has two slotted tabs that fit onto the hinge pin and two latches that capture it. And so all you have to do to raise the mast is get it into position and flop it onto the tabernacle. Click! After that, the procedure is simple: insert gin pole, attach hoist, and click-click-click until the mast flops forward. Then assemble and torque the flange bolts.

Another bit of very useful information Alan provided had to do with the design of the mast itself. I was thinking of using flagpoles, which are tapered, and of using them as unstayed masts. Alan tried to calculate the righting moment that would be generated by his hull in the event of a knockdown, and realized that such a wide hull would snap any unstayed mast. We also realized that there are a few other, minor problems with the unstayed design. The first is that there is nothing to prevent the mast from swinging side to side as it is being raised. The second is that the taper of a flagpole results in a sloppy fit up top, because the parrels on the junk sail have to be loose enough to be able to lower the sail all the way down. A straight, non-tapered mast would work better. Lastly, flagpoles are not the cheapest solution, which is to use 20-foot sections of 6-inch Schedule 40 aluminum pipe joined into the correct length for the mast using plugs made of smaller-diameter sections of pipe. The same pipe can be used for both the mast and the tabernacle.

And so the revised design has a mast tabernacle that uses flanges and a hinge, a mast made of straight 6" aluminum pipe, and two shrouds to at serve three functions: 1. prevent the mast from breaking in the event of a knockdown, 2. keep the mast from swinging side to side as it is being raised, and 3. take up some of the sideways load while sailing (which can be considerable, especially when sailing to windward, when the forward force is generated by two much stronger opposing forces of the sails and the centerboards acting at a small angle to each other). The design will remain unstayed as far as fore-and-aft forces are concerned, and the risk of dismasting from pitchpoling cannot be dismissed. Here, the addition of a couple of running stays, to be deployed fore-and-aft in particularly bad conditions, seems like a good idea.

There aren't too many options for shrouds on a junk rig. Since the sail slides up and down the entire length of the mast, there can be no spreaders. Nor are spreaders needed for a hull this wide. And so the two shrouds will run directly left and right between the mastheads and the ends of the deck beams that support the tabernacle at the deck, which are part of a trapezoidal frame made of hardwood timbers on which the tabernacle is stepped.

Problem solved... at least until somebody comes up with an even better idea, or finds a problem with this one.

Thursday, March 17, 2016

Deck Arches

QUIDNON has a large, flush deck, unencumbered by cabin tops, hand rails, vents and various other features that often makes sailboat decks far less useful. It can be used for lounging around in a chaise-longue or a hammock, for stacking bales of hay or cords of firewood, or for mounting various bits of equipment, such as plastic incinerators, digesters that produce gas for cooking or for running the engine, and biochar kilns. It can even be used to keep a few cages of chickens (for eggs and meat) and some small livestock (goats, for milk) tethered to the foremast. It is covered with aluminum diamond plate, for good traction, excellent wear resistance and to keep the boat cool by reflecting most of the sunlight.

The large expanse of QUIDNON's deck (measuring close to 550 square feet) is interrupted by two masts stepped in mast tabernacles, a large hatch in the center of the deck, and the dodger and cockpit aft. These elements are quite traditional; but there are also two more elements that are somewhat peculiar: there are two deck arches. They bear resemblance to boom gallows, but they are much more than that. In keeping with QUIDNON's overall design philosophy, they fulfill as many different functions as possible, to save space and to minimize costs.

The two deck arches are made up of three joined box sections—two feet and the arch itself—cold-molded out of plywood and fiberglassed on the outside. A thick plywood baffle runs along the centerline of the entire structure, to give it strength and to separate the airflows on the two sides. Along the front and the back of the arch there are openings, which can be closed and secured shut using internal sliders. On the bottom of each arch, in the center, is an eyelet for connecting a hoist. Where the arch joins the feet, there are diagonal reinforcements. At the tops of the arches are perforated aluminum angles (not shown) which can be used to attach an awning.

The arches serve the following functions:

1. Provide a point of attachment for a hoist. The front arch is used to hoist objects in and out of the cabin through the large mid-deck hatch. The aft arch is used to lift the engine out of the engine well.

2. Provide attachment points for the hammock or a swinging bench. This is an additional function of the two diagonal reinforcements in the inside corners.

3. Provide attachment points for an awning. The upper edges of the arches carry perforated aluminum angles.

4. Provide ventilation for the cabin. Front and rear sides of both arches have openings that let air either in or out, depending on wind direction. A baffle along the centerline of each arch keeps the two airflows separate until they reach the cabin, where they terminate in vents that direct the airflows in different directions, blowing air in and also sucking it out. They provide plenty of ventilation at anchor and on all points of sail except a beam reach. When sailing a beam reach in relatively calm conditions, the mid-deck hatch can be cracked on one side to cool the cabin.

5. Provide extra buoyancy up top in case of a capsize. The air openings on the front and back of each arch can be closed and secured using sliders, to create an airtight structure above deck level. Each arch encapsulates around 15 cubic feet of air. Both arches add around 2 tons of positive buoyancy 4 feet above deck level. This is very useful in case of a capsize, and enough to prevent QUIDNON, with its large, flat deck, from wallowing upside-down for any length of time.

6. Provide attachment points for sheet blocks (on top of each arch). A known problem with junk sails is that with most sheeting arrangements the sail tends to twist, losing efficiency, especially to windward. What typically happens is shown on the left; the optimal arrangement is what's shown on the right.

But in many cases this doesn't matter. For those who want to use QUIDNON primarily as a houseboat and prefer to keep things simple, a very simple sheeting arrangement will work fine, with a set of blocks mounted on top of each deck arch, while those who will want to make long passages to windward and would like an extra bit of speed can add a euphroe. I am also playing around with ideas for the ultimate solution: an automatic sheet traveler, but haven't tested it out yet. Here it is, shown schematically—not drawn to scale, and the final design will use tracks, sliders and blocks rather than rods and rings. But if you think hard enough, you should be able to puzzle out how it's supposed to work.

7. Provide places to mount navigation lights, red/green on the sides of the front arch, white aft light in the center, on the back of the rear arch.

8. Serve as boom gallows. When the sails are down, they can be made to rest on top of the arches.

9. Provide a support structure for the masts when they are down, for motoring down canals.

10. Provide an elevated place to sit or stand, to see a bit farther on the horizon and to be able to read the water better when sailing through shallows.

General progress update: There is now a full 3D model with most of the features drawn to scale, done in Sketchup. It has been moved to make a model in Delftship, which will be used for various calculations, and is in the process of being imported into SolidWorks, for creating a 1:12 scale model. There are plans to set up the model with radio control and sails, and to see how well QUIDNON sails.

Tuesday, February 9, 2016

Eye Candy

Many thanks to Helder Silva of Lisbon for making these 3D models in Sketchup.

Life on board is much too hard!
Full pilot house in the front, dodger version in the back

View from starboard quarter

Centerboards down

Meanwhile, down below

Centerboard pivot

Starboard water tank

Monday, January 25, 2016

QUIDNON Assembly: Stuff and Glue

When building a boat, no matter what technique is used, most of the time goes into making the parts. Much of the quality of the resulting hull has to do with the quality of the pieces—the precision with which they are fitted together. Much time is squandered grinding and trimming them to achieve a tight fit. All of this work requires some level of expertise, plus a well-equipped workshop.

This won't work for QUIDNON, which is to be assembled barn-raising style on some sheltered bit of coastline in a few summer weekends by people who have never built a boat before, and, if all goes well, never will build a boat again, boatbuilding being entirely incidental to the far more interesting activities of living aboard a boat and sailing it around.

Therefore, QUIDNON will arrive at the construction site in the form of a set of shipping pallets loaded with all of the parts pre-made. The kit of parts from which the hull is assembled will consist of a large set of plywood panels, milled out using an excessively precise numerically controlled machine. Each piece will be numbered, and each assembly step documented in a printed assembly manual.

The usual technique for assembling plywood-and-fiberglass hulls is to screw the plywood pieces to a light wooden frame using countersunk stainless steel screws while simultaneously gluing them in place with epoxy. After assembly, the joints are filleted using a bead of epoxy loaded with a special filleting compound. This is the so-called “screw and glue” method, and is known to result in a durable, long-lasting hull.

The choice of stainless steel is a compromise: stainless steel is not really stainless, and starts to rust as soon as it is deprived of oxygen. A layer of surface oxide called passivation is what gives it its stainless properties. It is unknown how well stainless steel fasteners fare when encapsulated inside a sealed wooden hull, where there is always the possibility that bacterial action will create an anoxic environment. Ideally, there would be enough osmosis happening, with water molecules migrating in from the outside and evaporating from the inside, and enough oxygen molecules would be carried along with the water to keep the stainless steel passivated. A safer choice would be to use bronze screws, but the cost of bronze is exorbitant.

Another, even better, and very cheap alternative is to use no metal fasteners at all. Instead, the plywood pieces are fitted together using a system of tabs and slots, all of them precision-milled using an NC machine. In instances where there is the possibility of making a mistake in assembly by choosing the wrong part, the joints are keyed using a unique combination of tabs and slots, making it physically impossible to assemble the hull incorrectly. The pieces are assembled in a certain sequence, which is made obvious by the consecutive numbering of the parts. After assembly, the joints are saturated with epoxy, then filleted to fill any minor voids and to bring each joint up to its maximum strength.

Several types of joints will be used.
  1. The simplest is the box joint: the edges of two pieces are made with complementary tabs, which mesh together in a rectangular zigzag pattern. This joint is used to join the bottom with the sides of the hull, and the transom, as well as in a lot of interior carpentry.
  2. Similar to it is the tab-and-slot joint: instead of teeth, one of the two pieces is made with slots that the tabs fit into. This joint is used to join the deck with the sheer clamp (the strip that goes all around the deck and is variously known as rail, or rubrail, or inwale, or gunwale, or bulwarks). In the case of QUIDNON, the sheer clamp has quite a number of duties: below deck, it is perforated by a row of holes for the deadlights that admit light into the cabin, covered on the outside by a strip of polycarbonate plastic; above deck, it holds scuppers that drain the deck and admit dock lines.
  3. Next is the zipper joint, which makes two pieces that are within the same plane act as one, by providing good strength under both tension and compression. This joint is used to join the sheer clamp to the sides, and to assemble the deck, the sides, the bottom and the transom out of separate panels.
  4. Next, it is sometimes necessary to have some tabs slide inside slots. Certain pieces of cabinetry need to be pre-assembled before being slotted into one panel while sliding in slots in another. Unmodified, this technique leaves voids, because the slots are longer than the tabs, and voids are a problem: they are hard to fully saturate with epoxy, can fill with water, get infested with mold and start rot. Such a sliding joint is also weaker than the others: if the joint fails and slips, then this can compromise the integrity of several other joints. The solution is to introduce a third piece, which locks the slip joint, filling the void and making it impossible for it to slip back.
  5. The last kind of joint is quite trivial. It is simply a shallow trough, used to position the piece that is joined to it at a right angle. It avoids positioning errors while making the joint stronger, because even a shallow trough (a single plywood veneer's worth) is enough to give the joint plenty of strength once it is saturated with epoxy and filleted.

The assembly process

The assembly team is best organized as two sub-teams: the stuffers and the gluers. These roles don't need to be gender-specific, although I suspect that in a lot of circumstances the stuffers will be mostly boys and the gluers will be mostly girls. The stuffers have to have good upper-body strength and some spatial reasoning abilities. The gluers need fine motor control and tidy habits. For the stuffers, all that matters is speed of assembly, since mistakes are made virtually impossible by the keying on all the joints. For gluers, the strength of the joints and the longevity of the hull critically depends on their attention to detail: all the joints have to be fully saturated, there should be no accidental drips of epoxy anywhere, and the fillets have to have the correct size and shape.

The construction then proceeds as follows. Most of the hull assembly happens with the hull upside-down.

• A stage is erected at a spot that is within 20 feet of the water at high tide, using straight dimensioned lumber and leveled using a laser pointer and wedges.
• The bottom, the sides, the transom, the bulkheads, the internal partitions and pieces of the engine well are assembled using zipper joints and set aside.
• The deck is laid down upside-down on top of the stage and assembled using zipper joints.
• Frames, of which there only two—one at each mast—are assembled next, and through-bolted to the underside of the deck.
• Internal bulkheads and partitions, and the engine well, are installed onto the underside of the deck
• Small brackets called knees are joined to the underside of the deck, going all the way around. The knees sit in shallow slots in the deck to make them easy to position.
• The first layer of sheer clamp is assembled by fitting it onto the tabs in the knees and pulling the joints together using straps.
• The second layer of sheer clamp is screwed and glued onto the first. The bottom edge of this layer (facing up during assembly) holds a zipper joint that joins with the upper edge of the sides and the transom.
• The sides and the transom are assembled next, pushed onto the zipper joints and clamped in place (this is where the stuffers get a good work-out). The sides and the transom mesh together using a box joint.
• The bottom is fitted on, joining the sides and the transom using a box joint. It is horsed on using tensioned straps.
• The joints between the sheer clamp and the sides and between the sides, the bottom and the transom are all saturated with epoxy all at the same time.
• The third layer of sheer clamp is screwed and glued in place.
• Tabs that stick out where the sides, the bottom and the transom meet, and around centerboard trunks, are removed using any number of techniques: a hand plane for the handy, a belt-sander for the well-equipped or a grinder for the those who like tools that have hundreds of uses.
• The centerboard trunks are pre-assembled, passed through apertures in the staging and the deck, propped into place and glued.
• Additional layers of plywood are screwed and glued onto the sides, the bottom and the transom to bring them up to full thickness.
• The bottom, the sides and the sheer clamp are fiberglassed using a layer of mat and 3 layers of cloth.
• The sides and the transom are faired using a lightweight fairing compound and sanded flat.
• Pre-cut copper sheets are screwed onto the bottom and parts of the sides below the waterline.
• The centerboards and the rudder blades are assembled, and the centerboards are installed
• The hull is flipped over. This is done by assembling a trapezoidal cage out of timbers, knocking out one side of the staging, and using a winch to roll the hull onto the cage, and then knocking out the sides and the top of the cage, leaving the hull sitting on just the bottom supports
• All the joints are filleted on the inside of the hull.
• The superstructure—two instrument arches and the dodger or pilothouse—is assembled.
• The deck is fiberglassed, then finished using pre-cut sheets of aluminum diamond plate, which are bedded with caulk and screwed into place.
• The hull is sealed with epoxy inside and painted inside and out.
• Polycarbonate plastic panels are screwed onto the outside of the sheer clamp
• Cleats, bow rollers and rudder post brackets are installed.
• The stage is reassembled as a slipway reaching under the hull. Four casters are inserted into holes in the chine runners, which rest in a slot in the slipway.
• The rudders, the rudder blades and the tiller are assembled.
• The boat is loaded with all of the remaining parts and supplies.
• The engine bracket is installed in the engine well, the engine is lowered onto it, and the fuel tank, battery bank and engine controls are installed.
• A line is secured to the boat, the bottom of the cage on which the hull rests is knocked out, and the boat rolls into the water.
• The crew climbs aboard, starts the engine and motors away from the construction site.

The remaining tasks—installing the concrete ballast and the mast tabernacles, the masts, the stanchions and the lifelines, rigging, plumbing, wiring, berths, cabinetry, galley appliances, etc.—can be completed with the boat in the water. While this is most easily done with the boat docked, but it's quite possible to do the work even at anchor, especially in a spot where it's possible to walk ashore except at high tide. It can remain in the water uninterruptedly for the next 30-35 years: the copper-clad bottom never needs painting, and there are no underwater through-hulls, propellers or other nuisance components to service.