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.

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.