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.

Wednesday, January 7, 2015

Nothing fancy

No, not like that...
This principle is really pretty simple, but the amount of money it saves is phenomenal. Most commercially built sailboats have the pretense of being little yachts. Yachts are supposed to have perfectly shiny smooth gel coat finishes or paint jobs that require waxing, like cars. They often have exposed, varnished wood on the outside of the hull called “brightwork,” and keeping it looking good is a constant battle, especially in the tropics. They have expensive stainless steel rigging and stanchions, and maybe even some fancy pieces of cast bronze. Inside, they have cabin soles (floorboards) of plywood made of teak and holly ($350 a sheet last I checked!) and lots of fancy hardwood cabinetry with fancy joinery.

The simple phrase “workboat finish” gets around all that madness, reducing the cost (and the fuss) by a very large amount. If the topsides are painted flat black, then you can use old car tires as fenders (free) instead of buying fancy inflatable vinyl fenders that make annoying squelching noises and tend to pop during storms. A deck surfaced with diamond plate works just as well as a teak one. In the cabin, simple plywood paneling and cabinetry painted in light pastel colors brighten the place up. Rigging should be galvanized steel, not stainless: it is more reliable and a lot less expensive.

Another powerful cost-saving technique is to avoid the word “marine” whenever possible. Any product labeled “marine” automatically results in at least a 100% mark-up. Often a supposedly “marine” product is simply a relabeled and marked-up version of a product designed for the RV market. This is especially true when it comes to plumbing, electricity and electronics, but applies to almost all kinds of hardware.

The list of such cost-saving techniques is almost endless, and practical people who live aboard boats accumulate long lists of them, and spend a good deal of time swapping tips on what works and what doesn't. Such little discoveries are a point of pride; after all, you never know what might work until you try it. Over the years, I've tried a lot of things that didn't work, and that's useful too, because it has kept me busy, and humble.


  1. $350 a sheet? No wonder things are expensive.

    Are there any places where having something named 'marine' *does* make sense? Marine grade plywood seems critical, or is it?

    I'm wondering if the markup is more at marine shops, since the clientele is generally wealthier. The food equivalent is shopping at Market Basket vs Whole Foods (Whole Wallet); some stuff is exactly the same, but WF is more expensive.

    1. I have found that some "marine" things do make sense. For instance, marine-grade stainless doesn't start weeping rust until a decade or two later. A few years ago "Chinese stainless" wasn't stainless at all, but now it is, and for some applications (exterior carpentry) I have found it to hold up just fine.

      Marine plywood seems critical for under the waterline and for parts that are regularly submerged. I wouldn't make centerboards or rudders out of regular exterior AC plywood either. For interior cabinetry I have proven it to not matter at all. I made a hard dodger out of doorskin (very thin softwood laminate) a few years ago, covered it with one layer of glass cloth on the outside, glass-taped it along the seams on the inside, sealed the whole thing with epoxy, primed it it with 2-part polyurethane sealer, painted it with 2-part polyurethane paint, and it has remained maintenance-free.

      For plubing, cooking gas, heating and electrical RV stuff seems just as good as (if not the same as) marine stuff. That's just a function of yachty people turning up their noses at anything labeled RV. For AC wiring, household stuff carefully chosen has been working fine for years.

      There are definitely two types of "marine" mark-up: clientele-driven and production cost-driven. It's possible to sort things out by looking at whether is something "marine" is used purely for recreation (conspicuous consumption) or also by people who earn a living on the water. So, when buying line, look at what commercial fishermen use. Same with most other supplies.

    2. A word from the cheap seats... Anke and I have had nothing but good experience with select AC (we pick through piles, avoiding voids and glaring flaws). We've yet to use a single sheet of marine.

      Marine has two A faces, and generally more plies (stronger/stiffer for a given thickness) and fewer voids (not always with US, deregulated marine ply).

      AC of good species, now made with same glues, does fine so long as one isn't engineering at the cutting edge of stress performance (i.e., use a little thicker AC).

      Marine is good stuff, no doubt. But AC ain't bad!

      Tips: Avoid even numbers of ply, and get the most plies for thickness available.

      Inject epoxy or LPU to fill voids, should one make itself known.

      Dave Z

      PS... Fishermen around here joke that marine ply is any found along tide line. Gets recycled, of course!

    3. We used 3/4" formply on our 37 foot sharpie build in 2003. The stuff with the orange paint around the perimeter. Tiny voids and nice stuff overall. Reuel Parker recommended it in one of his books. Doubled the bottom to 1.5" with roofing tar between and worked well for us. Cheap seats marine ply. Yummy.......

    4. Now two people—you and Dave—have confirmed that marine ply is pretty much gold-plating. Somebody should actually perform the "marine ply" test, which is to take a piece of ply and boil it for an hour. If it doesn't end up making plywood soup, then it's marine grade whether so labeled or not.

      For QUIDNON, replacing "marine ply" with "regular ply" saves a total of $13,000.

      Especially considering that all the plywood will be above the waterline, since below the waterline the hull will be cored with a reinforced concrete slab, this seems like a no-brainer.

      Thanks guys!

    5. The boiling test is to make sure ply doesn't delaminate if a coolant hose bursts or leaks nearby. You've already eliminated boiling coolant in another post.

    6. No, the boiling test is to make sure that the glue is waterproof and that the veneers won't turn into pulp when soaked. The boiling is just a way of accelerating the aging process. It has nothing to do with burst hot water pipes, which can still happen because there will be a hot water heater.

  2. First of all, kudos to you on this project and thank you for sharing the details of it with us.

    I'll be curious to see how well the galvanized holds-up in the salt water conditions. I agree 316L stainless is far more expensive (and can be brittle) compared to galvanized, but it has better anti-corrosive properties. Galvanized is cheap and less brittle, but I've never considered it in a marine situation. I would think galvanized would start rusting in very short order and would become a maintenance nightmare. How does the tensile strength of galvanized compare to stainless?

    1. Galvanized is all that is ever used on workboats such as fishing boats. They would never consider stainless. Galvanized steel is an "honest" material; it work-hardens, doesn't microfracture, and doesn't then fail with a loud bang. Galvanized does not rust until galvanization wears off, and hot-dip galvanized chain and and anchors are what everyone uses. (Haven't seen too many boats with stainless anchors or chain.) I think stainless is relatively safe, based on my experience, provided you oversize all the fittings. But that's a lot of money.

      Stainless is better than galvanized for standing rigging because it has lower stretch. But then that only matters for racers, and these days they are just as likely to use Spectra braid or some other fancy artificial fiber.

  3. marine vs "regular" is common.. our last sailboat had a Universal M25 engine. Marine parts are expensive, even oil filters. Turns it is really a re-purposed Kubota tractor engine with different alternator and water muffler added on. Cheaper parts at the tractor/auto store.

    Interior finish if you aren't real handy with wood working? Ikea, baby.

    $5/ft under mattress material to stop condensation? Bulk you cut air filter material at Home Depot for 1/5 the cost.

    Cannot wait to see more on your plan. You going to share the design layout?

    1. Exactly.

      Not so sure about Ikea, tbough. I haven't found anything boat-worty there except for throw-pillows for the cabin.

      I will make little study plans available as I go along. I might try to sell the NC tool paths though.

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  5. Since I'm setting out, still in the design phase, on the same path I will be following your blog with great interest. I got George Buehler's new book for Christmas, already had his previous one, and he has good things to say about medium density overlay ply otherwise known as sign board

    1. Please let us know how it goes. I've already figured out that "marine plywood" would be pure gold-plating, and not using it (especially since there will be no ply below the waterline) will save me on the order of $13k.