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.

Friday, January 30, 2015

Construction plan

This will be the last post in this series. The design of QUIDNON is far enough along to start entering actual engineering drawings into CAD. The plan is to use an NC mill to cut out quite a lot of the plywood shapes. To be sure, there will still be some pieces that will end up being precision-fitted using a Sawzall and a grinder.

The main assembly technique is what's known as “glue and screw”: some piece of the hull is covered with a thin layer of epoxy, and the next piece is laid over it and screwed down using square-drive stainless steel screws. Each piece to be screwed on is pre-drilled with countersink holes, so that the screws pull the pieces together very tight, squeezing out excess epoxy and creating a very tight bond.

Once the plywood shapes are cut out, construction will proceed roughly as follows.

1. On a large flat surface (preferably a hangar of some sort, with a concrete floor), the outer layer of panels that will make up the perfectly flat deck will be laid out, inner side up. The deck will be made of 18 4x8 panels of 3/8 plywood. Nylon straps will be laid underneath the plywood, to make it possible to pull the hull together, and to lift it by crane when the time comes.

2. The inner layer of panels that make up the deck is then glued&screwed to it. These panels are laid out so that the joints are all staggered nicely. The inner layer's edge is in 1.5" from the outer layer, creating a ledge. The ledge is scraped clean of epoxy after it sets but before it hardens.

3. The first deadlight strip is glued&screwed to the underside of the deck, all around, using the ledge as a guide. The screws are directed at a 45° angle down. Two more layers of deadlight strips are laid down, building up the thickness to 1.2". These are precision machined so that the deadlight holes match up. The outermost strip is 1" narrower than the other two, creating a ledge, which is scraped clean of epoxy.

4. The innermost layers of the topsides, the bottom and the transom are glued&screwed together, using 6"-wide strips of epoxy to cover the seams on the inside, and laid aside.

5. The bulkheads are assembled and framed using fir 2x4's, which are cut to the right bevel using a table saw, and glued&screwed to the underside of the deck.

6. The pre-assembled topsides and transom are maneuvered into position and glued&screwed to the deadlight strips, using the ledge as a guide, but the screws are not yet tightened.

7. The pre-assembled bottom is overlaid over the bulkheads, maneuvered into position, and screwed down at the bow.

8. The sides and the bottom are pulled together using straps and bits of angle iron to align the chines. Open stretches of the joint between the topsides and the bottom are saturated with epoxy. The screws joining the topsides to the deadlight strip are tightened, and the epoxy is allowed to set.

9. Once the epoxy has set, the straps are removed and the places on the chines which they masked are saturated with epoxy. The inside corner of the chines is filleted with thickened epoxy.

10. The hull is built up by glue&screwing additional layers of plywood to the topsides, the transom and the bottom. After each layer is added, the chines are fiberglassed with a layer of fiberglass tape.

11. Once the hull is built up to full thickness (3 layers of 1/2" plywood all around, 4 at the bottom). The chine runners are built up. The outermost layer of the bottom contains chine runners, to which additional crescents of plywood are epoxied and glassed to build up the chine runners to a 2" thickness.

12. Fiberglass mat is nailed to the topsides using bronze annular nails, saturated with epoxy, and ground off along the deadlight strips and the chines.

13. Three layers of fiberglass cloth are draped over the entire structure, deadlight strips included, and saturated with epoxy.

14. The bottom is barrier-coated, then bronze sheets are laid on the bottom and screwed down, each screw bedded with 3M 5200.

15. The topsides and the deadlight strips are faired and sanded for a flat surface, then primed and painted. The topsides are painted black for the best passive solar performance. The deadlight strips are left with the bright white primer, because they will be overlaid with bronze lexan which will give them color.

16. The hull is flipped over. The deck is covered with fiberglass mat (nailed down with bronze annular nails) and saturated with epoxy.

17. Three layers of fiberglass cloth are draped over the deck and saturated.

18. Aluminum diamond plate is overlaid on the deck and screwed down with screws bedded with 3M 5200.

19. Deck beams and gunwales (which are steamed out of solid hardwood) are lag-bolted up through the deck and to each other, sealed with epoxy, primed and painted.

20. The hull is now complete, ready to receive the pilot house and the cabin can be outfitted.


  1. Hello and thank you for sharing, I have been following your writing for a long time. I will be spending some time this summer in the coastal Carolinas, any suggestions on a few (cheap) building sites, marinas, industrial parks along the ICW.
    Again thank you. (I hope this is not a double post)

    1. I'd be interested in hearing about it as well. My basic requirements are:

      1. A flat piece of dirt that I can build a deck on using cinderblocks, 2x4s and oriented strandboard.
      2. A place to put down a half-size shipping container with the supplies
      3. Either a cheap room or a trailer or a boat (hauled out or floating) to live in within bicycling distance

      Has to be close to water. QUIDNON is a single-wide and would need a highway permit to travel any distance, plus the expense of hauling it. So, ideally this would be in a boatyard.

  2. Sign me up for the build. This looks awesome.

    When do you want to do this; how long would it take? Would doing it near like minded folks (the folks who built the Ceres) be helpful? Or would that be a 'too many cooks problem', or not enough time (since they are in VT)?

    Having some locals who have some tools you need might be a big help, rather than purchasing for the build specifically, unless you have all this stuff.

    1. The timing of the build is uncertain. I will have to see how things develop. Of course, building several QUIDNON hulls in tandem would be very helpful, and there are economies of scale in milling all the plywood panels for a few hulls together. Once the hull has been built, it can be launched, and everything else (pilot house, ballast, masts, cabin liner and insulation, furnishings) finished with the boat floating at a slip. If most of the hull pieces are prefabbed, putting the hull together is a fairly quick procedure, and goes quicker with the number of people. So it is possible to use a single building site to glue&screw together a bunch of hulls, set them floating, and then finish them in parallel. So there would be a batch of ballast pours, a batch of water installs, a batch of tabernacle and mast installs, etc. Optimistically, next summer would be a good time to start building, but we'll have to see.

  3. In the interest of cost savings, consider getting away from the East Coast. Since this is a shallow draft design, you might have better luck up a river nearby, or next to a tidal estuary that only permits transit during high tides. However, this might mean renting close to a swamp-like zone. Alternatively, the West Coast of Florida might be economic during the winter.

    1. Sure, the the build can happen at some unfashionable spot in a tidal estuary. As long as there is a Home Depot within an hour's drive.

  4. Hi I have a really dumb question regarding the pilot house, could it be moved between the 2 masts or just in front of the main, I will not list the advantages I am thinking of, and I realize the biggest disadvantage is passing through it going fore and aft. Just looking for opinions. Thanks.

  5. Sure, that's a possibility. There are a few complications.

    1. The boom gallows has to move aft, and the ducting it requires to also ventilate the boat becomes more complicated.
    2. The steering shaft gets to be a lot longer.
    3. The engine well is now really far from the wheel, requiring longer control cables.
    4. The companionway hatch is outside the pilot house and needs a more substantial box and a dodger to keep water out.
    5. When the companionway hatch opens, all the heat from the cabin escapes to the great outdoors instead of warming the pilot house.
    6. The skylight in the pilot house doesn't give a good view of the leach of the mainsail, making sail trim more difficult.
    7. There isn't enough room on deck to store dinghies.
    8. There isn't enough room for the centerboard purchase to work.

    1. LOL that's quite a list, all legit of course, workarounds would require a different interior layout among other mod's. Based on your extensive ocean voyages, how important is the need to make the pilothouse completely sealed and waterproof to add buoyancy in case of a knock down

    2. Oh, left out a couple:

      9. Can't use boom gallows as a place to hang a hoist to move cargo in and out of the hold using the deck hatch, which would be gone, consequently

      10 Much less light in the center of the cabin.

      On the plus side,

      1. The buoyancy of the pilothouse would be centered above the center-mass of the boat, which would be helpful in a knockdown

      2. There would be a large poop deck, so potentially you could have 4 completely separate parties going on all at the same time: foredeck, pilot house, afterdeck and cabin. Plus whatever action is going on in the aft cabins.

  6. Thanks for letting us play in your sandbox. I enjoyed it tremendously.

    1. You are very welcome. It was a fun and useful exercise.

  7. Will you be documenting the build online?

    1. Yes, definitely. I won't be posting every day, but there will be posts on the CAD work and the NC machining and other things even before the build begins.

    2. Thank you, I look forward to it.

  8. Is the price of 8x 16' plywood panels prohibitive? Not as common. But it would reduce seams.

    1. I haven't checked. The problem is that the NC machine I sort of have in mind for this job takes 4x8 sheets. Also, 8x16 sheets are an absolute pain to maneuver, and if you screw one up you've screwed up 4 times as much material.

  9. Hi and thank you for sharing this wonderful dream with us.
    I have questions and comment on the search for a suitable location for the build out. Would you like me to post here or maybe add a new post heading: “location”