Collaborative Modular Project

Classic Repost:

With the feedback below in mind, and after thinking through my eventual “needs” for such a project, I’ve come up with a new cross section.

The bottom panel of the boat will be 8 feet wide.   The total width dimension will increase due to the thickness of the side panels added.  The width dimension above is nothing more than a scaling artifact.    The lower vertical panel will be 4 feet, to make the best use of wood and time as mentioned by Dave “” Zeiger below.   The upper panel is 3 feet, as that is a good non-fractional dimension that will optimize windows.  A 4 foot panel would make the boat too tall.

You may notice that I have done away with the flat roof.  While such a roof might of allowed a deck on top, I inserted a crowned roof for functional and esthetic reasons.  Later images will show how a deck could still be done.   Later drawings will also show how the base modules will still be able to connect end-to-end and side-to-side.

This cross section is, as it turns out, very similar to that of some of the triloboat designs.  It is also a cross section that is quite similar to some of the English canal boats.  Perhaps a good shape is recognized universally!

Once you add in all the stringers and such, it looks something like this.


I need to give credit to Dave “Triloboats” Zeiger once again, as once I found our cross sectional outlines were so similar, I drew inspiration from his framing.   This is also VERY similar to the way the escargot frames were made in my build.

Remove the stringers and panels and you get the basic module frame:


And more of the module being built… using four frames total.  No bottom stringers yet, and only half of the top of the roof installed.  Some details to clean up.


Sides in place, and floor.  No trim.


Two modules:

Three module Sections:

The method of joining modules is being developed.  Remember there will be stern and bow sections.  Ideas are welcomed.

And now three modules with identical bow and stern modules attached.


Original Post:

So many options. Build a few modules and then assemble them to meet your needs of the moment.

Our recent post about what we called the floating catamaran cottages got us thinking.   The idea seems so modular, and though it’s dimensions could be something like 10 feet by 24 feet, it could be a snap to trailer… if it was built with individually trailerable modular sections/pieces.   Then, as we set about designing the core module, a great number of variations became apparent.

So what ideas do you have?  We will share them here in a series of posts.  Make comments below and/or send your drawings or ideas to shanty@shantyboatliving.commm (But remove the spam fighting extra “m”s.)   These drawings were done within an hour, quick sketches with a few flaws, but perhaps inspirational ones.   What are your ideas?

The original inspirational idea.
Two core modules joined end to end, with a deck/ama module. Add on one side or two. Add bow or stern modeles, or not.


In this example each of the two modular cabins are 8 feet wide by ten feet long, making each of them easy to transport on a modest trailer.  Then add a couple of 22 foot long beams, perhaps made of three overlapping sections, none longer than 10 feet, that could be assembled on site.   Finish the design with a few deck sections, maybe ten feet by four feet.   Or so go some initial sketches on the back of a Google Sketchup “envelope”.

One version of the core module, for a boat, barge, raft home, small rv trailer. . Probably a bit too tall at this point. Sides could fold up as a “roof” over a deck attached along side… panels doors could slide open. And……?


Add bow and stern modules to one, two, dare we think three core modules. Perhaps an outrigger module or two would help at that point.

Share your ideas below.. and send your pics to the email above.  (To avoid any legal hassles or confusion we will need to say…”all submissions become the property of as ideas may work their way into future designs or plans or postings.”)

4 or more modules build quite the home, yet one that could be easily built in a garage, then transported to the launching sire where it would get final assembly.

Originally posted 2012-07-01 07:22:33.

A website about Shantyboats and affordable living on the water. More than 800 stories to date, and growing.


  1. First of all… COOL CONCEPT!!!

    A couple of suggested adaptations for ply usage…

    I’ll call the flat between arcs the ‘roof panel’, and that between roof panels of partner modules the ‘fill panel’.

    If you make the roof panel an even 4ft centered on it’s 8ft module, the fill panel will also be 4ft with no filling (as drawn, the gap is wider than 4ft). Whole sheet construction is much less work. This assumes that the hulls FINISH 8ft and are butted cheek to jowl… preferably bolted into a single monohull (bumpers or chafe gear would spread hulls and allow independent motion).

    Eliminating flare in the pontoons (rectangular sections) will reduce labor, waste and increase displacement and stability. In general if you can design around whole, half, third and quarter panels, you’ll save oodles of time and money.

    Consider running side panels vertically, from the bottom of the hull to the top of the arced in panel (living on the inside of the bottom, or up to a 1ft raised sole). This allows 4ft modularity for length (4, 8, 12, 16ft, etc) with full panel construction. Can be modified for half panel construction.

    Alternatively, two courses of 4ft, laid longitudinally gives a 4ft hull (all angles rectilinear from that point down, curved panels above). Keeping rectangular, low, eases building the interior.

  2. Thanks. All above makes total sense.

    What about rocker? These modules are flat, flat, flat. The box and stern sections could provide some shape, but just for their length. That appears to be the layout of all your designs, and they are ‘real world’ proven. Should be ok.

    In the drawings above there are lines that are there to help with windows, or show where a door could exist. They don’t show plywood layout. But your points are very well taken. When I dive in again I’ll keep total modularity, if that is a word, in mind.


  3. Rocker does add some ‘slipperiness’ to the hull, but relatively little. It adds a lot of time, effort and waste, and impacts the interior… need a false, flat floor, or live with the curved inner hull. Also, rockered bottoms are a step more difficult to move and secure for trailering.

    These guys are likely to be largely stationary, with only slow or current assisted transitions by water between moorings. I’d recommend leaving the core modules flat and rectilinear.

    If more shape is required (for a longer journey, say), ends may be added to streamline. These could range from inexpensive shells to fully developed hull sections, as need warrants.

  4. I have one serious complaint about this site, Bryan, and that is that there is SO MUCH material here and there are SO MANY ideas to give food for thought that it could be a major job keeping up with the new stuff and commenting on it! That is one reason I have not contributed much, but I am going to try to pick and choose, and hopefully make a few more comments… KEEP UP THE GOOD WORK!!! Seriously, this place is a wonderful resource for those of us looking at and planning towards living inexpensively on the water. Thanks so much!

    I second Dave’s remark about this being a really COOL CONCEPT!

    Now, I am going to break down my remarks here into several posts, to keep them better organized and “bite-sized.”

    re: Bob Walker’s query, I would simply say that the essential concept of a shanty boat is affordable shelter afloat in which to live (either permanently or temporarily). Traditionally (and in many cases nowadays), the least expensive way to get such housing has been to build a simple raft or barge (depending on the materials and funds and time available) then put a little house/shack on it. A shantyboat becomes a barge or a raft (depending on which kind of “hull” has been used), when the house or shack is removed. That is, the emphasis is on “shanty” meaning affordable shelter, and not so much on what supports it in the water.

    One question to explore is that of legal definitions for purposes of titling, registration and taxation. At what point does a raft become a boat and need to start complying with all manner of state regulations for registration, etc.? I suspect that varies a lot from state to state, but I also suspect these days most things that float with people aboard are considered boats, regardless of whether they have motive power or not.

  5. re: modularization concepts

    I agree with pretty much everything Dave said in his first post, with a few comments.

    For my purposes, I look at a “shantyboat” in three somewhat different ways, all of which appeal to me a lot. I am aiming towards moving aboard in 4-5 years, and I simply have not decided yet which concept appeals to me the most. And I also consider that with the current interest in shantyboats, there may develop more of a shantyboat culture in the next few years which could influence the direction I take. Anyway, the three basic concepts I am looking at are 1) a small liveaboard boat suited to coastwise cruising and/or the Great Loop, 2) a small liveaboard boat which is intended to stay in one location most of the time and occasionally move a few miles for a change of scenery, and 3) a liveaboard “boat” of the second type which is intended to raft semipermanently with similar craft owned by likeminded friends in an intentional community (like the “Tranquility Base” article posted elsewhere here).

    For the first type of craft, I might consider a modular concept, most likely in the longitudinal direction only (sort of like the MacNaughton Group’s Eventide “narrowishboat” concept). In that sort of design, I would consider using flared bilge panels or topsides as in Bryan’s original pictures (and I will not argue with Dave about stability or anything else… I know flared sides involve tradeoffs, I think it looks prettier flared, and I am happy to accept the consequences!).

    In the second and third types I described above, I agree completely with Dave – square boxes using standard plywood dimensions (or fractions like 1/2 or 1/3 where needed, though those do add work) make the most sense and have little to no downside.

    Now, for module sizes and types, I suggest first of all that the hulls and superstructures be considered separately. It is certainly possible to build a hull module with its sides extending up to cabintop height and close it over the top, but as Bryan drew things that assumes the cabin is flush with the sides… what if you want side decks, or a side deck on only one side?

    Consider building the hull modules as open-top plywood boxes 8′ wide and 2′ deep, with 2x construction lumber in all corners. I like the boxes 8′ long as well, but 12′ or 16′ sections are certainly possible as long as you do not mind scarfing or butt-joining the plywood sheets (and of course there is one butt joint needed on the bottom and deck of an 8′ module anyway). Now a simple framing choice allows you to add a deck at the top of the box or halfway down inside, or no deck at all (walk on the hull bottom), and a slightly more complicated framing allows recessed interior decks with side decks at full side height.

    As for the deckhouse structures, my first impression of Bryan’s curved-sided modules was that they looked like a vardo or a Conestoga wagon, and I began thinking about building a fabric-on-bows house with insulating quilts hanging inside. I still like the idea, but for a more conventional approach one could fabricate framed and insulated panels in several sizes and shapes (including a curved one), which could be quickly glued and screwed together as desired at the waterfront.

    It’s time for bed now, so I will add a few more thoughts in another post tomorrow (well, today, but after I sleep!).

    • Hi Samantha,

      There’s a raft in Tenakee Inlet with a Pacific Yurt ( mounted. Various folks have been living aboard, year round, for many years now (we were at the raising, early 2000s?). Got me thinking about fabric structures.

      I like your Conestoga comment, and think that’s an inexpensive and versatile way to build.

      Dave Z

      • Thanks, Dave. I’ve always been fascinated by nomadic and semi-nomadic lifestyles, and the housing choices that went with them. Tents, teepees and yurts, covered wagons (including Conestogas) and vardos have been some of my favorites. Kayaks, too, as the boat equivalent. Then a couple of years back I discovered the recent surge of interest in skin-on-frame boats, and now I find that concept of a relatively light framework plus a waterproof fabric skin is never far from my mind, both for boat hulls and living shelter whether on land or water. So when I saw the curved upper panels of Bryan’s initial modules it seemed a natural application for skin on frame – strong, light, inexpensive, weatherproof panels with organic shapes that are translucent to admit sunlight and can be insulated effectively with quilted hangings.

        I have a lot more to share about skin-on-frame, so will probably need to write a new article about my ideas. And I really like pretty, sexy sailboat hulls, so these boxy boats are a big departure for me… but I have to tell you that I was reading one of your articles a few weeks back and I was looking at Slacktide, and I thought, “what a cute, attractive and sensible boat!” You may win me over yet (with a little posthumous help from Phil Bolger) to the square boat tribe!

        — Sam

  6. Bryan, I like the new sketches! I look forward to seeing what you have in mind for joining two units side-by-side or with a deck between them.

    In your original concept sketches, I found myself both bothered and intrigued by the large V-shaped “grooves” that would form when two modules were put side-by-side. I was bothered by it because it seemed like a large empty space would be wasted… but then I wondered if that space could be sealed by the deck over, the end wall pieces and by securely attaching the lower walls together. We would then have an awkwardly-shaped space at upper-cabinet height… cut some access panels in the curved upper wall sections, add some shelves in the V-shaped space, and we have something akin to the overhead bins on airliners. It might be a great place to stow bedding, clothing and linens, among other lightweight items.

    To join modules together permanently, couldn’t we use bolted and glued butt joints between units? Use drilling templates to predrill the end (and possibly side) framing lumber with a standard bolt pattern, then join the units at the assembly site with epoxy and bolts.

    Regarding rocker and end shaping, there is no point in shaping the “building block” modules unless one intends to move the completed structure regularly over significant distances (as in cruising). And even then, Dave has amply demonstrated that a rectilinear hull with simple rake ends can work just fine. The main concern at these low speeds is just to avoid immersed transoms that push a lot of water aside at the bow and drag a lot of turbulence behind the stern.

  7. I am worried by the flat bottom. From experience I have learned it is almost impossible to bail small amounts of water from the hull. This is a problem both during the building if not well covered and after launching. Some water always seems to find its way in and stay in. I would favour some rocker like the Bolger design which collects water at the center. The curved tension also helps bottom stiffness, john bartlett

  8. Delightful concept.
    Another article that inspires ones (feeble) handyman skills.
    Or at least brings hope that living on a boat is doable, and won’t kill your budget.
    Thumbs up.

  9. Maybe t-slotted aluminum could be used as structural supports:

    This would make the superstructure easily modifiable (if more expensive).

    These barrel bolts may also be helpful for building modular furnishings:

    Have you heard of Ephemerisle? This structure would be ideal for the event:

  10. Use my 14′ hexagon “greenhouse” frame on a hexagon extrusion welded plastic “barge”.
    Frame is 2×2 wood, but could be done in aluminum square tubing.

    Open Source Greenhouse – YouTube –

    Dura Poly Commercial Barges and Work Boats –

    Hexagons are wind shedding…and they tile together most efficiently.
    You can cover my frame with insulating pink/blue boards a-la the Hexayurt (Google it).
    Coat with white elastomeric roof coating.

    The “barge” could also be made from 1/2″ thick ferrocement shell…then fill with low density floating cellular concrete.

    I’ve got Sketchup models of all this stuff done already.

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