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Anke and I live aboard WAYWARD, and wrote about it's design and construction at

Access to the net comes and goes, so I'll be writing in fits and spurts.Please feel free to browse the archives, leave comments where you will and write... I'll respond as I can.

Fair winds!

Dave and Anke
triloboats swirly gmail daughter com

Friday, September 16, 2016

TriloBoat Styles: Fitting Form to Function

Real style is never right or wrong. It's a matter of being yourself on purpose.
-- G. Bruce Boyer

If you obey all the rules, you miss all the fun.
-- Katherine Hepburn

TriloBoat Styles: Fitting Form to Function

As kids, my brother and I got a lot of mileage out of empty cardboard boxes.

Anything from apple to refrigerator boxes got taken to the moon (space ships), to the bottom of the sea (submarines), across the Great Plains (conestoga wagons), over Niagra Falls (barrels rolling down the hill in our yard). We cut windows and gunports and portcullises into them as 'need' arose.

Something must'a stuck...


I recently worked up StudyPLANS for a T20 side profile (MATCHBOX). By matching beam, super-structure, interior and gear to intended use, a builder can go in most any direction.

The above graphic, showing some approaches I favor for such a small vessel,  represents a pretty fair cross-section of the TriloBoat bestiary, to date.

Box barge hulls are exceptionally versatile foundations for tailoring to any nautical purpose. They carry loads well on stable footing, have lots of working deck and interior volume. Parallel sides ease construction (especially over the mid-ships deadflat) and make the most of their ends (think wide bunks, foredecks and cockpits).

All this, and relatively fast and inexpensive to build!

The approaches shown are just the tip of an iceberg of imagination, possibility and compromise. Innovate; copy; modify; shake 'em up; put 'em in a blender!

What might you do, given an empty box?


A few that got left out:




Idea for a container boat...
They dont HAVE to be boxy!


  1. That huge flat deck of B'Tugly looks super fun to play with. Imagine it as a 40X10 with standing headroom below and capable of a down wind run via the trades with awesome sprawl space once tucked inside some atoll somewhere. Or, given great insulating, up a backwater near London or Amsterdam for the winter with nice little heater inside. Relocatable world apartment with chaise lounge on deck. Yes...... 1001 possibilities with a box hull. Just plain fun to view your reveries on a box.

    1. Hi Bob,

      Open deck barges (e.g., B'TUGLY and SANDBOX) allow a 'flexi-space' approach that's very attractive to me, too.

      Interchangeable superstructure - whether solid shells or fabric - can configure the deck AND interior for a whole range of functions. Cargo today, party tomorrow, cruise the next month. 8D

      Dave Z

  2. I love the married with kids model. The ability to partition the little rascals into separate sleeping space is a most wonderful idea!
    I'm in my last steps of my steel triloboat planning. It's a t16x5 night fishing boat so will be rear half birdwatcher cabin and front end will be like the sandbox with low freeboard but set up for floundering with oars configured for rowing while standing near the bow. Plenty of sealed bulkhead will be included for floatation, storage and hull rigidity. It'll be junk rigged. The cabin section will be a flexispace cockpit with enough provision for warmth, cups of tea and sleeping if it just seems a better idea than pushing on. It should make a decent platform for snorkeling and fishing.I will also endeavour to add a BBQ to some part of it.

    1. Hi Tassiebush,

      They deserve their own space, wouldn't you say? 8)

      That's an ambitious design you're describing. Any chance of going aluminum to save weight? Make sure you calculate displacement and weights. Steel is better carried as the boat gets larger.

      SANDBOX has a raised foredeck (about 3ft above the bottom) over watertight storage... not sure that shows on the little sketch. Want to be sure of plenty of reserve buoyancy forward, to lift over oncoming waves.

      Sounds like a fun boat, though!

      Dave Z

    2. Thanks for your points BTW I think you just spared me serious heartache!

  3. I'm pretty keen on steel and lack knowledge and equipment for aluminium but I was thinking I'd use lighter materials higher up like the cabin. Hmm about reserve buoyancy that's a good point. Not sure I've factored that in enough. Don't want it to spear under waves. My thoughts were of an "unsinkable" vessel with enough sealed sections to float it with passengers and cargo but maybe it needs a fair bit more to not dunk down under it's momentum. Are there any conventions/rules of thumb on how much reserve buoyancy is required for vessel weight? I gather that you really need it concentrated at the edges of the boat against the rocking angles?!

    1. I don't know of any rules of thumb that would apply.... you've gotten over MY head, but a competent naval architect could advise you.

      In general, the reserve buoyancy will be the displacement of fwd compartments above the waterline, should they become submerged. That would counter mass/momentum of the hull running down the backside of waves and into oncoming ones.

      I usually just look at similar boats and how they perform/react. Unfortunately, there aren't many steel boats in your proposed sides.

      SLACKTIDE can ship green water over her 2ft above waterline bow if driven hard to windward (heeled over) in heavy chop. But she weighs close to 5 tons.

      Not sure what mean by 'edges of the boat against the rocking angles'...

      Perhaps you could write me at triloboats swirly gmail daughter com, and we can continue there?

      Dave Z

  4. Yet another..... standard with rockered bottom, steel grounding and ballast shoe on bottom, heavily crowned cabin, narrow at 5:1 L/B ratio...... speed demon and self righting.

    1. Hi Roberto,

      I've always been interested in 'whaleback' (i.e., highly crowned decks) as often used in lifeboats both for their looks and contribution to self-righting. Biggest compromise is that there's only a narrow strip amidships that's flat enough to comfortably walk on.

      Coupled with a 'hands-off' rig with all lines led to a secure handling location, that gangway becomes manageable, at least while underway.

      Dave Z