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design by Dave Zeiger davanke@yahoo.com

Essential statistics

LOA -- 15'0" LWL -- 11'6" (upright)
BeamMax -- 4'8" BeamHull -- 4'0"
SailArea -- 84sqft MastHeight --6'6" (AWL)
TrailerWeight -- 200 - 700lbs LTrailering -- 15'0"
Headroom -- 36"(under decks)
DispRange -- 500 to 1100lbs
DraftRange -- 4-1/2" to 7-1/2" (upright, add 1'3" for fan-up rudder)

Dave Zeiger

TRILOBYTE's brief is to be a skiff-sized ultrashoal-draft microcruiser cheap enough to be thrashable and encourage experimentation, light enough for manual propulsion and haul-out remote from facilities, allow rowing and sail handling from below decks, blow high blow low, and to sleep two adults side-by side. J

To accomplish all this, I started with elements from Phil Bolger's BIRDWATCHER and ADVANCE SHARPIE types, and applied them to a small barge hull. The barge's long, flat mid-section makes for a level work and sleeping platform with constant headroom. It maximizes the lateral resistance of immersed hull sides and 'hydraulic fences', while simultaneously eliminating drag induced when these latter follow a curved bottom profile (HFs are the lateral flanges extending off the hull bottom, p&s… used by Matt Layden on PARADOX and others). Symmetrical hull planes (formed by sides and bottom along the intersection of the chine) provide good tracking and steering (the cost is some tacking agility relative to AS hulls). A skeg adds a touch more, and protects a deeper rudder.

The high, polycarbonate topsides provide visibility, buoyancy and shelter (see Bolger's article, Wooden Boat #157). Waterproof (gasketed and doggable) oar-lock plates allow inside rowing without compromising full knock-down integrity when under sail. Ballast is live, relying on on-board knock-down recovery as a fail-safe, and positive buoyancy as the final back-up. This keeps weight down, but reduces ability to stand up to sail. Lead skids and/or multiple ply bottom courses may be added, but make haul-outs harder.

Crab-claw rig has seen a recent innovation (see hssrig.com), which renders it fully 'automatic' (Blondie Hasler's term for a 'hands-off' sail, completely managed via control lines). A yard spanning the two limbs of the sail pivots over the top of a short mast. Once rigged, all sail handling can be performed from within the hull enclosure. The sail may be oriented along three axes (mast, yard and centerline) and with the mast stepped on a longitudinal traveler, the CE may be positioned with considerable freedom. Rather than reef, excess power is directed upward, as lift, and, oriented horizontally, drive is neutralized (incidentally providing a rain/sun umbrella… longitudinal battens may reduce flogging, here). The lowerable CE and lift potential of the rig minimize heeling moment, important in a live-ballasted boat.

The main is supplemented by a small, triangular riding/storm sail to be set on the short mast. In a blow, the storm sail should provide a minimum of 45o off the down-wind, allowing some choice of cover or lee shore approach, and the mains'l may be used as a drogue. Anchoring is from the stern, rudder and riding sail reversed. I'd use block, tackle and rollers or skids to haul ashore (seaweed is a great lubricant, if it's handy).

The main hatch has a large lip, allowing a waterproof spray-skirt to be cinched on, kayak style. Similarly, one could sew in one or two anoraks under pocket flaps to allow upright rowing in the rain. The mast is booted, but water can work below via the rigging fairleads, fore and aft of the bulkheads. The bulkheads are unlimbered, and located at low points to help keep water contained. A sponge should be plenty to keep up with it. I'd store gear in waterproof bags, in any case.

TRILOBYTE's dimensioned around the materials… 1 foot high windows allow fabrication from one 4' x 8' sheet of polycarbonate. The sides and bulkheads are from 3 sheets of 1/4" plywood. Deck, bottom, transoms and hull flanges from 4 sheets of 1/2" ply… add two sheets if you wish to double the bottom thickness. I'd tack-and-tape the lower hull, framing the bulkheads and upper hull, and leave it unsheathed. The hard turn of the aft bottom may require thwartships kerfing, staggered between courses, and glassing. Rough and ready, it shouldn't take more than 100 hours, start to finish. Straightening the foredeck profile eases construction, but reduces reserve buoyancy, and hasn't that je'n sais pas quois. J

This version of TRILOBYTE favors shoal, light weight, human-powered exploration. Other priority sets dictate variations, such as a small outboard, more ballast, bigger sail plans, other lateral resistance schemes, etc.. I encourage experiment and customization. If there's any demand out there, I'll draw up a full set of plans, but try it… these hulls are perfect for beginning draftspersons. Scantlings as per Bolger (any of his design books).



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Two-line Biography:

My partner, Anke, and I are building LUNA, our Bolgeresque live-aboard in Tenakee Springs, AK. We plan to sail and drift indefinitely through SE Alaska.


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