L20 Beach Trimaran

L20 Beach Trimaran 2017 Foil




A modern Trimaran deeply rooted on western Pacific double outrigger “Bangka”. Its basic structural elements are comparably the same, but the shape and construction method are relatively new, to take advantage of modern materials and engineering.

This wood-epoxy-fiberglass composite boat uses 5mm thk marine plywood in Stitch & Glue construction. The hulls are multi-chined to conform an oval cross-section. The crossbeam “Aka” are shaped S&G shell with internal structural members and flanges for bolted or lashed connection to the hulls.

The one-piece Akas are demountable for ease of transport and storage. These 4.8 meter (16 ft.) Akas are designed as standard parts, that can be mounted on different hullforms for a specific intended use. Included in the Aka-set are trampoline, 2.1 meter (7 ft.) long seat, and hiking bench. The Akas are mounted 2.4 meter (8 ft.) apart on centers.

An Ama is 16 feet long with a buoyant force of 180 kgs when fully submerged.

The 6 meter (20 ft.) long mainhull “Vaka” has a displacement capacity of 395 kgs at designed waterline of 300 mm (12 in.). This should be enough for 4 people with gears on a weekend camping.

The mainsail area is 16.61 sq. meters (178.8 sq.ft.) while the jib area is 5.33 sq. meters (57.4 sq.ft). The rotating wingmast height is 9.14 meters (30 ft.).

July 2017 Update

I started this trimaran design way back in 2011. I was very excited when I got good feedback from the boatbuilding community, that I started building the Aka while trying to complete the drawing details of the boatplan. Determined to complete the trimaran, I took a few commissioned “short duration” boat projects to help finance the cost of materials.


The supposedly quick builds turned to years… until I totally forgot it and was ready to scrap the idea when another “house” building project came by again.

Six years quickly went by, and finally, all the distractions was over. Now I am scampering to retrieve the drawing files and re-study these all over again.

Over the years, I missed a lot on new boat tech. I’m in awe to realize that the new breed of multihulls are now “flying” on hydrofoils.

“I think I can work out this flying fad!”

I updated the drawings to a “raked” bow shape on both Vaka and Ama hulls. The Amas now are 18ft in length, with increased buoyancy of 202 kgs. I will work out the hydrofoil design and will add them later in the final stages of the build.

The current layout of this trimaran is a daysailor, but since the “side” seats can be totally removed along with its conventional centerboard and rudder. The foils can transform this boat like a water strider bug.

Boat Plans are now available for this Trimaran

L20 Beach Trimaran - Sailing Rig Comparison

The concept behind the L20 Trimaran is based from Paraw. Traditional Oceanic Sprit sailplan is included in the construction plans.