Slingshot 19


• Top Speed (typical) = 14 mph
• # Of Occupants = Two
• Length Overall = 18’ 10”
• Beam Overall = 12’ (with fixed akas) or 14’ 6” (with folding akas)
• Main Hull Max Beam = 24”
• Length Of Amas (outriggers / floats) = 18’
• Weight Of Main Hull 125-150 lbs (57-68kg) depending on plywood choice
• Weight Fully Rigged = approx. 225 lbs (102kg)
• Draft Fully Loaded = 5” max
• Sail Area = from 107 sq ft (with base rig) to 155 sq ft (with sloop rig)
• Sail Rig Type = several options, both stayed and unstayed (freestanding)
• Mast = aluminum tubing, either unstayed or stayed (freestanding)

The‘Slingshot 19’ is basically a 2-seat version of the ‘Slingshot 16’ trimaran. We offer plans for this 19’ boat because we have received so many requests for a 2-seater. It is approximately 15% bigger in all dimensions than the Slingshot 16, and is about 40% heavier. It has a wider beam if you go for the optional folding aka, and can carry significantly more sail.

The two biggest factors in deciding to go with the Slingshot 19 (vs the smaller Slingshot 16) are:

1. The Slingshot 19 is a two-seater, so you can sail it either alone or with a passenger. The primary seat slides to one of three positions, to keep the boat in perfect balance with either one or two aboard.

2. With the Slingshot 19, you get the option of having straight one-piece tubular akas, or a proprietary “folding” aka system. With the folding akas, the amas swing in alongside the main hull so you can quickly reduce the overall beam from 14’ 6” to just 7’. Launch time is also greatly reduced.

Lots Of Options!

- You can build the Slingshot 19 with either straight, one-piece akas (crossbeams), or with folding akas for easy trailering and quick setup.

- You have the option of an great variety of sail plans, ranging from a 107 sq. ft. cat rig to a sloop rig with more than 150 sq. ft of sail.

- The plans include detail drawings for five different sails, and two different folding aka arrangements.

A Solid Performer:

The top speed (observed by me) is 14 mph, just as with the Slingshot 16. But the Slingshot 19 is smoother, quieter, quicker in light air, handles rougher water, and just “feels more stable” in virtually all conditions. I also have adapted a side-mounted motor mount and often bring along a small outboard, just in case the wind dies.

Just like the Slingshot 16, the 19-footer points higher than 45 degrees, and turns on a dime. It can be launched in 4” of water and sailed away - upwind - in just 6”. And as with the Slinghsot 16, the plans for the Slingshot 19 are the result of a joint effort between myself, as the primary designer and builder, and Andrew Walters
( whose awesome CAD drawings compensate beautifully for my own sad lack of drawing ability.

And if you’d like to see what these little tris are capable of in just 10 or so mph of wind, here’s a link to my ‘Trimaran Action Video’ featuring one of our 16-footers equipped with a 95 sq. ft. vertical batten sail I designed and built.
Basic Materials List:

- (6-1/2) sheets of 6 mm ply (recommended for all main hull panels)

- (5) sheets of 3 mm ply

- (½) sheet of 1/2” ply (This plywood should have 4 or more plies)

- 8 linear ft. of 1” x 6” lumber (3/4” x 5-1/2”) clear or nearly so

- 80 linear ft. of 1”x2” lumber (3/4” x 1-1/2”) clear or nearly so

NOTE: The original Slingshot 19 (and amas) seen in these photos was built from plywood (3mm and 6mm) costing about $12 and $21 a sheet, respectively. You can also spend the extra $ for okoume or some other pricey species of plywood. As long as the glue is waterproof, you can use any ply you wish.

Plans Include:

- Three extremely detailed construction manuals with a total of more than 240 photos illustrating the complete building process, with nearly more than 10,000 words of explanatory text by Frank Smoot.

- A separate manual with more than 100 superbly detailed, multicolor CAD drawings by Andrew Walters.
‘Slingshot 19’ Trimaran:

- Full Build Plans: $145 at
- Study Plans: FREE at

Design Specs

Frank Smoot
Year of Design: 
18' 10"
Open = 14' 6", closed = 7' 6"
225 lbs
sail, small outboard
Skill Level to Build: 
Available as: 
Complete Plans