Model: Length: Hull Weight: Beam: Max Payload: Rowing Draft: Sailing Draft: Sail Area:
Lake Union Swift 10' 0" 150 lbs. 52 in. 450 lbs. 6" 30" 78 sq ft.
Lake Union Swift Configurations:
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Standard Configurations:
Lake Union Swift - Base Hull Kit
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$2575
Alternative Configurations:

Sailing Component Kit - Sloop Rig
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$3849

Sailing Component Kit - Lug Rig
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$1895

Lake Union Swift - Wood Parts Only
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$1880

Lake Union Swift Full-sized Plans and Builders Guide
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$219
$197

Builder's Guide Only - Color Print
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$35

Builder's Guide Only - Emailed PDF
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$30
$27

Study Plans - Emailed PDF
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$2
$2
Additional Components:

Sail Package - Line & Cordage - Sloop Rig
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$125

Sail Package - Line & Cordage - Lug Rig
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$84



The Lake Union Swift is a 10-foot sailing dinghy and a variant of the popular Tenderly Dinghy.

While Tenderly is optimized for all-around utility as, well, a tender, the Lake Union Swift is more of a pure sailing machine. The two designs share a hull shape, but are otherwise distinctly different designs. The prototype was known as the "Tenderly XP." The Center for Wooden Boats in Seattle is currently building a fleet to use for sail training on Lake Union, and have given the design a much-better name: "Lake Union Swift."

Kits for the Lake Union Swift are available as a CLC "ProKit," a format suitable for builders who have assembled a few stitch-and-glue boats already. The ProKit builder should be comfortable reading boat plans and have experience working with epoxy and fiberglass. The Swift kit includes a detailed builders guide that comprises 38 pages of detailed step-by-step diagrams. The sailing component kit includes a custom 17-foot aluminum Dwyer mast, shipped full-length, along with specialized hardware including goosenecks, aluminum spreaders, and spreader brackets. To learn more about CLC ProKits here

Some background on this design:
Early on, it was noted that, quite aside from its admirable qualities as a yacht tender, the standard Tenderly is an unusually sprightly sailboat. Designer John C. Harris pondered whether a decked-in version with a taller rig and a bowsprit might make a fun daysailer, club-racer, or trainer.

One of the most obvious differences between Tenderly and the new design are the Lake Union Swift's structural bench seats, running most of the length of the boat. Without adding weight, the seats provide better ergonomics for sitting while under sail. The seats and forward deck enclose a vast watertight volume. This built-in flotation allows for rapid recovery from a capsizesomething more likely to happen with the sporty jib-headed sailplan. 

While adding slightly to the building complexity, the Lake Union Swift's pivoting centerboard will be appreciated by anyone launching from, or sailing through, shallow water.

John Harris's original idea was for the Lake Union Swift to be sold as a purist's sailboat, great fun for knocking about bays and lakes with one or two adults, or an adult and a couple of kids. The additional strings of the jib-headed rig make that option fun for experienced sailors, and give beginners (and kids) more to do. With their shapely lapstrake hulls and bowsprits, a fleet of these racing around the buoys would be strikingly pretty to watch, and a barrel of monkeys for the sailors.

The first prototype was built at the WoodenBoat School in 2017. After a few test cycles refining the sloop rig, it was observed that the Tenderly Dinghy's lug rig was plug-and-play in the Lake Union Swift. They share a common mast step, and no modification is required. Et voilà! Suddenly the Lake Union Swift becomes the elusive small sailboat design WITH comfortable bench seating! For those whose knees no longer answer for sitting on the floorboards, a Lake Union Swift with the lug rig's simple, single sail is a perfect fit.

Lake Union Swift Sailboat Kit

Since the Lake Union Swift and the Tenderly Dinghy are almost exactly the same weight, you get all of Tenderly's sparkling performance combined with the comfort and safety of bench seating. (If there's any doubt, check out the photos of the lug-rigged Lake Union Swift planing with a 185-pound crew aboard.)

Given watertight hatches in the tanks, the Lake Union Swift would work great as a small "beach-cruiser." A thwart amidships supports the centerboard trunk and is sited for comfortable rowing when the wind dies or if you need to work yourself clear of the shoreline.

Questions will arise about the interchangeability of sailing components between the Tenderly Dinghy and the Lake Union Swift. The two designs share the same hull shape, rudder, and mast step. Otherwise everything is pulled from separate parts bins, and there are limits to what features can be shared. In hopes of forestalling some of the Tenderly-versus-Lake-Union-Swift questions, here are a few quick FAQ's.

Frequently Asked Questions:

Gee, the Lake Union Swift has all these cool performance features. Why would I want to build the Tenderly instead? Tenderly is a delightful little sailboat in its own right and we've spent hours and hours sailing stock-standard Tenderly Dinghies. The important difference is that Tenderly has a more open, flexible interior layout compared to the Lake Union Swift. Tenderly is optimized to work well in many roles, including as a rowing boat, and the seating is arranged for comfortable boat-taxi service for up to three adults.  Tenderly can even take a small outboard engine. The Lake Union Swift's interior, by contrast, is arranged for a sailing crew of one or two adults, or an adult and a couple of kids. You can row the Lake Union Swift--easily, and a long way if you had to---but only from a single station, which would be a challenge if you had a passenger along.

Oooo! You said the magic word: ENGINE! Can I put an engine on the Lake Union Swift? Short answer: yes. Long answer: If you remove the rudder and sailing rig, you can clamp a small outboard to the Lake Union Swift's transom. What you CAN'T do (in either boat) is to mount an outboard off to one side on the transom, on standby as an auxiliary to the sailing rig or oars. The transom isn't big enough. To have the "outboard backup" option, you'll need to look to a boat the size and displacement of something like PocketShip.

I already have a Tenderly and its balanced-lug rig. Can I build a Lake Union Swift "base kit" and use the same sailing rig in both boats? Yes! Tenderly's unstayed mast drops right into the Lake Union Swift's mast step, and balance under sail is perfect.

I have a Tenderly. Can I put the Lake Union Swift's sloop rig in it? Welll...maybe. Aside from the mast step, you would need to integrate a lot of componentry peculiar to the Lake Union Swift's sloop rig, including the bowsprit and shrouds for the aluminum mast. We do not have any documentation or instructions to guide you through that particular mash-up.

I wish my Tenderly had a pivoting centerboard instead of a daggerboard. Can I order the Lake Union Swift's centerboard and swap it into my Tenderly? Short answer: No. Long answer: We appreciate the appeal of the Lake Union Swift's centerboard, but it just doesn't integrate well with Tenderly's interior. Your Tenderly would end up with the downsides of the Swift's sailing-oriented interior while giving up the advantages of Tenderly's ergonomic and flexible interior.

The Lake Union Swift's sloop rig has an aluminum mast. Is a wooden mast an option for the sloop rig? We tried. We built a couple of hollow wooden masts for the prototype Lake Union Swift. A mast for the sloop rig needs to be light, which makes the mast hard to build. In kit form the wooden masts would be more expensive than aluminum, with the additional disadvantage of being tricky to assemble. (The lug rig's much-shorter mast is a simple, solid stick. Classic folk technology that will never go out of style.)