Catamaran, twin centreboards · Frac. Sloop (Rotating Spar) · First built 1964
A 1964 USYRU A-Class racer with a rotating spar and twin centerboards, built to push the limits of early catamaran design
Designed by Hubbard, David & Jerry Hubbard, built by Mobjack Manufacturing Corp.
LOA
Beam
Draft (max)
Displacement
Hull type
Catamaran Twin Cbrd.
Is it for you?
Character
Where this design lands on the numbers a shopper trusts — read straight from her own ratios.
TrailerableBeam 2.29 m — inside the 2.55 m no-permit tow width across most of Europe, and the 2.59 m US and Canadian limit. About 136 kg of hull, so roughly 750 kg on a trailer: check that against your own towing rating.Ramp-launchableAbout 136 kg of hull, with a keel that raises or a draft shallow enough to float off a trailer — she can go back on the trailer at the ramp, not only into the water.Shoal draftDraws 0.13 m, board up where she has one — creeks, sandbars and thin anchorages most keels have to stay out of.
LightHeavy
27 — light for her waterline, so she is easily driven and quick to accelerate.
Displacement / length 27
EasygoingPowered-up
49.0 — a lot of sail for her weight; powered-up and eager, a real performer.
Sail area / displacement 49.0
Narrower than ~83% of boats her size on file
Compared with 147 boats of the same type within a quarter of her length.
The record
Full specifications
The complete reference set — tap any figure to switch between metric and imperial.
Dimensions
Weights
Rig & sail area
Rig
Frac. Sloop (Rotating Spar)
Ratios
SA / displacement
49.0
Displacement / length
26.5
Hull
Hull type
Catamaran Twin Cbrd.
Construction
Fiberglass
Production
Years built
First built 1964
Designer
Hubbard, David, Jerry Hubbard
Builder
Mobjack Manufacturing Corp
Boats like this, on the water
Nobody has filmed this one — but these are close.
Comparable boats the fleet has on camera: same type, within a quarter of her length. Open the boat, or watch the video — a timestamp means she only appears in passing.
Supercat 154.65 mSame hull family0.8 m shorterA high-performance beach catamaran with a rotating spar and an exceptional sail-area-to-displacement ratio
Hobie 165.05 mSame hull family0.4 m shorterThe most popular sailing catamaran ever built, featuring a rotating spar and boardless hull for high-speed beach sailing
Hobie Tiger 185.51 mSame hull familyNear-identical lengthDesigned to the Formula 18 rule, this 5.5-meter catamaran features twin daggerboards and a high power-to-weight ratio
Hobie FX One5.18 mSame hull family0.3 m shorterA 5.18-meter single-handed catamaran featuring a rotating fractional rig and an exceptional 56.56 sail area-to-displacement ratio
Hobie 21 SE6.48 mSame hull family1.0 m longerA high-performance catamaran with a rotating spar, originally developed as a one-design for professional racing
Astus Boats 226.65 mSame hull family1.2 m longerA Stephan Vallet-designed trimaran with a high sail-area-to-displacement ratio built for rapid, stable coastal cruising
