Hirondelle Mk I Sailboat Review, Specs, and Listings

Design and Construction

Hammond's hull geometry is deliberately symmetric, and the single-skin fiberglass shells carry no liners in the hulls or beneath the deck, which keeps the interior honest and easy to survey. The forward span between the hulls is mostly solid glass, with only the foremost foot or so spanned by a trampoline net. That solid forward deck adds weight, but it was a conscious concession to cruising utility: it houses several lockers sized for ground tackle, fenders, and lines. One owner reports the deck is balsa-cored, while the hull itself is single-skin glass; either way, all deck-hardware fasteners remain easily reached from inside. The overall construction is adequate but dated by modern standards.

Rig and Handling

The original Mk I carried a tall rig with a mast exceeding 30 feet and a working sail area of 250 square feet, opening to 330 with the widely used 150 percent genoa. A stock roller-furling boom simplified shorthanded sail handling, and the twin daggerboards gave the boat superior upwind ability. The rudders lift but do not kick up; if they hit bottom, the after ends of their trunks are built to break away rather than damage the hulls. A steering bar links the two rudders and tillers so the boat answers as a unit. Owners have found that she tacks through about 130 degrees, and that maintaining way when depowered mid-tack is best done with a gentle helm turn rather than a hard throw; sailing backward with the helm reversed is one reported trick to clear a stall. The manufacturer's own sailing notes warned that catamarans can capsize without self-righting and urged shortening sail early, and the boat accelerates better held straight through a gust than borne away. A Hirondelle once took the multihull class in the Around the Isle of Wight race, and writing in the source's editorial review the sailing performance was rated excellent in its day and still good for the size, particularly as a Mk I.

Accommodations

The bridge deck centers on a U-shaped dinette that seats four, and the table drops to form a large berth, albeit interrupted by the mast compression post that also carries the clamp holding the table up. Fixed backrests line the outboard side. Sleeping spreads across the hulls: two single quarter berths aft, a single forward in the starboard hull, and the convertible dinette, giving the standard layout four or five berths. The head with a portable toilet sits forward in the port hull, while most Mk Is were fitted with sea toilets and a small stowaway basin. A small galley with a two-burner stove lies abaft the dinette on the bridge deck, and a molded sink in the starboard hull serves it. Storage is a network of doorless cubbies.

Known Issues

The daggerboard-and-lifting-rudder layout demands attention to the auxiliary. A long-shaft outboard projects below hull level and, if left down, risks running aground. The builder's sailing instructions are blunt that these catamarans can remain capsized and will not return to level, so early reefing is the prescribed habit rather than a suggestion.

Refits and Ownership

A high percentage of Mk I hulls were home completed, so individual boats vary in finish and systems. The later Mk II carried a shorter mast, and late-1970s Mk IIIs moved to fixed keels and upgraded interiors; the subsequent Hirondelle Family held the length but added two feet of beam, pushed the cabin forward, and offered the Aero Rig with headsail and mainsail on one rotating boom. For the Mk I itself, an outboard to 25 horsepower mounts in a well aft in the cockpit, with fuel tanks stowed under the port and starboard helm seats.

The Verdict

The Hirondelle Mk I is a thoughtfully laid-out pocket catamaran that punches above its 23 feet under sail, with a genuine cruising interior and a builder's candor about multihull limits. Its dated construction and home-build variability ask the buyer to inspect carefully, but the fundamental design remains a quick, roomy weekender.

Pros