Hirondelle Mk III Information, Review, Specs

Sailing Performance & Handling

The Hirondelle Mk III is a lightweight performer with a Sail Area to Displacement (SA/Disp) ratio of approximately 23, placing it well into the "high performance" category for cruising vessels. According to editorial analysis by Good Old Boat, its light displacement of roughly 2,700 lbs allows it to excel in light-to-moderate air, outpointing many monohulls of similar length.

Unlike the Mk I and Mk II, which utilized twin daggerboards and lifting rudders, the Mk III’s fixed keels provide a deeper static draft of 2.5 feet. This trade-off prevents the "ditch-crawling" versatility of earlier models but gains significant tracking stability and structural rigidity. Owners often note that the Mk III feels more planted in a chop, with less of the "hobby-horsing" motion common in ultra-light multihulls. Handling is reported as forgiving, though like most catamarans of this era, tacking requires positive helm to prevent getting caught in stays if momentum is lost.

Interior Comfort & Variations

The most significant impact of the Mk III’s design change was the reclamation of interior volume. By removing the daggerboard trunks that bisected the hulls in earlier versions, the Hirondelle Association notes that the Mk III gained enough lateral space for an improved galley layout and a full-sized hinged chart table. The interior typically features a central bridge-deck saloon with a dinette that converts into a queen-sized double berth.

The hull configurations are symmetrical, housing two generous single quarter berths in the aft sections. The port hull forward usually contains the heads, while the starboard side is dedicated to storage or a small forward berth. The transition between the Mk III and its sibling, the "Hirondelle Family," is notable; the Family version extended the beam from 10 feet to 12 feet, further increasing the bridge-deck volume and allowing for a larger galley and a dedicated shower in the heads.

Known Issues & Buyer’s Checklist

Prospective buyers should focus on the following high-signal technical areas:

• Mast Compression: The mast is stepped on the bridge deck. It is critical to inspect the compression post and the bridge deck itself for any signs of sagging or stress cracking, particularly if the rig has been over-tensioned.
• Outboard Well Integrity: The auxiliary power is centrally located in a cockpit well. Check for galvanic corrosion on the engine if it has been left in the water, and inspect the well's fiberglass bonds for delamination caused by engine vibration.
• Keel-to-Hull Bonds: Since the Mk III features fixed keels, ensure there is no evidence of structural "smile" or weeping at the join, which could indicate a hard grounding that compromised the hull-to-keel joint.
• Rudder Bushings: The fixed spade rudders on the Mk III are prone to wear in the bushings. Any significant play at the helm during a survey usually points to the need for a bearing replacement.

Community & Resources

The most authoritative technical resource is the Hirondelle Association, which maintains an extensive archive of original brochures, rigging diagrams, and historical data for all marks. The community is particularly active in the UK and Western Europe, where most of the 300+ hulls were originally sold.

The Verdict

The Hirondelle Mk III remains a premier choice for sailors seeking a fast, stable, and trailer-capable multihull that punches well above its weight class in terms of accommodation.

Pros:

• Exceptional light-air performance due to high SA/D ratio.
• Level sailing provides a safe platform for families or aging sailors.
• Low maintenance fixed keels compared to daggerboard versions.
• Strong owner community and technical support.

Cons:

• Limited standing headroom (typical for 23-foot catamarans).
• Increased draft compared to Mk I/II limits extreme shallow-water access.
• Fixed rudders make the boat more vulnerable in accidental groundings.