Design and Construction
The Ker 40 measures 12.2 meters overall, with a 4.15-meter beam and a 2.6-meter draft. It displaces just 4.8 tonnes but has the structural intent of a custom carbon project.
The hull form uses controlled volume. It carries more volume forward, particularly around a quarter of the way back from the bow. Aft, there are no chines, and the hull has enormous flare without resorting to hollows. This flare creates wide sidedecks around the cockpit and gives the boat a broad beam aft, gives the boat a broad beam aft, which IRC rewards heavily.
The waterline beam, however, is narrower than Tonnerre’s and is also narrower relative to the Ker 40’s maximum beam. The result is a narrow footprint through the water with little drag. At the transom, a lip replaces a rounded corner; the designer says this sharp corner provides better hydrodynamic properties.
Construction uses infused E-glass and epoxy around SP-provided M-Core PVC foam throughout the hull, deck, and interior structure. The finish is entirely painted, with no gelcoat. Flanged bulkheads remove the need for taping. Two beams of machined aerospace-grade alloy connect the keel-head loads to the fore-and-aft bulkheads and mast step.
The designer describes the Ker 40 as being built like a one-off but productionized. Engineering was carried out in the Ker office in the same manner as for a carbon boat, using judicious unidirectionals but working in glass. PVC foam was selected instead of Nomex because IRC is believed to penalize Nomex even more heavily than carbon. At this length, building the boat in carbon would save perhaps 150 kg at most.
Rig and Deck Layout
The Ker 40 has a fractional sloop rig. Its Hall Spars NZ mast and boom are built in high-modulus carbon, with twin sets of swept-back carbon spreaders and rod standing rigging. The sail-handling setup includes two masthead halyards and one fractional halyard for the kites, plus a single jib halyard. A bolt-on bowsprit carries the downwind inventory.
The jib foot can be lowered to deck level. Its sheet runs from a flying-ring fairlead on a lateral track, with 6:1 purchase and 24:1 up-and-down adjustment, directly to the primary winch. Mainsheet stoppers also lead to the winches, contributing to a clean deck layout.
Sailing and Handling
The fin was developed to provide a wider groove and make the boat more forgiving to sail. According to the designer, the Ker 40 has enough weight and stability to go “upwind like a train,” yet takes off sharply away from the wind.
Testers found the boat potent upwind despite its light displacement. It likes to be sailed with twist, with the main worked to maintain a constant heel angle. In the RORC Myth of Malham, the boat survived 45 knots and averaged 17 to 18 knots downwind for six hours.
The source expected sportsboat-like performance and described the boat as a blast, particularly downwind. Sailing World’s judges called it a work of boatbuilding art and excellent under sail.
Accommodation
Below deck, the Ker 40 is deliberately minimalist. A structural bench seat runs from the saloon aft to the transom, with pipecots above it. The galley is to port of the mast, while the chart table sits to starboard. Together, they provide the bare minimum required by the Special Regs. The plumbed-in heads is forward of the main bulkhead.
This is an interior designed to satisfy safety rules, not to accommodate guests in comfort.
Known Issues
The boat appeared bang on straight out of the box and required no major modifications. The principal owner-facing consideration is its minimalist accommodation and the demands of a lightly built racing platform, rather than any chronic failure mode.
Refits and Ownership
The production boat represents roughly a 50 percent saving over a one-off custom build. It allows owners to enter the grand-prix IRC game custom-fast but without custom cost.
The test boat, Catapult, was built for an experienced owner, primarily for offshore racing. Its custom features included a Harken pedestal, a generous navigation station, and pipe berths.
The recommended race crew is 11 to 12, while typical crews range from 10 to 12. Ownership is therefore centered on maintaining a race campaign rather than casual weekend sailing.
The Verdict
The Ker 40 is a semi-custom production racer that turns one-off engineering into a repeatable and competitive IRC weapon. It is aggressive and wicked-up for its size, yet forgiving enough to sail quickly across a wide groove. Its narrow waterline and flared topsides also provide a clever response to the handicap rule’s beam credit.
Pros
- Narrow waterline and flared hull reduce drag while earning IRC beam credit
- One-off-grade engineering in production glass at about half the cost of a custom build
- Forgiving, high-performance handling, with reported survival in 45 knots and downwind averages of 17 to 18 knots over six hours
Cons
- Minimalist interior meets only Special Reg requirements rather than providing cruising comfort
- Light-displacement racing platform calls for a race crew of 10 to 12 and campaign-level upkeep
