The last sailboat I owned had about 40 square meters of sail area which is just right for double handed sailing. The K-42 is designed around a 42 square meter sail plan that meets the requirements of the 40 square meter class under the Square Meter Rule. Hull dimensions also are within the 40 square meter limits, except for the seperate spade rudder. Additionally, the K-42 was designed with an 8 foot cockpit and watertight subdivision. The watertight subdivision consists of two watertight bulkheads and a forward foam filled buoyancy compartment. The K-42 will remain afloat and meet MCA damage stability requirements when flooded.

Interior volume was a relatively low design priority behind ease of sail handling and adhering to the traditional square meter style. Consequently, the K-42 has minimal accommodations with only 4'-11" headroom. Sail handling is simplified by using as few control lines as possible. There is no mainsheet traveler, no backstay adjuster, and no running backstays. Headstay tension is achieved with swept back spreaders. The rig incorporates a second set of spreaders at the top of the fore triangle for transverse support of the mast above the hounds.

Auxiliary power is an electric motor instead of the usual diesel engine. It has been my experience that the engine installation is and afterthought in most sailboat designs, and the designer rarely considers the details of the engine installation, leaving that sort of thing up to the builder. I decided to provide a detailed machinery arrangement with the K-42 plans and started working out the details for a diesel engine installation considering the locations of the fuel tank, muffler, exhaust line, ventilation, cooling water intake, and sound/thermal insulation. It all seemed way too complex for auxiliary power that would be hardly ever be used. So I went with an electric motor for auxiliary power instead. No diesel fuel, no smelly exhaust, no noise, no oil leaks.

Hull construction for the K-42 is single skin fiberglass with transverse frames and bulkhead stiffening. I prefer a single skin hull over a cored hull for greater impact resistance and no chance of core shear failure or water damage to the core. The deck is closed cell foam core with fiberglass skins. Scantlings are to ISO 12215-5, "Design Pressures for Monohulls, Design Stresses, Scantlings Determination".