Sea-Lion 18 Information, Review, Specs

Built by Mobjack Manufacturing Corp., founded by the passionate designer Roger Moorman, the Sea-Lion 18 embodied the builder's commitment to modern construction techniques, particularly the use of fiberglass. While Mobjack Manufacturing Corp. was best known for its successful one-design Mobjack sloop, the Sea-Lion 18 demonstrated Moorman's willingness to explore new avenues in sailboat design and the burgeoning potential of multihulls for racing.

History and Design

Production of the Mobjack Sea-Lion 18 commenced in 1964, a period when the United States Yacht Racing Union (USYRU), now known as US Sailing, was actively involved in establishing unified racing rules, including those for new classes like the A-Class catamaran. The Sea-Lion 18 was specifically designed to adhere to these newly formulated USYRU A Class rules, which aimed to foster a development class for singlehanded racing catamarans. This design philosophy emphasized high performance through a lightweight platform and a powerful rig, allowing for continuous innovation within a defined set of parameters.

Mobjack Manufacturing Corp., under Roger Moorman's guidance, was known for its forward-thinking approach to boat building, embracing fiberglass as a primary material when many still favored traditional wood. This material choice provided durability and reduced maintenance, qualities beneficial for a competitive racing boat like the Sea-Lion 18. Although records indicate at least five Sea-Lion 18s were built, its production run was relatively short. The model was later replaced by the Hubbard-designed A-LION, which entered production in 1967 by different builders, American Fiberglass Corp. and Sailcraft Ltd., marking a transition in the A-Class landscape.

Sailing Performance and Handling

As an 18-foot catamaran, the Sea-Lion 18 was engineered for speed and agility, characteristic of the A-Class. With a length overall of 18.0 feet and a waterline length of 17.16 feet, combined with a narrow 7.5-foot beam, it presents a sleek profile designed to minimize wetted surface area. Its hull speed is calculated at approximately 5.55 knots, a testament to its efficient hull form. The boat features a twin centerboard keel type and a fractional sloop rig, typically employing a rotating spar to optimize sail shape and performance.

A-Class catamarans are renowned for being among the fastest single-handed small catamarans in the world, highly responsive, and capable of exceptional speeds with their powerful rigs. Sailors often describe these boats as sensitive to trim and balance, demanding active input from the helmsman to extract maximum performance. While specific anecdotal accounts for the Sea-Lion 18 are scarce, its adherence to the A-Class rules suggests a spirited performance, particularly in moderate to strong winds, where catamarans excel. The twin rudder configuration would have provided precise steering and control, crucial for competitive racing.

Accommodations and Layout

Given its design brief as a pure racing catamaran adhering to the A-Class rule, the Mobjack Sea-Lion 18 offers minimal, if any, interior accommodations. The A-Class is a single-handed racing class, prioritizing a lightweight and open deck layout for optimal performance and crew maneuverability rather than creature comforts.

Expect an open cockpit design with seating surfaces likely molded into the fiberglass deck for the skipper. Storage space would be limited to small compartments for essential safety gear and perhaps a few personal items. There would be no standing headroom or dedicated cabin, galley, or head facilities. The emphasis of such a design is entirely on maximizing speed and handling, with no provision for overnighting or cruising amenities. The hull material is fiberglass, which would have contributed to a clean, low-maintenance finish on deck, common for racing dinghies and small catamarans of its era.