Moody S31 FK Information, Review, Specs

The S31 was produced in two primary configurations: the Fin Keel (FK) and the Twin Keel (TK). While the twin-keel version was popular in the drying harbors of the UK’s East Coast and Brittany, the Fin Keel variant discussed here is the preferred choice for sailors prioritizing windward performance and stability in heavy weather. It shares its hull design with no direct siblings in a different size class, but it heavily influenced the design language of the larger Moody 336, which shared the same design ethos of a high-volume, aft-cockpit cruiser.

Sailing Performance & Handling

The Moody S31 FK is a stiff and capable performer, benefitting significantly from its Bill Dixon-designed hull that carries its beam well aft. Unlike the masthead rigs of earlier Moodys, the S31 utilizes a 7/8 fractional rig, which allows for greater control over mainsail shape and makes the boat easier to handle for short-handed crews. The fin keel version draws approximately 1.68 meters (5’ 6”), providing a lower center of gravity that translates to less heel and better tracking when beating into a chop.

According to technical evaluations by the Moody Owners Association, the S31 is noted for its balanced helm. The rudder is semi-balanced and spade-mounted, providing more "feel" than the skeg-hung rudders of older models. In light airs, the S31 is surprisingly responsive for a cruising yacht of its displacement, though it truly excels in a Breeze. With a ballast ratio of roughly 30%, it remains upright and secure when smaller 30-footers are beginning to reef. Owners often report that the boat feels "bigger" than its 31 feet, handling coastal passages with a level of sea-kindliness typically reserved for 35-foot vessels.

Interior Comfort & Variations

The interior of the S31 was a revelation at the time of its launch, utilizing the increased beam to create a layout that feels remarkably spacious. The joinery is typically finished in American Cherry or traditional Teak, providing a warm, high-quality atmosphere that avoids the "plastic" feel of some contemporary mass-produced boats. The headroom is a standout feature, reaching approximately 6' 2" in the main saloon, which is exceptional for a yacht of this length.

The layout features a dedicated forward V-berth, a central saloon with facing settees and a folding leaf table, and a large L-shaped galley to starboard. The "S" designation truly shines in the aft section; by moving the cockpit slightly forward and utilizing a stern-cockpit design, Dixon was able to fit a massive transverse double cabin under the cockpit sole. This aft cabin is often cited as the boat's best feature, offering a full-sized double berth and a hanging locker. To port, a proper forward-facing navigation station and a surprisingly large heads compartment with a wet locker complete the accommodation. The S31 FK did not see major interior variations during its production run, as the layout was considered nearly optimized for the 30-32 foot bracket.

Known Issues & Buyer’s Checklist

Prospective buyers should focus their inspections on a few specific areas common to the Marine Projects builds of this era. While the hulls are solidly constructed GRP, the balsa-cored decks should be checked for "soft spots" or delamination, particularly around stanchion bases and the windlass.

The S31 was originally fitted with the Volvo Penta MD2020 engine. While reliable, the saildrive diaphragm (the rubber seal between the drive and the hull) has a recommended replacement interval of seven years; if there is no record of this being done, it should be a priority. Furthermore, the heat exchangers on the MD2020 are prone to internal corrosion if the sacrificial anodes were neglected.

Inside the cabin, "Moody sag"—the tendency for the foam-backed vinyl headlining to unstick and droop over time—is a common cosmetic issue. Replacing the headlining is a labor-intensive task but a frequent project for DIY owners. Additionally, the rudder bearings should be checked for play; because it is a spade rudder, any significant wobble can lead to vibration under power or a less precise feel at the helm.

Community & Resources

The S31 benefits from one of the most active and technically proficient owner groups in the maritime world. The Moody Owners Association maintains an exhaustive archive of original brochures, wiring diagrams, and DIY repair guides specifically for the S31. This community is an essential resource for sourcing parts that are no longer in production, such as specific window seals or rudder components.

The Verdict

The Moody S31 FK is a quintessential "pocket cruiser" that offers the build quality and offshore confidence of a much larger yacht. It is an ideal vessel for a couple or a small family looking to transition from day-sailing to coastal or cross-channel cruising. While it may command a higher price on the used market than its French-built contemporaries, the investment is rewarded with superior resale value and a more refined interior.

Pros:

• Exceptional interior volume and headroom for a 31-foot boat.
• High-quality joinery and robust Marine Projects construction.
• Predictable and stiff handling thanks to the fin keel and Dixon hull.
• The aft cabin is among the best in its class.

Cons:

• Headlinings are prone to sagging and require expensive or time-consuming repair.
• The Volvo Penta saildrive diaphragm requires regular, costly maintenance.
• The fractional rig requires more active backstay tuning than simpler masthead rigs to get the best performance.