Design and Construction
The hull is solid hand-laid glass-reinforced plastic, while the deck uses a balsa core to keep stiffness without piling on weight deck utilises a balsa core to maintain stiffness. Internal structure comes from a glassed-in grid — Jeanneau's "matrix" — that distributes both rig and keel loads through the hull. What sets the 51 apart visually and structurally is the long sweep of coachroof windows: large acrylic panels chemically bonded to a recessed flange in the GRP instead of framed in heavy aluminium. A defining feature is the exceptionally wide beam of 16 feet, carried well aft, which allowed the builder to fit twin steering wheels — a genuinely revolutionary choice for a production boat of this size at the time. Rig loads are managed by a sophisticated internal tie-rod system: stainless deck plates connect to high-tensile rods running down to heavy brackets bolted straight to the main structural bulkheads.
Rig and Handling
Delivered primarily as a powerful masthead sloop, the 51 carries an optional inner forestay for offshore work. The sail plan is substantial — a 513-square-foot main with a 54-foot-10-inch luff and an 18-foot-8-inch foot, paired with a 555-square-foot 100 percent foretriangle on a 62-foot hoist and 17-foot-11-inch base, for a total of 1,068 square feet. Her sail-area-to-displacement ratio of 17.3 marks her as a moderate-performance cruiser, not a featherweight. Under power, an 80-horsepower Perkins or Yanmar drives her at a comfortable 7.5 to 8 knots at 2,200 rpm. Steering is via a spade rudder, and the wide stern demands she be sailed relatively flat to keep optimal control — a characteristic of the beamy aft sections rather than a flaw.
Accommodations
Below, the boat splits into two common variations: a four-cabin layout favoured by charter fleets and a more palatial three-cabin owner's version. The cockpit is expansive, built around a fixed central table that serves as the hub for deck dining. To port, a longitudinal galley offers vast counter space and excellent refrigeration capacity, a layout that has made the model a favourite among liveaboards. Tankage underpins that liveaboard appeal, with water capacity exceeding 200 gallons.
The Verdict
The Sun Odyssey 51 is a thoughtfully engineered late-1980s cruiser that balanced volume and ocean capability. The Farr-J&J collaboration produced a beamy, stiff hull with genuine offshore credentials, and the structural details — internal tie-rods to bulkheads, a glassed-in matrix, bonded acrylic windows — show a builder pushing production-yacht sophistication forward. She is not a sparkling light-air performer, but her comfort ratio of 26.9 and Category A rating make her a dependable passage-maker.
Pros
- Category A ocean classification with a 32.1% ballast ratio and 2.04 capsize screen
- Twin wheels and wide-beam-aft layout that was ahead of its production era
- Internal tie-rod rig structure bolted to main bulkheads for load management
- Expansive cockpit and longitudinal galley suited to liveaboard cruising
Cons
- Spade rudder and wide stern require sailing her flat for best steering
- Balsa-cored deck demands careful moisture inspection over time
