Hull and Construction
The hand-laid solid fiberglass hull avoids the complexities of cored topsides, while the balsa-cored deck is injection-molded to reduce weight and increase stiffness — and, according to Jeanneau, reduce emissions during manufacture. Below the waterline, the topsides carry a blister-resistant barrier coat applied over ISO gelcoat. Structural rigidity comes from an interior counter-molded grid glued and laminated to the hull, with deliberate cutouts in the grid to preserve access to high-load areas. The keel is a cast-iron bulb fin, available in deep (7ft 5in) or shoal (5ft 8in) configurations, and the rudder is a spade. Displacement lands at 30,644 pounds, and the ballast-to-displacement ratio of 30.94 places the 509 firmly in cruiser rather than ocean-racer territory — adequate for her intended mission but not a figure that inspires adventurism in serious offshore conditions.
Rig and Sail Handling
Briand gave the 509 a high-aspect fractional sloop rig on an aluminum twin-spreader mast with discontinuous wire rigging, and Jeanneau built notable flexibility into the headsail arrangement. Buyers could specify a large overlapping genoa on conventional side-deck tracks, a smaller overlapping jib, or a purely self-tacking jib on an athwartships track — or order all three sets of hardware and keep every option open. The SA/displacement ratio of 20.11 sits at the upper edge of the moderate-performance band, and designer polars predict 7 knots in 14 knots of true wind at 40 degrees apparent, with similar figures across a broad range of angles. In practice, the Cruising World test recorded 7.5 knots reefed down in 15 knots of wind, suggesting the hull is genuinely efficient rather than merely optimistic. The mainsheet runs double-ended to the primary winches, which keeps control convenient from either helm station but means jibsheets and the mainsheet share the same primary winches — a compromise that demands sharp line discipline during gybes in a breeze. All halyards and mast controls route to a pair of coachroof winches either side of the companionway.
On Deck
Twin helm stations dominate the cockpit, each built around curved steering pedestals that double as seatbacks for the cockpit benches, a detail that eliminates the awkward filler cushions common on many twin-wheel designs. A motorized fold-down transom opens the stern for swimming or dinghy handling, and the wide transom supports a single centerline backstay rather than dual-leg arrangements — a choice that simplifies the rig and avoids the crowding that makes helming from the outboard position uncomfortable on other boats. Forward, there is a dedicated sail locker and a large anchor well; the anchor roller is set outboard of the bow with a welded tack attachment for flying asymmetric spinnakers and large reaching sails. Storage under the cockpit bench seats is generous, though the coamings behind those seats are noted as somewhat low for solid back support during long watches at sea.
Accommodations
The 509 was offered in three-, four-, and five-cabin configurations, a range that explains its appeal to both family owners and charter operators. The flagship three-cabin layout gives each aft cabin a full-size double berth, with the forward space configured as a large master suite incorporating a head with a separate shower. The galley, positioned aft to starboard, is particularly well-executed: nine separate stowage compartments within easy reach of the cook, sinks placed close to the centerline, and a "tea galley" forward of the main prep area with a front-opening drinks fridge and a dedicated cutlery drawer oriented toward the saloon. A large nav station sits opposite, with a desk sized for a full paper chart and a deep top-loading stowage locker alongside. The interior woodwork uses sustainable teak-colored Alpi, a choice that maintains the traditional look without drawing on old-growth timber stocks. Headroom runs 6ft 6in throughout, and berth dimensions are 6ft 9in by 5ft in the aft cabins, 6ft 8in by 5ft 4in forward. Water capacity is a generous 163 gallons, meaningful for extended offshore passages.
Under Power and Known Shortcomings
The 75hp Yanmar diesel driving a saildrive proved capable under test, delivering 7.2 knots at a moderate 2,000 rpm and 9.1 knots at maximum revs, numbers that give the 509 honest passage-making ability in calms. A joystick-controlled 360 Docking system combining a bow thruster and a rotating saildrive was available as an option, simplifying marina handling on a hull of this size. The folding propeller, however, requires a pause after engaging reverse for the blades to reorient — stopping distance is longer than expected as a result. The more substantive concern voiced by Cruising World's test is the in-mast furling main option: the roachless sail profile is a measurable performance penalty on a hull otherwise capable of efficient sailing, and the trade-off between ease of handling and sail power is a genuine one that buyers should weigh before specifying it. The capsize screening formula of 1.97 clears the commonly cited 2.0 threshold for offshore passage-making, if narrowly, and the comfort ratio of 26.38 places the 509 at the lighter end of the coastal-cruiser band — not a figure that should deter bluewater aspirations, but one worth understanding.
Refits and Upgrades
The 509 was a popular charter boat in fleets from the Mediterranean to the Caribbean, which means many hulls have accumulated hours and hard use. Buyers should inspect the saildrive seal carefully — a standard precaution on any Jeanneau from this era. The sail locker forward lacks shelving for organizing smaller items, an acknowledged shortcoming that is straightforward to retrofit with a few custom boards. The shared-winch arrangement for jibsheets and mainsheet is the one deck-layout compromise that frustrates experienced sailors most; adding secondary winches is not structurally possible without significant work, so buyers who want dedicated sheet handling should plan their crewing arrangements accordingly. The optional 360 Docking system adds complexity to the drive train; prospective owners buying a used example so equipped should budget for a thorough inspection of the bow thruster tube and the rotating saildrive mechanism.
The Verdict
The Jeanneau Sun Odyssey 509 is a well-engineered, Briand-designed fifty-footer that delivers genuine sailing performance alongside the kind of interior volume usually associated with charter boats. She makes 7 knots or better on virtually every point of sail in moderate breeze, handles beautifully under power with the right propeller specification, and offers a galley and nav station that betray real thought about life at sea. The shared primary winches and the performance penalty of the furling main are real compromises rather than marketing oversights, and buyers should go in with clear eyes about the comfort ratio and capsize numbers if bluewater passages are the plan.
Pros
- Briand hull is genuinely fast and efficiently driven for her size
- Exceptional interior volume with thoughtful galley and nav station
- Flexible headsail options accommodate a wide range of sailing styles
- Fold-down transom, twin helms, and 360 Docking option simplify passage and marina sailing
- Shoal-draft option opens cruising grounds unavailable to deeper boats
Cons
- Jibsheets and mainsheet share primary winches — no room for secondary winches
- In-mast furling main (popular option) carries a meaningful sail-area and performance penalty
- Comfort ratio of 26.38 places motion comfort at the lighter end of the coastal-cruiser range
- Cast-iron ballast requires monitoring for rust weep in older hulls
- Saildrive folding-prop arrangement lengthens stopping distance under power
