Design and Construction
The Endeavour 51 was built by the American yard Endeavour Yacht Corporation in fiberglass, with both hull and deck executed as a sandwich construction using balsa core, a method the period review credited with improving the indoor climate. The core material in that sandwich is balsa, and because balsa wood is used as sandwich core material special care must be taken in relation to work that require penetration of the sandwich construction in order to prevent water to get in contact with the balsa wood. Structurally, the design employed a winged rudder as well as a winged keel, though some E51s only have the winged keel. The shoal-draft winged-keel option measured 5 feet 0 inches at introduction and grew to 5 feet 8 inches from 1989, while the standard draft was 7 feet 6 inches. With a displacement of 37,500 pounds and 17,300 pounds of ballast, the boat carries a capsize screening value of 1.79, a figure that by the relevant formula alone would admit her to ocean racing, and a motion comfort rating of 34.75 that suggests a steady, forgiving motion in a seaway.
Rig and Handling
The Endeavour 51 is built with a masthead rig, and the sail plan is generous: the manufacturer lists 1,238 square feet at 100 percent with a 523 square foot mainsail and a 714 square foot foretriangle, while the editorial review records 100.2 square meters (1,078.3 square feet) for mainsail plus jib. The SA/D ratio sits at 17.68 by the builder's numbers and 15.4 with the ISO 8666 reference sail, rising to 18.5 with a 135 percent genoa. Her D/L ratio of 222 places her among what one source terms "moderate racers," and the theoretical displacement-hull speed is 8.71 knots. Keel choice drives handling envelope: with the wing keel the boat can enter most marinas as the draft is just about 1.73 to 1.83 meter (5.68 to 5.98 ft) dependent on the load, whereas the fin-keel variant can only enter major marinas as the draft is about 2.29 to 2.39 meter (7.51 to 7.81 ft) dependent on the load. Rigging details are thoroughly documented, from a 39.8 meter mainsail halyard to a 38.8 meter mainsheet, all sized for a large offshore cruiser.
Accommodations
Two interior arrangements define the Endeavour 51. The charter layout had two aft cabins, each with their own heads, while the private owners layout had a single aft master stateroom and head. Forward was a traditional v-berth followed by 2 quarter berths—one to port and the other to starboard, yielding a boat equipped with 3/4 cabins and 6/8 berths depending on configuration. Headroom is 7 feet 0 inches, described in review as above average, and a galley serves the main saloon. The water capacity is given as 300 gallons by the manufacturer and 399 US gallons by the editorial review (sources differ), and fuel capacity as 100 gallons diesel versus 159 US gallons (sources differ), framing a boat intended for extended independent cruising rather than weekend coast-hopping.
Known Issues
The principal documented vulnerability flows from the balsa-cored sandwich construction: any penetration of the hull or deck sandwich risks water reaching the balsa and causing core decay, so through-bolted additions, deck hardware resealing, and prior owner modifications demand close inspection. No other structural or systems defects appear in the source material, and the records are silent on osmotic blistering, rigging fatigue, or tank failure.
Refits and Ownership
Owners working on an Endeavour 51 should note the Perkins 4-236 (85hp) auxiliary with 1.9 to 1 reduction gear and 62 amp alternator as the documented standard power plant, though the editorial review notes the boat may be equipped with an inboard Yanmar diesel engine. The immersion rate of about 394 kg/cm (2208 lbs/inch) and a wetted surface near 61 square meters (656 square feet) are useful figures when sizing ground tackle, estimating antifouling, or predicting load-driven draft change. Given the balsa core, any refit penetrating the sandwich must be executed with moisture exclusion as the priority.
The Verdict
The Endeavour 51 is a purpose-built mid-1980s center-cockpit cruiser of serious displacement and volume, designed by Johan Valentijn with a genuinely oceanic stability profile and a flexible two-layout interior. She rewards an owner who respects the balsa-core penetration risk and who values steady motion and marina access via the shoal wing keel over outright sprint speed.
Pros
- Substantial 37,500 lb displacement with 17,300 lb ballast and 1.79 capsize screening value for offshore-capable stability
- Shoal wing-keel option (5'0" to 5'8") permits most-marina access dependent on load
- Two distinct interior layouts (charter twin-aft or owner single-aft master) with 6/8 berths
- Documented masthead rig with full halyard and sheet specifications for offshore provisioning
Cons
- Balsa-cored sandwich hull and deck require special care against penetration-induced water ingress
- Fin-keel draft (~7.5–7.8 ft) restricts the boat to major marinas only
- Source discrepancy on water and fuel capacity complicates systems planning
