Gulfstar 50 Kth Sailboat Review, Specs, and Listings

Design and Construction

The hull is a straightforward solid fiberglass laminate of mat and woven roving, stiffened not by molded liners but by full bulkheads and furniture components tabbed to the shell. A few hulls may instead be balsa-cored, but the deck is balsa-cored as standard, through-bolted to the hull and glassed over from below. The long fin keel carries lead chunks embedded in a concrete slurry, encapsulated rather than bolted, and the full-length rudder skeg is bolted in place. With 35,000 pounds of displacement, 10,500 pounds of ballast, and a 13-foot-8 beam over a 39-foot-8 waterline, the hull form is moderate and relatively narrow; the 30 percent ballast-displacement ratio means she benefits from early reefing to stay upright in a moderate breeze anchor. All tankage sits below the floorboards, which lowers the center of gravity, softens the motion, and frees storage space beneath berths and settees.

Rig and Handling

The sail plan is not especially large in either configuration — about 895 square feet as a sloop and 963 as a ketch — with wide mast spreaders and chainplates set nearly outboard, so sheeting angles stay open. In a seaway she is well mannered: the forefoot bites and the bilges are deep enough that she seldom slams in a chop, and she does not gripe to weather. Most owners report she won't sail well to windward unless the apparent wind angle is 45 degrees or greater, and she prefers moderate to heavy air, readily making 7 knots or better under working sail once the wind passes 12 knots, with light-air spinnakers or mizzen staysails needed below that anchor. The nominal hull speed is 9.3 knots.

Accommodations

The more popular layout grew out of the charter trade and carries three staterooms. Aft, the master suite has an en suite head and separate shower wrapped around an enormous U-shaped double berth; forward, a V-berth fills in to a double and shares a head with the saloon; to starboard midship, a third cabin holds two singles with its own small head. The L-shaped galley runs portside down the walk-through under the center cockpit, its twin sinks close enough to the centerline to drain on either tack. The saloon pairs a port dinette with a starboard settee and pilot berth. In the two-stateroom version, the midship cabin gives way to a wrap-around nav station and expanded engine space. Period reviews praised the superior teak joinery and generous volume, and the boat can sleep up to eight.

Known Issues

Hull blisters have appeared over the years, usually cosmetic but in some cases tied to saturated cavities around the ballast. The mainmast step is an iron plate in the bilge over the keel and is prone to corrosion; on ketch-rigged boats the mizzen step can crush the deck core beneath it. Leaking deck fixtures, hatches, and portlights are common, and in some boats the bronze stern tube around the rudderstock has separated from the laminate and needs rebonding. Loose tabs around bulkheads and sub-floor structures have also been reported and require re-tabbing.

Refits and Ownership

Most boats left the factory with a 62-horsepower Perkins diesel, reliable but slightly underpowered against a head sea; an 85-horsepower Perkins was later offered and drives her better. Several surviving boats have been repowered with turbocharged Yanmar diesels. The standard 100-gallon fuel capacity is modest for the size, and because the tank sits low the engine fuel pump works hard — a day tank higher in the boat with a transfer link is a worthwhile upgrade. Many were delivered with Onan generators that have proven troublesome and are best replaced. Owners who have addressed these points tend to be very satisfied.

The Verdict

The Gulfstar 50 Kth is a thoughtfully laid-out big cruiser whose simple, robust structure and versatile accommodations have aged well. She is a steady sea boat with a usable if not expansive sail plan, and the common defects are well understood and tractable. The low fuel capacity and temperamental generator are the main ownership caveats.

Pros