J-Boats J/105 Sailboat Review, Specs, and Listings

Design and Construction

Most J/105s were built by Tillotson Pearson International, which pioneered the SCRIMP resin-infusion process for the hull, laying fiberglass and coring dry before infusion anchor. Vinylester resin runs throughout the boat, and the deck coring is balsa, with Baltek end-grain AL600 favored by the builder. The hull and deck are joined with Plexus, a chemical bond rated stronger than the laminate itself. Structurally, the hull is stiffened by fore-and-aft and transverse solid-glass hat sections molded at initial lay-up, while a matrix of robust floors supports the keel bolts and an aluminum I-beam maststep keeps the spar out of the bilge, through-bolted across two floors. Bulkheads carry six-inch tabbing through 360 degrees, and a serious bridgedeck adds both support and defense against green water in the cabin.

The narrow keel foil carries a torpedo bulb that drives ballast low and limits wetted surface anchor. With 3,400 pounds of lead in a 7,750-pound hull, the 44 percent ballast-displacement ratio lets the boat carry sail while others are reefed, and the deep fin with raked leading edge gives a limit of positive stability near 130 degrees. A 5-foot-6 shoal keel was offered for thin water, sacrificing some ultimate stability.

Rig and Handling

The fractional rig bends the mast for shape, and many boats carry a Hall Spars double-spreader stick with Navtec rod rigging, a Quick Vang, and a Sailtech hydraulic backstay. Harken roller furling is typical on the headstay. The mainsheet traveler sits forward of the helm, scooped into the T-shape cockpit, and a single pair of primary winches keeps control manageable from the seats. Strict class rules limit the inventory to main, jib, and asymmetrical chute—usually flown from a carbon sprit with under-deck launch and retraction, the spinnaker snuffed so one sailor can jibe.

Test sailors found an early hull off Miami held 12.5 to 13.5 knots in a 20-knot northeasterly with three-foot seas, touching 14.8, and clawed back upwind at 7.5 knots with sheets eased anchor. Owners report full main and jib tenable to roughly 22–25 knots before a reef goes in around 30. Standard tiller and hiking stick gave way on quite a few boats to an Edson wheel, and the straight-shaft drivetrain carries a Martec folder per class rule.

Accommodations

Below, the J/105 is honest about its priorities. Headroom runs just 5 feet 4 or 5 inches in the saloon except at the open companionway. Two settees port and starboard double as 6-1/2-foot berths, a 7-foot V-berth fills the bow with a hanging locker, and small quarterberths aft are optional. The split galley sits just aft of the main bulkhead: nav table to port, stainless sink and space for a one-burner Origo to starboard, with a 54-quart portable cooler under the ladder and a 5-gallon freshwater jug. A private head occupies the space just behind the bow berth, with a shower available as an option. Vinyl covers the overhead and hull sides; Sunbrella dresses the cushions.

Known Issues

Owners have reported trouble with the bulkhead supporting the chainplates, and on early boats the balsa deck core was left intact where the plates pass through, letting moisture reach structure; later hulls substituted solid glass anchor. The Bomar foredeck hatch drew aggravation—its frame welds crack flat on deck, and a bumper plus weld kit was later offered. The shallow bilge wets the floorboard ends when heeled; original plywood rotted, and later plastic-faced boards still delaminated. The rudder rides in aluminum bearings that corrode where they meet copper in antifouling paint; Jeff Johnstone cites a three-to-five year life, and some owners now fit Harken plastic. Soft engine mounts let the diesel dance, leaking dripless seals in some cases, and water has entered through the sprit tube in the forward cabin. Some emergency tillers were said not to fit at commissioning, or to sit hard to port when centered.

Refits and Ownership

The 10-year transferable hull warranty has long expired on used boats, but the structural bones age well. Rudder-bearing swaps to plastic, hatch bumper fitting, and sealed floorboard end grain are the common catch-up jobs. The class's tight three-sail rule keeps campaign costs contained, and the retractable sprit means no pole handling aloft.

The Verdict

The J/105 is a purist's speed machine: light, stiff, and refreshingly simple, built by a process that still reads as advanced. It asks its owner to accept thin headroom, minimal tankage, and a watch list of detail defects in exchange for a boat that planes in breeze and points without drama.

Pros