Design and Construction
Peterson's approach was to build on fiberglass with a Divinycell cross-linked PVC foam core deck, a material choice that kept structural weight out of the topsides while providing genuine stiffness and insulation. The oiled teak trim was a concession to the aesthetic tastes of the era, but the underlying structure reflected contemporary racing practice. A fin keel carrying 7,700 lb of lead ballast gives the 17,000-lb displacement hull a ballast ratio that prioritizes initial stiffness and upwind drive rather than ultimate range of positive stability — a bias that suits the boat's racer-cruiser mandate. An optional shoal-draft keel at 5.16 ft was available for buyers sailing coastal or estuarine waters, though those hulls typically received a shortened rig to compensate for the reduced righting moment. The spade rudder, mounted inboard rather than hung from a transom skeg, reflects Peterson's racing instincts: it loads up predictably and responds quickly, but places a premium on keeping the bearing surfaces and shaft seal in good condition as the boat ages.
Rig and Sailing Performance
The masthead sloop rig on aluminum spars carries a working sail area of roughly 734 square feet across a 296-square-foot mainsail and a 437-square-foot genoa. The 53-foot foretriangle height gives the boat excellent reaching and running power when paired with a 150-percent genoa or the large asymmetrical spinnaker for which published dimensions run to over a thousand square feet. A PHRF handicap of approximately 82 places the Islander 40 in genuinely competitive company for a cruising-weight 40-footer — quick enough to embarrass production cruisers of similar vintage, but not so radical that the crew needs racing instincts to keep the boat safe. The mainsheet traveler sits on the coach house roof, a practical placement that keeps the cockpit clear while allowing precise trim adjustments. Sheets and halyards lead aft to the cockpit, reducing the need for crew forward under sail, and the factory-standard topping lift, internally mounted outhaul, and reefing gear reflect a boat configured for short-handed offshore work from the beginning.
Accommodations and Interior Layout
Six-berth accommodation is organized across three distinct sleeping spaces: a private V-berth forward, an aft quarter berth tucked under the cockpit, and two settee berths in the main cabin joined by a port-side pilot berth above. This arrangement gives owners genuine flexibility — couples can claim the aft cabin as a sea berth and leave the forward cabin for guests, or the whole crew can bunk out across all three zones on a passage. The galley at the foot of the companionway steps is practical rather than palatial: a three-burner propane stove with oven and both pressurized and foot-pump fresh-water systems serve a 60-gallon tankage. The navigation station opposite the galley on the starboard side enjoys a natural sight line toward the companionway. The head includes a shower with a teak grating over the sump, a detail that remains a genuine amenity rather than a token installation. Six opening ports plus hatches over the bow cabin and main cabin give the interior enough cross-ventilation to be livable in warm anchorages.
Known Issues and Age-Related Considerations
Because production spanned a relatively short window and hulls are now decades old, buyers should scrutinize the foam-core deck construction carefully. Divinycell was an advanced core material for 1979, but the PVC foam core deck is susceptible to water ingress wherever fasteners have been through-bolted over the years, particularly at the mast base, chainplates, and stanchion bases. Delamination in older hulls is not universal, but it is common enough to warrant systematic percussion sounding before any purchase. The Volkswagen Pathfinder diesel engine — a 42-hp unit fitted for docking and maneuvering — is long out of manufacturer support, so buyers should expect that running examples have already been repowered or will require repowering. The spade rudder arrangement, while fast, demands that bearing housings and shaft seals receive inspection with regularity; a rudder that develops play below the waterline on a fin-keel boat with no skeg protection is a potential emergency.
Refit Priorities
The limited production run means that owners are largely on their own for sourcing parts, which concentrates refit effort around the drivetrain and running rigging. A repower with a modern 35-to-50-hp diesel — Yanmar, Volvo, or Beta units are commonly substituted — transforms reliability and fuel economy simultaneously. Standing rigging on any boat of this vintage should be replaced as a baseline; the aluminum spars themselves tend to remain structurally sound, though corrosion at the masthead sheave boxes is worth addressing. The internally mounted outhaul and reefing system should be inspected for sheave wear and internal corrosion. Teak deck or trim replacement is often discretionary but can substantially affect resale appeal. Owners who add a quality autopilot and a modern chartplotter find that the cockpit layout — already rationalized to bring most controls aft — integrates the electronics naturally.
The Verdict
The Islander 40 is a clean-pedigreed, low-production offshore capable racer-cruiser from one of the sport's more respected designers. Its hull form is honest: not a sluggish cruiser with a racing stripe, and not a stripped-out racer with a token pilot berth. The boat sails properly on both legs of that bargain. The Divinycell-cored deck construction was ahead of its time, but those same decks now demand careful inspection in aging hulls. The Volkswagen diesel is an expected casualty of the years, and buyers should budget for a repower as a practical matter. For anyone willing to do that homework, the Islander 40 rewards with genuine upwind performance, a comfortable offshore interior, and the quiet satisfaction of sailing something rare.
Pros
- Doug Peterson hull form delivers genuine PHRF-competitive performance in a cruising-weight package
- Divinycell foam-core deck reduces topside weight while stiffening the structure
- Six-berth layout with three distinct sleeping zones including a private aft cabin
- Masthead rig sized generously for reaching and downwind passages
- Cockpit-led sheets and halyards rationalize short-handed sailing
- Spade rudder provides quick, responsive steering
Cons
- Foam-core deck vulnerable to delamination at through-fasteners on older hulls
- Volkswagen Pathfinder diesel is out of support; repower is a near-certainty
- Small production run limits parts availability and class community support
- Spade rudder with no skeg protection requires diligent bearing maintenance
- Shoal-draft option reduces performance and requires a shorter rig
- Detailed inspection work demanded by age of all surviving hulls
