The Islander 36 is a well-regarded 1970s cruiser-racer with a solid uncored hull, but its narrow shroud base means upwind loads can approach the boat's own displacement, and almost every one of its signature problems is hidden. Use this list to know what a survey of a forty-plus-year-old boat must not miss.
The deck is cored (plywood per the primary review, balsa per some owners) and water enters through the toe-rail bolts, chainplate slots, mast step, and stanchion bases, and core rot near the mast partners can lead to a dismasting, so sound the whole deck and moisture-meter every fitting.
On early boats the shroud chainplates bolt to a plywood bulkhead that is not bonded to the hull, a configuration owners call unsafe offshore, and Practical Sailor recorded a chainplate pulling out of the bulkhead, so confirm the bulkheads are actually tabbed and probe them for rot.
The stainless chainplates pass through the deck and leak into the plywood bulkheads while suffering hidden crevice corrosion, and one owner's knee moved an eighth of an inch when someone jumped on deck, so treat any rust streak at the slot or any deck movement as a stop-work finding.
On early models the aft lower chainplates terminate in a plate held only by the deck and not tied to the hull, a known weak point, so verify this attachment has been reinforced or is sound.
The 1970s boats used galvanized cast-in J-bolts that have begun failing from rust and erosion, and a transverse crack owners call the smile opens along the centerline forward of the keel and leaks into the bilge, so inspect the nuts for section loss, check the bilge for rust staining, and sound the joint.
The skeg-hung rudder rides in a bronze shoe at the base of the skeg that suffers electrolysis when the boat is under-protected, so grab the blade for play, inspect the bronze shoe for wear, and confirm the sacrificial zincs are present and maintained.
The keel-stepped aluminum mast sits low where salt water collects and, with no original drain hole, corrodes and can weld itself to the step and bell out the base, so look for white corrosion powder at the base, a dished step, and any history of the rig going slack downwind.
The chronic complaint is overheating traced to the raw-water side (clogged strainer, worn impeller, fouled heat exchanger, or clogged exhaust elbow), and an engine that runs cool at idle but overheats under load points to a partial restriction, so motor at cruise RPM for 20 to 30 minutes and watch for black smoke.
The original aluminum fuel tank develops pinholes and pitting after about thirty years and fouls with algae sludge, which is a fire and pollution hazard and a chronic filter-clogger, so inspect the bottom and welds for weeping and check the fuel and Racor for water and mud.
The deck lands on an inward flange under a through-bolted aluminum toe rail (about 93 bolts per side) whose original sealant has dried out and whose voids let water track far from its entry, feeding the deck-core rot, so trace stains in the lockers and behind the headliner and check the toe-rail bolts for movement.
The full Islander 36 volume walks every point in depth, with the fix costs, the service data, and the parts sources. Leave your email for the printable checklist and word the moment the doors open.