The owner of this 38ft sailing catamaran asked us to check out some what seemed to be minor ‘cosmetic’ repairs mainly in his cockpit and a few on the hulls. Once we started digging we discovered that moisture had got into the balsa core and traveled an alarming distance. Once we had established the extent of the repairs which consisted of a large area on the Port side of the cockpit seat that had spread into the backrest and the deck aft of the seat, another smaller area on the opposite side of the cockpit and both engine hatch tops which are part of this seating. During this work the owner asked us to inspect a crack he had found while preparing the bottom for antifouling. The small crack was in the bottom of the daggerboard case and after further investigation turned out to be a large section of wet balsa core that extended upwards approx 300mm. This was also cut out and repaired. To replace the balsa core we used Divinycell foam core which is a closed cell structural core. It can’t absorb water or rot and was glassed over with epoxy. However the seatback was 4mm marine plywood which was replaced and coated with multiple sealer coats of epoxy resin. Once repairs were faired and primed, we rolled and tipped all the paintwork in the original paint to match followed by the nonskid panels. The various paint repairs around the hulls were also repaired. Once the job was completed there was no sign of any work being done, a sign of a well finished job. Because the rotten area on the Port side was below the mainsheet track which is subject to very high loads, the owner was very relieved to have found and repaired this area bringing his boat back to full strength once again.