Todays Survey this Knysna 480 cruising catamaran. To save weight, the use of Airex foam coaring was used in the hulls, deck and bulkheads. Components are hand laid and vacuum bagged using isophthalic gelcoat and vinylester resin. A fiberglass grid set into the lower part of the hull helps accommodate rig and keel loads under sail, and supports cabinetry, the cabin sole and other below decks structures.

Layout gives four cabins outside the saloon with eight berths in total. The spacious interior provided comfortable, live-aboard facilities for extensive cruising.

 

On close inspection we found many cracks in the bulkheads around most of the door frames including the patio door into the main companionway. Recommendations concluded was to remove the door frames, grind back a 120mm taper each way and re-glass. The full laminate in the middle tapering each way, for the whole length of the crack + 60mm approx. The recommend that if Bi axial tape is available it be laid  + and – 45 deg to the line of the crack. The top layer can be light mat for grinding to smooth & match the surrounding surface as best as possible. This repair to be done both front & back, and if possible across the cutout in the corners, so the material forms a continuous flange. The dry weight of material should be 900 Gr each side. If possible epoxy resin would be preferred since you are laminating over old substrate.