Join Date: Aug 2006
Location: Grand Rapids, Michigan
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Re: Island Packet and Cape Dory 33- 40 range.
Another interesting unique feature of IP's is that they use proprietary resin "Polycore" filler for deck core instead of balsa or other wood. Not sure if this is better or worse than anything else, but I like the idea of not worry about rotten core.
Here's a few more IP construction details from BW Sailing:
"Unlike many fiberglass boats, the Island Packet hull is made in one piece, including the keel. Cast lead sections are lowered into the matching cavities and laminated over using more triaxial fabric. The hull is roughly an inch and a half thick at the turn of the bilge, tapering to half an inch at the hull flange.
With the hull sitting outside the mold, a grid is dropped into place, serving the purpose of a hull liner and doubling in brass as floors. This liner/grid is a structural element, and is cored with what IP calls Polycore. If you think of it as microballoons contained within a polyester foam you won’t be too far off. It has the quality of being resistant to water intrusion and is blessed with a very high strength-to-weight ratio.
The floors are an engineered structural grid, referred to as an Internal Glass Unit. This IGU, part of the liner, contributes to the hull’s strength.
The deck is also made of triaxial fiberglass, changing to biaxial in places where a pronounced curvature would make the triaxial unsuitable. The flat parts, in addition to being made of triaxial, are also cored, with the same material as used in the hull liner.
The important thing is that the core is structurally identical to the fiberglass, so the fiberglass and the core stretch and contract due to stress at the same rate, minimizing delamination. Island Packet has been using this method of lamination since 1984, and in 1992 they began to provide a 10-year warranty against deck delamination. It seems to have been a safe bet: so far, there hasn’t been a single claim.
The keel is unashamedly full. In a world of bulb-fin keels, canting torpedoes of lead and keels with trim tabs, the IP full keel has the simplicity of a hockey puck. It’s there, it’s the full length of the boat, and it even has the rudder fastened to it. Island Packet’s explanation is that this is a FullFoil keel, i.e., its shape develops lift to windward, and that the advantages of a full keel, especially when shaped as a “full foil,” more than offset the drag caused by the wetted area."
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