Our sailing waters near Brisbane in Australia are shoal and subject to areas drying out with accidents running aground on falling tides commonplace. We are considering foregoing pointing ability of a 340 and modifying a shoal draft wing keel to a 4' draught by using a bulb attached to the lower 12" to compensate. The wing keel is potentially dangerous if caught aground on a falling tide. Has anyone any experience or knowledge of the amount of weight we would have to put back on to the remaining keel in relation to the weight taken off? Would it be an equal amount or would it need to be increased by what percentage to have the same righting moment and stiffness? Also any ideas on materials and methods of fastening?
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It's been done before!
A frined who runs a charter company shortened the keel on his Express 35'. He cut 18" off the bottom, weighed it then calculated the extra wieght needed to return the same foot pounds of righting moment. He then had a lead bulb cast in two halves the inside profile to match the shape of the remaining keel. Then set these pieces onto the keel with epoxy and through bolts. The whole job cost him about $4,000 US. As the keel is bolted onto the hull and faired using epoxy this method seams reasonable to me, and has caused no problems to date! Just get a good yard to do the work.
A frined who runs a charter company shortened the keel on his Express 35'. He cut 18" off the bottom, weighed it then calculated the extra wieght needed to return the same foot pounds of righting moment. He then had a lead bulb cast in two halves the inside profile to match the shape of the remaining keel. Then set these pieces onto the keel with epoxy and through bolts. The whole job cost him about $4,000 US. As the keel is bolted onto the hull and faired using epoxy this method seams reasonable to me, and has caused no problems to date! Just get a good yard to do the work.
Mars Metals
I know this has been done begore, and there is a company that specializes in adding bulbs to keels. I seem to recollect the company as "Mars Metals" , and I am positive that they are in Hamilton, Ontario, Canada. There were some pictures of this I saw somewhere, can't quite remember, but it may have been cruising world about three years ago. Good luck, Dave
I know this has been done begore, and there is a company that specializes in adding bulbs to keels. I seem to recollect the company as "Mars Metals" , and I am positive that they are in Hamilton, Ontario, Canada. There were some pictures of this I saw somewhere, can't quite remember, but it may have been cruising world about three years ago. Good luck, Dave
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