Monday night my friend's 23 plywood sportboat came "untied" from it's mooring on the Thames River in New London Ct. The boat drifted out of the river, across the sound, throught the "Race" and onto BOULDERS on the NE end of Gardner's Isl NY!
When the owner arrived on the scene at peak high tide, Gnat was high and dry, resting on it's port side. The carbon fiber keel was supporting the boat with the bulb in 1 ft of water, hull in 9" of washing machine froth. Three people made a heroic effort to get Gnat off the rocks and back in the water. Using a 4x4 they found on the beach, they used the keel to lever the boat back in the water. Once lifted, the keel was layed on a large boulder, one man hanging from the tip of the rig to help lift the keel out of it's rock wedged placement. Once the keel was on the rock, the lever was placed under the port side of the hull at the transom to lever the boat toward the water as the power boat snatched the little plywood boat over several massive boulders.
Once in the water, it was a scramble to get on the boat, collect the gear they used and heel the boat over to starboard to keep the holes out of the water. Just amazing to say the least. The owner also built this boat himself in '79. The boat was restored in 92 and heavily modified '03 to '06.
I built a carbon fiber keel for the boat to replace it's dagger board. A very deep carbon rudder was completed this summer. The keel was built using a prepreg carbon post I built for a 38 ft boat, but modified the laminate based on certain engineering issues, etc., with the 38 ft boat. It is only slightly ironic that the strength and structure that kept that keel in Gnat came from a boat whose keel failed. The post was not the only structure in the keel, redundant structure was thrown at it to give us some comfort. The keel without the shop poured bulb weighs roughly 50 lbs, bulb (won't give exact amount) between 450 and 550 lbs.
I hesitated to post this, but I think it is oddly appropriate because this is a true lightweight boat, not some (VERY heavy) cruising boat called ultralight. There is not a piece of steel in the keel, not any fasteners at all. The strength is gained by bringing the keel into a box with no possibility of wagging on a sump. It is my personal (not an engineer or designer, simply the guy who makes these things as over stated in press) that sumps are the root of all evil, I am not open to discussion on this!!!!!! Sumps allow for a place to put a bilge pump and keep water from sloshing around the boat as it heels. Sumps make for difficult laminating and misdirect fibers( again, argue all day, it is still POO! Sumps are evil!) It's simply amazing that proper fiber orientation allowed a 50 lb (2" cord!!!) plank of structured carbon could be used as such a violent tool without any structural damage. The hull cracked two inches forward of the keel, it appears to be minor and easy to repair. When modifying the dagger trunk, I noticed some "bad" wood and chose the easy fix, which has come back to bite me in the arse. The bulb had it's laminate ground off, but the two part bulb is still bonded(epoxy and cabosil, no cotton, no other wierd additive...I only use cabos sil for structured and bonding putties. Cotton and other crud stays too clumpy for my simple brain.)
I broke my silence to post this as it debunks the notion fin keels fall off because of their shape etc. They fall off because someone screwed up, PERIOD!
It was funny watching people drive up saying they heard the boat had been holed, but it looked fine.............until they see the port side.
Boat owner, Kevin Farrar Farrar Sails in New London.
Oh, the 13 lb, 4 ft deep, all carbon (not a carved piece of foam core, they break) rudder did make landfall as well with minor dings.