Swing Keel
- Thread starter rlawson1
- Start date
Retrofit of another boat is only a narrow possibility if there other boats made from the same molds where the hull has the same hydrodynamics and righting moment, there by the keel will have the same dimensions and mass.
I am assuming you don't have the original keel, damaged or otherwise to copy dimensions from. Without a drawing it is difficult but possible to reverse engineer the dimensions from the keel pocket. You could make a new one from thick plate steel welded together, but will cost you big unless you are welder yourself.
I am assuming you don't have the original keel, damaged or otherwise to copy dimensions from. Without a drawing it is difficult but possible to reverse engineer the dimensions from the keel pocket. You could make a new one from thick plate steel welded together, but will cost you big unless you are welder yourself.
Post what you have and I can see if I can come up with something for you, a general plan or drawing to go by. Plate steel is not super expensive and if you have a buddy who has a welding rig (and you don't need a big one) you could probably build an excellent replacement for a few hundred dollars. Sand blast and paint with epoxy barrier coat and then shape with fairing filler... It could work.
That's even more simple than I would have imagined. Most of your ballast weight is actually in the trunk itself that is made of steel.
First you need to work on getting the remains of the old keel out of that trunk. I imagine the bolt in the side of the keel pin is rusted in place. It will be a challenge but you need to get that out. Hopefully you can remove the remains without it breaking up, but I imagine the rust has caused large flaking and expansion which has it bound up in the slot.
In any case, you'd need to get that trunk cleared up first, sanded and painted (or sand blasted). When that is accomplished you can reverse engineer the dimensions of the swing keel by making a foam board model first. It looks pretty easy judging by the pics, probably about 1/2" thick. Two pieces or 1/4" sheet steel could be cut with a plasma cutter to shape and welded together. The bottom bulb built up from additional plates. You won't even need fairing filler, the swing keel has no foil shape. Just a flap disc on an angle grinder will smooth out the leading and trailing edges as well as the bulb. You just need to focus on getting the overall dimensions right, especially the placement of the keel pin and the hole for the lifting eye.
First you need to work on getting the remains of the old keel out of that trunk. I imagine the bolt in the side of the keel pin is rusted in place. It will be a challenge but you need to get that out. Hopefully you can remove the remains without it breaking up, but I imagine the rust has caused large flaking and expansion which has it bound up in the slot.
In any case, you'd need to get that trunk cleared up first, sanded and painted (or sand blasted). When that is accomplished you can reverse engineer the dimensions of the swing keel by making a foam board model first. It looks pretty easy judging by the pics, probably about 1/2" thick. Two pieces or 1/4" sheet steel could be cut with a plasma cutter to shape and welded together. The bottom bulb built up from additional plates. You won't even need fairing filler, the swing keel has no foil shape. Just a flap disc on an angle grinder will smooth out the leading and trailing edges as well as the bulb. You just need to focus on getting the overall dimensions right, especially the placement of the keel pin and the hole for the lifting eye.
I cannot tell how badly it is rusted and /or deeply pitted. It could be that sandblasting the metal or wire burshing to get all the rust off, then spray zinc cromate on it, fill with two part epoxy and sand smooth, apply four layers of brrier coat and then bottom paint. Again cannot tell how far gone it is but if can be repaired, the steps above are the best approach to repair.