A good friend of mine just purchased a Valiant 42 which draws 6'-0". The boat is in a marina in Sandusky, Ohio. Because of a lack of rain and snow over the past few years, the water level in Lake Erie is 18" below normal. To move the boat out of the marina after it's launched, he will have to pass over a mud bar that has only 4 1/2' of water. His question to me was "How much will I have to kedge the boat over to raise the keel enough to get over the bar?" My rather unscientific guess was in the range of 40 to 45 degrees before the keel raises that far. Would anyone have a better guess? Or is there a formula to calculate the amount of heel required? This isn't critical but I figured you guys would enjoy thinking about it. Thanks, Jim.
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Kedging over
- Thread starter cavale
- Start date
A couple of years ago a friend had run his Ericson 29 aground to avoid sinking when his stuffing box let loose. I used the club launch to pull him off with a line to his main halyard which we raised to the top befor the pull. At any rate, he had water up to the point where the coach roof goes up from the deck. The deck at iots widest part was fully under water. Another thing to realize is that when the boat does start to moove it will want to move forward, even though the pull is from directly abeam. 40 to 45 degrees ia about what i saw. Hope this helps. Bob
<div>Jim, I had always thought that with a set of scantlings, a marine architect could compute this type of thing. Maybe not.
I have a six foot draft M382 and have been concerned about hulling when operating in the Georgia and NE Florida coastal waters where tidal ranges can be six or seven feet or more. Some years ago I called Morgan Yachts for information as to what the water level would be as the boat hulled and then refloated. In other words would the boat flood either through the companionway or the port locker under the cockpit seat.They were not able to answer the question. They said they had no experience with this type of thing???? Standing at the stern with the boat out of the water and sighting forward, the water line I imagine does not give me any warm fuzzies.Dick
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I have a six foot draft M382 and have been concerned about hulling when operating in the Georgia and NE Florida coastal waters where tidal ranges can be six or seven feet or more. Some years ago I called Morgan Yachts for information as to what the water level would be as the boat hulled and then refloated. In other words would the boat flood either through the companionway or the port locker under the cockpit seat.They were not able to answer the question. They said they had no experience with this type of thing???? Standing at the stern with the boat out of the water and sighting forward, the water line I imagine does not give me any warm fuzzies.Dick
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carl_miller
Carl Miller
Well, Its been a lot of years and the sci.calculator is long gone BUT:
I figured given: that the |(vertical leg = A); _ (Horizontal leg = B), using a right triangle then A = 6.0'( the keel) and B = 7.5 ', the keel draft plus the needed 18", then sin angle =6/7.5 = .8. then I had to go to Excell and try to convert from radians (whatever those are) to degrees) and came up with 46 degrees and a scosh. A lot of trying to reopen some old ancient synaps to prove that your gut feel was correct.
I figured given: that the |(vertical leg = A); _ (Horizontal leg = B), using a right triangle then A = 6.0'( the keel) and B = 7.5 ', the keel draft plus the needed 18", then sin angle =6/7.5 = .8. then I had to go to Excell and try to convert from radians (whatever those are) to degrees) and came up with 46 degrees and a scosh. A lot of trying to reopen some old ancient synaps to prove that your gut feel was correct.
Assuming as you healed the boat, the buoyancy remained about the same, then you have a right triangle with c=6' and a=4.5'. Using Cosine, you would get something around 41 degrees if my daughter read her calculator correctly. I'm thinking the buoyancy would increase and 'lift' the boat a little higher reducing the angle to less than 41 degrees. Good luck. Maybe it will rain soon.
Thanks, Everyone for your replys. My friends solution at the moment is to have two tow boats. One to heel the boat by hauling down on the mast and the other to pull her by the bow across the bow. His wife tells me he is also doing rain dances in the living room. I'll let you know how it works out.
Do what hornblower did at the battle of Riga with his bomb ketches. Tie two fully-ladened (water would be best) , flat bottomed barges to the vessel sides and under her keel. then, pump out the barges. As they rise, they will raise the vessel's draft. Of course with a Valiant, they will have to be big barges, so maybe a solution that worked for the English Navy in 1811, when labor was cheap, will not work for you. Good luck.
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