Sharpie Design and Keel Weight

Discussion in 'Boat Design' started by marked77, May 17, 2010.

  1. marked77
    Joined: May 2010
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    Location: hudson, fl

    marked77 Junior Member

    I have just purchased a 37' Sharpie 1971 era. It is 9' beam and I just found lead sheets under the floor and needed opinions. Currently the boat draws approx 32" mostly due to a 12" fixed keel following the drop down keel towards the rear of the boat. It has twin 25' hollow fiberglass masts and is cat rigged. I am installing a 25hp 4 stroke in the engine well. Looks like it might have had a 10hp prior. My question is this. Would it be a bad idea to take out some of the lead sheeting and installing water balasts so that I can control performance . Water tanks full when sailing and pumping out while motoring...or, be able to add weight to the side of the boat that needs the balast. Boat is a blank canvas on the inside. Input? Picture is included. Thanks ps bottom is totally flat except for the 12 inch fixed keel.
     

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  2. marked77
    Joined: May 2010
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    Location: hudson, fl

    marked77 Junior Member

    Re 37' Sharpie in Tampa Bay Area

    I just sent a post that pictured a 2.5 4 stroke........I am installing a 25hp....not the 2.5 shown.
     
  3. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    The questions are...

    Do you know the designer of the boat? Perhaps its a good idea to ask him if he has placed the lead there and why.

    Do you have drawings of the boat and is the boat built after them? Then you can make a stability calculation to see how many inside ballast you really need.

    Genarally don't use water as the basic ballast to keep the boat selfrighting on 90° (or 120°) inclination. Sometimes it's not there in the moment you will need it to be there.

    Lead is 11,3 times the wheight of water in the same volume, so guess how much volume you will need to replace the lead, not counting that the lead is lying deep down and working on a relative good lever arm to keep your boat upright. Water will sit higher. BTW Is the lead well fastend to the hull?

    Waterballast is very good as additional ballast to trim the boat and to improve the sail carrying ability, but not more!

    Grrreetings from the North Sea Coast, Michel
     
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  4. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    By the way ... nice looking boat and very interesting too. Who has designed and or built it? Do you have some photos where the boat is sailing? Or some with more details?

    Michel
     
  5. marked77
    Joined: May 2010
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    Location: hudson, fl

    marked77 Junior Member

    Re Water Balast vs lead

    Unfortunately all the info I have is what you see. The lead is not attached..it is just lying un der the floor. I did keep n mind the potential shift of weight distribution with water but can buy tanks which are long and slim, which will make this difference minimal. I guess the good thing is, the tank system is very inexpensive and if I take lead out, I can always replace it. also, I probably (in most cases) empty the water balast if motoring....but thanks for the input. I have very minimal money in this boat which allows me to experiment with performance, the sails reef very easily, and the center of gravity is very low since the rig is cat with roachy sails. Also I sail in the Gulf of Mexico which is quite calm compared to most areas. If I do it, I will post results. At least I can pull out the lead if I need to pull her out on a trailer! Take care Mark ps since this is really just a day sailer..maybe I should add some large amounts of foam for my experimentation! Take care:) :)
     
  6. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    estimate the mass of the lead. How much is it?

    Michel
     
  7. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Pinky sharpies like that require the lead or they will loll and perform badly. Usually they were ballasted down to just bring the bow and transom to the waterline so as they heel the chine provides the lateral resistance. Deballasing for motoring may pound her apart as the structure is not designed to be driven into chop while upright, they were designed to be sailed slightly heeled to reduce pounding.
     
  8. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    She floats on her lines. Taking out ballast will make the boat perform poorly and increase the risk of capsize.
     
  9. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    Forget about the water and the foam ... fasten the lead! If lead is flying due to heavy heeling it becomes a bullit, able to perforate your hullsides

    Michel
     

  10. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    Marked77, the gulf is not as tranquil as you suggest. Sure it is not like rounding the horn but it can and does get very mean, very quickly. Even supposedly sheltered places, say like Sarasota Bay, can range from merely unpleasant to downright threatening. Sail a little way north of Tarpon Springs and there are very few places to seek shelter for one helluva long way.

    Fasten the lead in place. Securely. If not fastened the lead will fall to the low side in a knockdown. Just where you don't want it to be.

    I have an unabiding dislike for boats that contain lead. However, there are many boats that work better with it than without.

    Good looking boat, use it well, play it safe.
     
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