Styrafoam located in Hull

Discussion in 'Stability' started by mmarz4evr, Mar 8, 2011.

  1. mmarz4evr
    Joined: Mar 2011
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    mmarz4evr New Member

    Hi all,

    New to the forum and am no way near a boat engineer or expert! I have a basstender 9.4 (1980's) now made by KL industries. The boat is designed with an inner and outer hull and is made of some type of plastic. It has a thru-hull drain plug at the stern which can cause a little bit of water to get in between the hulls. This is very common in these types of boats, and they created a drain plug in the front of the boat so you can hold up the boat and remove any excess water after fishing. Well I got sick of doing that last summer, and decided to put a custom bilge pump in the stern of the boat on the port side. There is a compartment there about 12in x 8in x 8in sealed with styrofoam in it. There is a compartment just like it on the starbord side. If you search this boat online you'll see what the compartments generally look like. I can provide pictures as well. Anyway, I removed the styrafoam on one side in order to place the bilge pump. I haven't had the boat on the water since I've made the changes and I'm wondering if you think I've effected the buoyancy of the boat in any way? There wasn't a lot of styrafoam there and I did not remove it anywhere else.
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    If the outside of the boat is the same as it was, then you haven't changed anything, unless of course you plan on filling it with water, in which case you get a little more in her.
     
  3. mmarz4evr
    Joined: Mar 2011
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    mmarz4evr New Member

    Thanks

    Thanks for replying. I haven't made any changes to the outside of the boat/hull. I had to be careful about that when designing the bilge pump. I don't think under normal circumstances I'm fishing in water where I'll have to worry about flooding the boat because of rough waters or a wave(mainly ponds and small lakes), but if I did start filling with water because of a leak or something- I have a bilge pump now and hopefully that would keep it in check. Styrafoam or not, If the boat filled with water it doesn't seem like it would be a good scenario. lol I just want to make sure she'll floar the same way she did before i made the changes. I'm going to find out soon for sure. lol
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    On your boat you have a hull shell and a deck cap/liner which makes up the interior of the boat. Between these two big pieces of 'glass are areas of foam, to provide flotation if the boat gets swamped (for what ever reason).

    It's very probable that the foam used in your boat absorbs moisture, meaning any leaks will soak into the foam, making the boat heavier. I've repaired boats of that vintage, where it was carrying 500 pounds of water around with it, between the hull shell and deck cap. In most instances, this area doesn't have a drain so it picks up moisture, but can't get drain it off.

    It would be wise to arrange some sort of drain for this area between the hull shell and cap. Typically this will be near the transom, where there is usually a shallow well, where you've apparently placed a bilge pump. In a perfect world, you would remove the deck cap, then hack out the foam, replace it with a closed cell type, then reinstall the deck cap. This is a lot of work and most wait until the decks are soft and the stringers shot, then they replace everything as required.
     
  5. mmarz4evr
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    mmarz4evr New Member

    work

    yea i actually flirted with the idea of separating the hull shell and cap. When i started removing the rub-rail, i noticed there are industrial sized staples everywhere the hull shell and cap meet. I didn't even want to deal with the process of removing all 10,000 of them just to remove it!!! I would have also had to find a staple gun big enough to replace them. I went another route. Thanks.
     

  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The staples are easy to cut through and you wouldn't replace them. You'd use screws and/or a bonded flange instead.
     
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