Adding a Keel to a wooden boat

Discussion in 'Boat Design' started by Jomac, Aug 17, 2021.

  1. Jomac
    Joined: Aug 2021
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    Location: Ipswich UK

    Jomac New Member

    I'm looking at purchasing a 1947 River Cruiser which has no keel to speak of. The boat was originally a holiday hire boat on the Norfolk Broads. I am planning on sing this boat as a live aboard capable of coastal and the occasional trip across the English Channel in good weather. With the boat being pretty flat bottomed, I am considering adding a keel to improve the stability, probably bolted to the main spine or backbone that protrudes about 4" from the bottom of the boat.

    I have very little experience in this area and I'm looking for advice and tips to try and reduce any rolling in anything other than river sailing.


    TIA
    5057918.jpg IMG_20210803_162620.jpg
     
  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    Welcome to the forum, John,
    The keel, by itself, will not increase the stability of your boat, although it can soften the roll period. A weight as low as possible, on the new keel, or in the lowest part of the current keel (longitudinally well placed) will improve the initial stability.
     
  3. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Looks to me like it already has a keel?
    You want to make it deeper?
    Why does it need more keel?
    An old wooden boat may not be the best candidate for modification that will increase and redistribute stresses.
     
  4. wet feet
    Joined: Nov 2004
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    Location: East Anglia,England

    wet feet Senior Member

    Unless you had a thorough survey done prior to purchase,I think you should exercise extreme caution about venturing very far beyond Shotley with that boat.It was built almost 75 years ago and would have been intended to earn a living.consequently the build would have been sufficient for a boat that would never encounter much more than waves a few inches high and I would be pleasantly surprised if the builder used non-ferrous fastenings-some did,but not too many.Normally old hire boats were sold on when the cost of keeping them in the fleet crept up and reduced their earning capacity.The framing would have been sufficient for the local waters and I would imagine the bulkheads are tongue and groove boards over light frames.Which means the structure would flex a bit at sea,even when quite new because it was never intended to be there.The inevitable effects of age on a boat built to withstand only modest levels of pitch and roll are likely to have made it more flexible and any additional keel will only have a small effect on torsional stiffness.I would say the boat is much better suited to remaining in flat water than to exploring the open sea and I am aware that some days see flat seas,at least for a while.If you have solid evidence of a good level of integrity or reports from a fairly recent restoration you could act accordingly.
     
    Last edited: Aug 18, 2021
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  5. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Can you post a side profile view of the boat please Jomac, which better shows the existing keel?
    And if you have any other photos of details, can you post them as well please?
    Re how you are 'looking' at purchasing this boat - don't be too hasty.
    If you have not had a full survey carried out on the boat, have one done first.
    If you are deterred by the cost of the survey, you cannot afford this boat.
    How much are they asking for her?
    Re the hull bottom photo, the seams shown appear to be rather 'ropey' (if I may use a classic English expression). And the propeller looks like it has seen better days.

    If you want a boat to live on, one which is capable of doing coastal passages, you would most probably be better off with a much more recent fibreglass boat.
    What is your budget?
     
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