Forums Forum Transom flaps

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    • #20093
      t2bois
      Participant

      Good evening,

      I’m a owner of a early GP14, and I’d like to know how to drain the boat properly ?

      Do you have any tips or do you know if it’s possible to buy a kit somewhere  ?

      Are they rules ? Official dimensions ?

      Thierry (Belgium)

    • #20094
      Oliver Shaw
      Moderator

      By early I presume you mean Series 1,  or GRP prior to the introduction of underfloor buoyancy.

      If you are referring to getting water out of the boat while sailing there are two options,  intended to cope with two different situations.

      Transom scuppers are intended for getting large quantities of water out of the boat after a capsize,  and doing so very rapidly.   To my mind the jury is still out as to how well they work on the early boats,  but I am assured by others that they do indeed work;  however my one experience of attempting to empty a deliberately flooded boat in a test situation suggests that it is absolutely imperative that you have plenty of buoyancy in the bow,  and the bare minimum permitted under the class rules is not enough to enable transom scuppers to work.  I deliberately flooded my then boat,  and tried to sail her dry on a reach,  but all that happened was that when I sheeted in I drove the bow underwater;   so I then replaced the bow buoyancy bag by the largest one which I could fit into the available space,  but I never put the scuppers to the test again.

      But undoubtedly the transom scuppers work staggeringly well on the Series 2 boats.

      The basic requirement is two large holes in the transom;   that is all,  but for best practice (and to comply with class rules) you also need a means of closing them.   The Class Rules (available in the Members’ Area of this site) specify the position and the maximum size,  and for the early boats they must be circular to comply with the rules.   The most popular means of closing them are flaps of any sheet material,  hinged to the transom at one side (gaffer tape will do for the hinge,  although you may prefer something more sophisticated),  and with a length of shock cord to pull them closed.   An alternative,  rarely seen,  is a pair of conical funnels which seat in the holes,  again held in place by shock cord.

      Be aware that the transom scuppers will not be at the lowest point in the hull when the boat is correctly trimmed.   You will probably also find that when the boat is half full of water you need to sail her fairly broad on the wind to get the scuppers to work.

      Self-bailers are normally fitted in the bottom of the boat,  approximately amidships (just abaft the thwart),  adjacent to the hog;  this will be the bottom of the boat in normal sailing trim.   There are many different types,  but the best are probably the Andersen type,  previously known as the Elvstrom type.  It is worth having one each side,  and going for the largest that you can afford.    Unlike the transom scuppers,  they will remove all the water in the boat,  and they are the primary tool for water taken aboard as spray,  or dare I suggest leakage;    but they will take much longer than the transom scuppers to empty a half-full boat after a capsize.

      Different tools for different jobs,  and you may need both.

      For draining rainwater out of the boat when ashore the old traditional approach is a pair of drain bungs as low in the transom as possible,  and prop the boat with the bows up so that all the water can drain out.    Alternatively chock her level and leave the self-bailers open,  provided that your launching trolley permits them to be open;   with some boats and some launching trolleys the self-bailers are obstructed by the launching trolley cradle.

      Hope this helps,

       

      Oliver

    • #20095
      norman
      Participant

      Hi, I can vouch that transom flaps do work on older boats though you may need a force 4 or more.  If it’s lighter you may have to rely on a bucket, though I was once towed dry by a kind rescue boat. A sizeable bucket is a good second line of defence and take note of Oliver’s point about more than minimum buoyancy provision.  The flooded boat needs to float high enough for the top of the centreboard case to be above water level or else it can come in faster than manual baling takes it out. With regard to self balers, it is my impression that the Allen Delta balers on my current boat are more effective at low speeds than were the Elvstrom balers on previous boats, but I have no objective information.

      Hope you get sailing in Belgium sooner than looks like being the case in Scotland.

      Norman

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