Latest News: Forums Technical Help Leaking buoyancy compartment (front)

  • This topic is empty.
Viewing 10 posts - 1 through 10 (of 10 total)
  • #4165

    Hi could anyone help me with this ?

    I just opened my front buoyancy compartment and discovered a rather large puddle , after draining out allot of water from the bung infront of the centreboard casing i am rather concerned about this problem as my boat will be kept on a mooring . The boat has not been on the water for a while and the only water that is in the bilges is the small amount that has got through my rather tatty cover , the water sits right at the front of the boat so i have come to the conclusion that the water must be able to get through the join between the bottom of the hull and the front bulkhead .I can not see any major points where water could get in . Please could someone help me as i am rather concerned about the amount of water that had found its way in (it was dry last time i checked it . Is this an easy fix (my boat is grp) please help :S 😳


    Make sure the hatch is on tight and hold a vacuum cleaner that blows or lilo inflator about 2″ from the bung hole. Careful not to hold it too close or you’ll blow the tank up you just want to slightly pressurise it. Make up a solution of 10% washing up liquid with water and paint on all the seams going round thoroughly. Swiebertje blows but I like to look for the leaks at my leisure and without passing out! You’ll get bubbles where the leaks is/are. Alternatively use smoke pellets from plumbers merchants on a tin so you don’t burn the boat. To mend use eopxy/silica filler making sure surfaces are dry (hair dryer) and abraded as best you can or maybe sikaflex. Make sure as well as testing deck-hull join and bulkhead you do bottom brass rubbing strip as screws can cause leak along keel. Good luck – it shouldn’t be a massive job! Robert


    Thanks Robert.

    would it be ok to just go all the way along the seam on the hull floor with fibreglass matting and epoxy or polyester ?


    It would help if you tell us what type of Wayfarer you sail.

    In general the inspection hatch is the most common culprit. The rubber seal needs to be replaced every few years and the hatch itself often becomes brittle after e few decades. If cracked, replace the entire hatch. On a mark2 for example, the vertical part of the bulkhead to hull connection often has some leaks after a collision. Specially with older boats the glue may have become brittle. If the leaks are small they can be quickly fixed with some MS polymer sealant (e.g. Sikaflex). Only if the bulkhead is loose, and can be moved relative to the hull by pressing it, you would need to re-glue it with some of that thick epoxy glue. AFAIK no glass is needed with this type of glue. Give Ian Porter or another GRP specialist a call for the exact type of glue to use. But I have yet to see such damage, all cases I have been involved in have been fixed with a dab of sealant.

    For testing I have devised a device that plugs in to the bung and connects a garden hose air tight to the tank. Regardless if you use soap or smoke pellets you need to pressurize the tank to find leaks. I find blowing to be easiest and quickest. Just a few puffs are sufficient.

    The picture shows a part of my buoyancy measurement kit. The garden hose is connected to an angled copper pipe to ease the insertion in to the bungs without having to remove the floorboards. The copper pipe fits exactly in one of the pre-drilled bungs that replace the boat’s original bung. A little petroleum jelly eases the copper pipe in and ensures an air tight seal. I have several pre-drilled bungs and corks to fit most of the boats.


    It is a mk2 and at the moment i know this particular leak has absolutly nothing to do with anything above the floorboards because the boat has only been on my drive and the people i bought it off had not sailed it for 20 years , so i am certan it is to do with the join between the hull and where there is the perpendicular join to the bulkhead , so should i just go along that join with silkaflex or would a bathroom type sealant be acceptable ?

    Colin Parkstone

    Watch Out Dom!
    The Dutch Sikaflex lover 😡 will be along in a second with tails of Doom and Gloom about bathroom sealant, he is right as it is not too good in the long run!

    If you have time and want the job to last the season, glass tape and resin is a good way to go but do abrade well before hand.

    A trick to use when bonding a tank edge is to put some form of vacum to the tank when you wet out the grp/resin, it will pull some of the resin into the gap and help to seal it better.

    Try a mix of resin and resin filler first,suck it into the gaps then stop the suction,then bond the joint.

    I am not sure about Sikaflex as a gap filler, more of a bonding glue I would say.

    C P 🙂


    Thanks colin.

    I thought that the epoxy route would be more dureable , so i just need some fibreglass matting or tape , resin and maybe a filler ? Also should i use epoxy or would polyester be better ?


    Hmm, sounds like a major repair job.

    Before starting you may want to check the mast step. A lot of rain water comes in to the boat along the mast. The mast step screws could leak water in to the tank.

    Some older MK2’s did not have sufficient support for the mast and the GRP below the step could have cracked. The worst case I have seen was a mast that sank about 10 mm in to the supporting GRP. I am not saying your boat is one of that series but it would not hurt to check for cracks under the mast step. If however, you do have one of these boats you are in for a nasty repair. You need to laminate a piece of wood under the mast inside the tank, through the inspection hatch. It sounds impossible but It has been done. See here:
    and here:

    What I am trying to get across is first look for the simple problems and simple solutions and only if they fail go for the major repairs. Find the leak with some soap and then decide if it needs major repairs or only a quick fix with some sealant.

    If your boat has been stored ashore your leaks could still be higher up. Water has a nasty way of finding its way in to the tank. Rain comes from above and under a cover it could also be condensate leaking in to a the tank. Maybe a few drops at a time but after 6 months that could have accumulated in to several liters. Or maybe it is just a case of a poorly closed bung?

    P.S. Blame Google for the poor translations.
    And to please CP: Never use anything on a boat that starts with the word “silicone”.



    Thanks for that , i think there are a few cracks on the mast step , they do not look to drastic though , personally i would nott feel all that compitant takeing the piece of wood out through the inspection hatch , so as i will need so epoxy and matting to fix the leak along the seam could i not repair the step with this , i think i should be ok as the problem there does not appear to be all that bad , or would this not be worth dooing ? thanks for your help.


    The advice to find the problem by testing is very sound.

    I had a similar problem a couple of years ago, which proved to be due to a couple of screws on the keelband that had pulled out.

    I hadn’t noticed that the keelband on my boat was in several sections; a short section caught on something, probably the slip while awaiting a trolley, and pulled out a couple of screws. I replaced the whole band, since having it in sections seemed daft, but all that was necessary to stop the leak was to properly seal the screw holes.

    good luck

Viewing 10 posts - 1 through 10 (of 10 total)
  • You must be logged in to reply to this topic.