Bowsprit Tube Leak Repair
March 12, 2018 at 3:09 pm #10114
If your main hull is mysteriously full of water the only known ways water can get into the main hull is either through the inspection hatch, through the drain at the stern or through the bowsprit tube in the bow (especially after impact to the bowsprit).
The tube is quite light and is used only to keep the water out of the hull. The loads from the gennaker and the sprit are transmitted to the hull at two bearing points only. The fore one is at the bow at the junction of the hull and the deck and the aft one is a 20 mm deep cup moulded into a hidden bulkhead about 600 mm back from the bow.
The bulkhead is inaccessible from the existing inspection hatch behind the mast because of another bulkhead.
– Try the filling the prod tube with water from a hose to see if the water is leaking through the base of the tube.
– If you have one, attach an action camera (e.g. XM Warrior) to a pole and push it inside the tube then shine a torch down to take video of any cracks. You may be able to use a phone camera with the flash on fully zoomed to be able to see any damage.
If it’s a really serious leak and you hear a crunching sound from the pole when inserted fully, then you many need to cut into the deck to repair the bulkhead and the tube mounting. The hole in the deck can be sealed with another inspection hatch or (if you’re skilled and have time) with gelcoat to match the existing deck.
If it’s a small leak you may be able to repair it by pushing a resin-infused carbon patch down the tube.
- Carbon weave mat or fibreglass mat
- Resin and hardener
- Digital kitchen scales wrapped in cling film (for resin/hardener measurement)
- Bulking agent to thicken liquid resin (e.g. microbeads)
- Paint brush to fit inside tube
- Resin mixing container and stick (disposable cups and plastic knives work well)
- Acrylic/Polythene film for lining tube walls or a length of 40mm PVC waste pipe.
- Dowling or pole rto create long handle for brush
First ensure the tube is clean and dry. Use a rag on the end of a pole dipped in acetone to clean the surface.
- Mask off the bow and trolley with packing tape/polythene to protect from resin
- Measure the depth of the tube and buy acrylic/polythene film (thick enough so that it keeps to the walls when rolled) and insert that as a liner in the prod tube so that it’s touching the bottom of the tube.
- Cut out a circular patch of carbon weave cloth to fit the circumference of the bowsprit
- Tape the brush to a pole long enough to reach the base of the tube
- Mix resin and hardener with a thickener to create a paste
- Use the long handled brush to coat the bottom of tube
- Infuse the carbon patch with resin using the brush and use the adhesion of the resin to hold the patch folded over on the end of the brush
- Push the patch down to the base of the tube using the long handled brush and agitate it to tamp it into place – check with a phone camera with the flash on that it’s properly seated
- Allow to cure slightly before removing the tube lining
- When cured, repeat the hosepipe test to ensure your repair has worked
If the above doesn’t work or your damage is more extensive, you’re going to need to cut a hole in the deck to repair the bulkhead and seat the bowsprit tube against it, reinforced with fibreglass or carbon.
For an emergency repair, cut the hole to fit an inspection port so you can fit the port after the repair and get back on the water.
For a better repair, fill the hole with a fibreglass patch and apply gelcoat to match the deck as shown in the photos below.
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