R 22

Rhodes 22


Dinghy Repair

I have a WaterTender polyethylene rowing dinghy that has developed a leak at the bottom of the keel. I've tried patching the leak with epoxy, which works for a while, then starts leaking again. Can this boat be saved?

If it's time to get a new dinghy, I've been looking at the Walker Bay 8 polypropylene dinghy. Has anyone had any experience with this boat?

Bill Effros
15 Feb 2000

Patching polyethylene - ouch! I believe there is a sealant or adhesive product made by Loc-Tite Corp. that is supposed to bond to polyethylene. I'll look up the product code tomorrow at work and get back to you. I would take some polyethylene sheet stock and make an inner and outer patch considerably larger than the hole. I would attach the patches to the dingy using closely spaced aluminum pop rivets with washers and using this Loc-Tite sealant product in between the inner and outer patch and the hull. If this patch ever wears out, you could drill out the pop rivets, peal off the worn-out patch and install a new one.

Roger Pihlaja
S/V Dynamic Equilibrium
16 Feb 2000

The Loc-Tite product that will bond to high-density polyethylene is:

Label Name Loc-Tite Product Code
Primer 77018396 for 1 fl oz
Loc-Tite 40140140 for 20 g.

Any industrial plastics distributor will probably be able to sell you Loc-Tite products. Loc-Tite makes about 75 different flavors of specialty adhesives. You won't believe what they will charge you for these two tiny bottles of juice! But, this stuff works as advertised and the small bottles will probably be sufficient to do your job unless the area of the patches is several square feet each. Read, understand, and follow the personal protective gear precautions on the Material Safety Data Sheets (MSDS) that will come with each bottle, as I wouldn't want you to grow a 2nd nose or something! If they don't give you an MSDS with each bottle, then ask because they are required by law to furnish them to you.

You will have to apply the primer to both surfaces & then the 401 adhesive. This material is sort of like a "contact cement" for polyethylene. For underwater use, it is recommended to run a bead of Dow Corning Silicone Aquarium Sealer around under the edge of the patch to prevent water intrusion into the joint. Use one of the pigmented flavors of silicone sealant, as the clear will have much less UV degradation resistance. Make sure the polyethylene sheet you use to make the patches is also UV stabilized or the patches won't last very long in the sun.

I would still recommend the inner and outer patch method mechanically held in place with pop rivets as detailed below. This repair method will keep the adhesive/sealant joint in permanent compression for reliable leak-proof performance. It will actually make the hull stronger in the vicinity of the patches, and could be repaired if a patch wears out.

This is my best shot at repairing your dinghy. If this method fails, then I would junk it.

Good Luck!

Roger Pihlaja
S/V Dynamic Equilibrium

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