Repairing the Pittarak
Occasionally we all do something silly in our kayaks.
It’s a bloody hole, mate!
For Lawrence Geoghegan it was parking his Pittarak on a rock in a nasty little gauntlet at Mystery Bay a few months ago and punching a big hole in the keel line just forward of the stern.
Lawrence made it back to the beach and rolled the kayak over for us all to see… on the beach we all stood around the kayak and shed a tear… you see, we wanted the bloody thing to sink!
Nah, just jokin’!
Cutting along the cracks to relieve fibres under tension
This article (and accompanying pics) shows how the damage was repaired. It may be useful for owners of composite boats who haven’t faced this yet! One of the good things about composite (glass fibre) kayaks is that just about any damage is repairable. Under my house is Mark Pearson’s old three piece Inuit Classic. It was originally a one piece kayak but it will be stuck back together one day without too much effort.
Back to the Pittarak. If this damage occurred during an expedition a liberal pasting with duct tape would most likely have been enough to seal the hole and complete the trip. Duct tape is good stuff for sea kayakers — always have some with you!
Preparation of the repair surfaces is the key to a quality repair job
OK, let’s have a go at this job:
The first thing to do is to clean things up and have a look at what needs to be done. It’s very, very important to ‘work clean’. This kayak may cross Bass Strait one day so the last thing Lawrence needs to deal with mid-Strait is a repair job coming away! I gave the boat a good wash in fresh water and dried it in the sun. Resin will not stick to salt-contaminated surfaces so clean it all up. I took all the gear out of the kayak (got a good price for it, too) and took off the hatches. When it was dry I vacuumed up all the sand that was in the rear hatch.
Planking over the hole along the lines of the hull
The hole was well back from the rear hatch so it wasn’t possible to look at the inside damage without sticking my head in the hatch. A retractable skeg is fitted to the kayak which further restricted access to the hole. A torch or lead light is useful for looking around inside hatches.
The damage: a big piece of keel line had virtually broken away from the boat. This piece itself was broken up a bit. I decided it was not to be used in the repair and removed it. In addition, there were several long cracks where the laminate had been flexed and broken but was still under tension — that is, it was pushed up a bit and the intersecting fibres prevented the crack from returning to the level plane. The fibres would have to be cut to allow the cracks to level out.
After removing the big piece I used a jigsaw to cut along the cracks. I carry a short piece of hacksaw blade for this job on trips. I then used my trusty angle grinder (wearing a dust mask) to round off most of the sharp corners. Coarse sandpaper was then used to ‘key’ the inside surfaces of the repair area. This is a very important part of the job. I vacuumed up the dust (work clean!) and wiped down the repair area liberally with acetone.
The repaired hull prior to filling of edges and flowcoating
I decided that I was going to repair the hole using 50 mm wide strips of chopped strand mat pre-wetted out with resin. The wetted out strips would be applied from the inside through the hatch with a small foam roller on a half metre long handle and would contact the ‘sound’ surface inside the hull at least half the width of the hole size all around.
Chopped strand mat is an ideal glass material for a repair like this. The fibres are random oriented so that there is good strength in all directions. The mat is easy to handle, cut and tear too. The fibres are held together by a resin-soluble binder. Once the mat is wetted out and applied, the binder dissolves, allowing the mat to be worked into complex shapes and into corners, etc. Chopped strand mat lays down pretty well too without too many annoying sharp edges to prick holes in dry bags.
I then ‘planked’ in the hole and cracks with several layers of masking tape along the boat. This ensured that the keel profile would be retained without too much sanding and shaping later. About four layers of chopped strand mat strips were applied followed by a light roll with a small metal roller to consolidate the layers.
Filled, masked up and sanded – and ready for flowcoating
When cured, the masking tape was removed and a filler used to fill in the cracks and to level up around the edges of the hole. I used Plasti-Bond but something like builder’s bog or similar would also do the job. A generous area around the repair was masked off and the whole area sanded smooth. Flowcoat (gelcoat containing wax) in a matching colour (in this case white) was then applied and the masking tape removed before the flowcoat gelled. The flowcoat/gelcoat is the waterproof and UV rays-proof layer in glass fibre boats.
All that needs to be done now is sanding of the flowcoat surface with fine wet and dry paper followed by a polish with some cutting compound… isn’t that right Lawrence?