Thursday, July 5, 2012

Replacing the Romany Kayak Seat – Fixing a Leak Under the Seat caused by the “Grinding” Effect

The shocking truth revealed - the Grinding Effect - wear areas under the seat

Sad as I was to do it, I had to take a hack-saw to my 2008 Romany Sea Kayak yesterday because it had developed a leak under the seat. I’ve long been aware that sand/pebbles under a fiberglass seat hung from the coaming can grind away at the hull. But despite my best efforts at clearing the debris out after paddles, on my last few paddles I’d noticed the cockpit was a bit wetter than it should be and suspected a slow leak. Sure enough, when I filled the cockpit with water an area of star crazing in the gelcoat beneath one butt cheek was drip, drip, dripping.

The photos below show me hack-sawing the seat out and the very revealing amount of wear beneath the seat where it makes contact with the hull - like it had been sanded down by a grinder – amazing. My intention is to use Epoxy on the inside to fix the leak, then refinish the gelcoat on the outside hull. In the past, I’ve done all my repairs with polyester resin since that’s what most fiberglass sea kayaks are made with (both for laminating the fiberglass layers and in the outer shell of gelcoat). Years ago I also worked extensively with MAS Epoxy resin when building a wooden kayak and had good results. Epoxy resin is said to be more flexible and water tight than polyester resin but may not provide the same adhesion to the existing polyester gelcoat on my boat (?). I have a few small repair packs of West System epoxy that are cheap and convenient so will give that a go this time. Update: Epoxy is sticky stuff and is doing just fine in the repair patches, and the layer of polyester gelcoat I put on the outer hull side seems fine against the epoxy on the inside. In other words, for basic fiberglass kayak repairs, epoxy is all I'll likely use in the future. Nick Shade, a CT boatbuilder I know, once said using epoxy exclusively for all fiberglass or carbon kayaks is fine, and for repair of the gelcoat outer surface he suggested simply using a marine polyurethane paint, no need to mess with MEK catalyst. Haven't tried that yet.

Valley and SKUK have moved away from hung kayak seats in recent years – which at first I thought was a move simply to save money – cheaper to make one standard seat that can be installed in every kayak model they make. But I now realize the new seats do remedy this fatal flaw – the grinding effect on the hull. The new seats have a wide bottom flange and foam underpad to prevent wear underneath.

Before you go ripping out your own kayak seat – some boats with seats hung/integral to the coaming have enough clearance to prevent the grinding effect. My Valley Pintail had a hung seat with an ocean cockpit that never developed a leak despite being a 14 year-old boat when I sold it. The difference was that it had a substantial clearance (1 or 2 inches) between the bottom of the seat and the hull, and two big pieces of rigid foam beneath.

Aside from the grinding effect, I've enjoyed the hung fiberglass seats on all my kayaks for their form and function – the hip plates and seat are one integrated unit (sometimes integral to the coaming too) making a nice smooth finish that is comfortable, you can slide in and out easily, and the smooth surfaces won’t catch on clothing or tear your drysuit.

Hack-saw to cut out seat

sanding cheek plates to retain backband

The culprit - pit in center of wear area







I'll be replacing the seat with foam initially, but may install Nigel's newer "High Performance Seat" eventually. I've tried his new seats and they are great, more comfortable than most others out there.