Travels with Paddles

a sea kayaking journal

Axel Schoevers (Photo: A. de Krook) Name:
Axel Schoevers
Rijswijk, Zuid-Holland, Netherlands

Thursday, June 19, 2008

Under Pressure

Sometimes it feels that I am on a crusade. Although most of my gear is in waterproof containers or bags, I just hate paddling a kayak that leaks. Worst are the poly-ethylene kayaks; very few of those actually are and remain dry, so it is not impossible! Glass-fiber sea kayaks with round rubber hatch-covers and glass-fiber bulkheads should NOT leak, PERIOD! And IF they leak (poor quality control or by damage or wear) they can be (again) made bone-dry. I found the round rubber hatch-covers the only ones I can truly trust on every pressure or vacuum.

I used to borrow pressure hatches, but this week I made my own. Tubeless car-tire valves bonded to the hatch-covers with SikaFlex.

Having been in and around bone-dry kayaks for a while now, I have now found another issue that needs sorting. The pressure build-up can be so great because of temperature differences (i.e. warm air / cold water or hot sun / car rooftop), that this can produce cracks in the gel-coat or 'awaken' any other weak-spot, a new leak. Any kayak has a zillion 'weak-spots', it is just a matter of time before the stronger weakness shows up. I drill 1 mm holes high in the center of each bulkhead, and tape them shut when I need another pressure test. Yep!, if my cockpit is full of water for a long time, my hatches will take in water drop-by-drop. Yep!, I swim a lot, but generally only for a very short time...

Oh, forgot to tell... How to find the leak with the pressure hatch-covers? Just as finding a gas leak, brushing suspected areas with washing-up liquid. And when you find the leak? Just read Ocean Paddler Magazine for expert advice on how to work glass-fiber repairs.


David said...

Gidday Axel,
'Agree wholeheartedly with your comments about 'glass boats being leakproof. Drybags for your gear should be more for unpacking and setting up camp in the rain rather than keeping gear dry in leaky compartments!
Re pressure relief valves for the hatches, I now use small spray/screw irrigation fittings that are sold for garden watering systems. They fit through the bulkheads and seal up well with sikaflex. (What did we ever do without this stuff?)
I keep them cracked open a fraction most of the time and screw them shut for re-enter and rolling practice. They look professional and work flawlessly. 'Can send pics if you like.

Axel said...

Hi David,
I would indeed like to see a picture of the irrigation fittings. So that I know what to look for in the local garden centres. Maybe there are different types. SikaFlex is messy stuff, but sure works. But any secure bonding between plastics (ABS) and glass-fiber requires Sika-Primer. Hatch-rims do come off when you cleaned them with Acetone after sanding them, I can tell from personal experience! Sika-Primer can be bought in conveniant 30 ml cans.