I understand that breather tubes are necessary for SUPs to prevent pressure from building up (or down) inside the enclosed space of the board. Do the bulkheads on the Oxford II shell not also create airtight compartments that could create a similar problem?
hi seth,
in general, the enclosed spaces on a kayak or shell shell should have a planned way to allow pressure to equalize between the outside and the inside. Without it, the space can become pressurized or have a vacuum develop which can deform the hull.
Equalization can be acheived through a hatch which does not form a perfect seal, or a small breather hole in the middle of the bulkhead. the middle of the bulkhead is chosen such that if the boat were rolled or otherwise took on water, the hole would be above the waterline you would expect with the floatation tanks whether the boat is right side up or rolled…..(Note: some hatches are designed for a reliable perfect seal - so you may want to consider a pressure equalization hole even with a hatch)
in my kayaks that have a need for it, i drill a 3/16 hole into the middle of the wooden bulkhead, fill it with epoxy and then drill a final 1/16 hole through the epoxy using the drill, fill, drill method.
you tend to notice the problem of pressure imbalance more on SUP’s because of their large flat decks and the percent of hull in the water. the SUP can be on land, in the hot air, and when put it in the cool water, quickly cooled, reducing the pressure rapidly. And it does not take much of a pressure differential on a SUP to deflect the hull shape because flat surfaces deflect much easier than curved surfaces.
smaller, narrower and curved decks are much more resistent to deflection due pressure changes.
a certain pressure differential can be accomodated based on the strength/shape of the structure….(in other words pressure differential does not always equal noticable hull deflection) so in certain case, i suspect, folks don’t pay attention to this becuase its not a problem they observe.
fwiw, it used to be part of the instructions, to put a breather hole in the bulkheads, in building a CLC 17 Chesapeake and several other kayaks kits CLC sells.
i hope this was helpful.
h
Yes indeed. I suspect it’s the dimensions of the Oxford II (narrow, long, bowed deck) that preclude it from needing a vent.
Thank you.
I too was concerned about the 10 sealed compartments on my Rhode Runner build. I just couldn’t stand the idea of just hoping that all would be good forever, without an ability to know what was going on inside there.
My solution is to use breathable watertight vents made by Amphenol. They are normally used in electrical enclosures and light fixtures to allow pressure venting. They have a Gortex- like membrane that block liquids. I got them for about $2 ea.
They make them in many different specs, but the ones I chose are plastic bodied, water rated, and screw into a 12MM threaded hole. My thinking is that in the future I can look in there with an endoscope, and if anything looked funky, could also insert a vacuum line or an air line.
Any think this is a bad idea or not needed?
I like that better than a wine cork and straw!.