Builders' Forum Archives
Re: what if...God forbid!
Posted by Laszlo on Sep 16, 2007
I certainly do believe in pressure cycles and fatigue failure - I just haven't seen evidence of it occurring in my boats.
Commercial jetliners are typically pressurized to 5,000 feet alitude and flown up to 35,000 feet, possibly several times a day. That's a much greater differential (about 9 psi) than what we see in our boats with many more frequent cycles, so the analogy is not really applicable.
A kayak accident which is catastrophic enough to puncture the hull changes the rules, i.e., it is no longer a sealed chamber so that discussion is moot.
As for sitting in the sun and then plopping it into cold water, maybe I've been lucky in when I glued the compartments shut. In both cases it's been early in the morning when the air was cold. Boating season cold water temperatures are pretty close to the air temperatures of when I sealed the air in, so maybe that's why I've gotten away with it.
Finally, the pressure differential is closer to 1 psi than 2, and that's over a 30 degree Celsius range, so it's not as extreme as all that.
Anyway, if people want to put in drains, that's fine. I was just offering the observation that I didn't and I haven't seen any problems over the space of years.
Have fun all,
In Response to: what if...God forbid! by theo on Sep 16, 2007