I got pressure relief valves in my new one because the Humber tubes used to get rock solid in direct sunlight with black wear patches on them. The PRV's blow off on a sunny day, even in our temps here, so they are well worth having. I've never heard them go, but if you get hot weather > cold weather the tubes are usually soft.
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...
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