I leave my single seacock open, although I'm only on the Thames in around a fathom.
The pipe from the seacock is in good condition and secure, whats more it ends up above water level, so is the only weak point (i.e. anything else in the system isn't going to have an effect if it fails at berth)
I see no reason a solidly mounted chunk of brass should fail.
(Ice excepted)
-------------------- The scourge of Windsor, and notorious founder member of the 'Upper Thames Birchwood Massive' now outlawed by the EA and River pressure groups, currently planning a nice comfy retirement in the aft cabin of a Broom.
Now can anybody recommend any non-marking slippers?