Roger Long wrote:
Drains above the waterline are also much less prone to clogging. The
floating stuff goes right through instead of building up into a mat at
the water level.

That's a nice feature of a catamaran! The cockpit is several feet
above the water.


You should close the seacocks on below water hoses when leaving the
boat so that means coming back to water (and slime if its been a long
time) in the cockpit.

That sounds like prudent advice, but I seem to remember that the
largest single cause of boats sinking is clogged cockpit drains.