Dick Locke wrote in
:

Two of them had extensive damage and nearly
sank at the dock before anyone noticed the problem.

It is SO easy to install a REALLY LOUD Radio Shack alarm siren (plastic
horn up on the mast) running off a bilge pump float switch 6" higher than
the one that runs the bilge pump that should NEVER float unless we're
losing the battle with the leak......to make sure NOONE in the marina
sleeps until your boat is PUMPED OUT or you're notified.

Lionheart's 'il WAKE THE DEAD!

The only way to cut ours off is to take out the fuse at the house battery
terminal....(c; No, you can't disconnect it and go back to bed as the boat
sinks! Notice the big strobe light UNDER the siren horn to help you get
their faster.

The horn is also connected to the FIRE ALARM sensors (3), too!

Does YOUR boat have a flooding/fire alarm installed?.....