|Seacock - courtesy BoatTest.com|
First, an admission of guilt: I am a bit obsessive about seacocks and the movement of water throughout my boat. However, when you consider the penalty for ignoring these systems (sinking) I don't feel too bad about my OCD in this regard!
Let's start with the simple rule: when away from your boat, close your seacocks. That's it. Every time. Toilets, air conditioners, and any other raw water pickups should be twisted closed. It's easy to do, and it could save your boat.
Although some boaters brush this 60-second drill off with a shrug, think of what could happen if one of the multitude of hoses on your boat breaks and starts spewing water into the interior. If the seacock is closed, a little bit of water goes into the bilge, and no one is poorer for the cause. If, however, the seacock is open, your boat is going to learn how to scuba dive in the worst way. And don't for a second think that your puny bilge pumps are going to keep up with an open seacock.
I leave the boat each week feeling much better that a seacock is safe and closed. Of course, even closed seacocks can fail, so be sure to inspect these important dividers frequently for corrosion. We ask a lot of them (protect large holes in our hulls) so treat them with respect.
While we're on the topic of water in your hull, I was asked this weekend why I don't leave my city water hookup on throughout the duration of my weekend stays. Once again: if a hose breaks, an unlimited amount of water from the fine town in which my boat stays will spill into my boat and SINK IT. I rarely use city water anyway, choosing instead to use my freshwater tank in an effort to keep it circulating, and therefore fresh. But if you do use your city water intake, at least turn off the hose at the outlet to minimize the risk of a catastrophic interior tsunami.
Batten down the hatches! A tsunami could happen to you! Right inside your boat...