Question: The photo I sent in is of a small fan located in my V-berth area in a small compartment that has some other electrical equipment in it and a small battery charger.

This fan ventilates the bow storage area when the battery charger for the bow-thruster is running.

This fan ventilates the bow storage area when the battery charger for the bow-thruster is running.

There is a hole cut in the panel it's mounted on that creates a vent access to the very bow of my boat where the battery and bow thruster are located. It seems like the fan runs whenever the small battery charger is in operation. This is kind of a problem because I can hear the fan running when I’m trying to sleep in the V-berth, and it's annoying. What’s the trick to fix this fan so that it isn’t running when I’m trying to sleep?

Answer: Fans like this are increasingly used to force ventilation through restricted areas on board modern boats. They are used to make sure there is no danger of a build-up of potentially explosive hydrogen gas in battery storage areas during charging, and/or to help keep electronic equipment from running too hot during normal operation -- in your case the battery charger you mention.

You don’t tell me whether there is a master switch on your main AC (shore power) panel board for the charger. If there is, then your problem is easily solved by simply making sure the switch is turned off while you're trying to sleep. You can always turn it on during evening meals or after you get up in the morning. Truth is, it really doesn’t take too long to recharge a bow thruster battery that is used intermittently, so leaving the charger on for extended periods is not such a great idea anyhow.

If there is no master switch on your main AC panel board for the charger, I recommend you add one. If this is something that you aren’t comfortable doing, it is really not a very difficult task for a marine electrician to retrofit. To make it even easier, you could install the switch in your V-berth area so you can turn the charger/fan combination off right from your bunk when you're trying to get some shut-eye.