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Installing A Cabin Fan


Installing a new fan is a pretty easy project. In fact — it’s a breeze!

A little breeze, blowing across a bunk on a boat at night. A breeze on your face under a heat-absorbing windshield. Truth be told, any breeze at all makes things more tolerable on a boat when it’s hot, and modern 12-volt fans draw almost no current while bestowing the magic of cool. We had a mess in the aft stateroom of Chez Nous. There had once been a long-extinct dinosaur of a fan hanging from the overhead. My job now was to clean up the mess left by a previous owner and install a modern replacement.

This is an easy task consisting of little more than finding the optimum position for the fan before mounting it neatly in position. The hardest part is running the cables so they remain out of sight. I was lucky because these were already in position, but if you’re doing a similar project on your boat, you may have to run your cables back to the breaker panel, and this can often be the longest part of the job to complete neatly.

First came the wiring. On an older boat, one constantly checks and replaces wires as a matter of course in almost every job. Every new installation provides a new opportunity to improve, replace, and update. The old fan wire on my boat was suspect, not to mention unsightly, and the situation was made worse by a tear in the overhead left by the previous owner. The amperage capacity of the existing wiring was more than adequate for the new low-amperage Caframo fan we planned to install, but that wasn’t the whole story. I spent some time checking not just the cables to the fan but also other cables lying close by, tracing their sources and checking voltage loss that would show bad connections and/or bad wiring upstream.

Technical Support

Degree Of Difficulty: Easy to moderate


  • Wire strippers
  • Wire cutters
  • Crimpers
  • Flashlight and/or headlamp
  • Screwdrivers
  • Digital multimeter

Cost: Estimate $85 for the fan and $20 for a partial sheet of high-density polyethylene

1. Checking the wiring took a while because it’s important to understand where the wire runs and to remove anything that isn’t up to snuff.
 The task is made easier with good lighting (I use a headlight and scene light for such jobs), and I use of a digital multimeter to check cables for continuity and voltage drop. I found that the wire left behind from the previous fan was good near its source but not so good near the end; the circuit itself was protected by properly sized circuit breakers.

2. I removed the bad cable with wire cutters, then stripped back the ends of the cable, taking care to use the connections as a stripping guide, and crimped in replacement cables using butt-end connectors to join the new cables to the old.

3. Next, I turned to the job of covering the mess in the headliner with a good mounting for the fan and some “beautification” for the headliner. I purchased a sheet of West Marine’s Marine Lumber, a UV-stabilized, saltwater-resistant high-density polyethylene. It’s very easy to cut material such as this with a circular saw. I cut it long and wide enough to cover a tear in my lining, to extend to the battens behind the lining (for mounting), and to position my fan. Drilling screw holes through the Marine Lumber was easy — except for the measuring, where I always screw up, down, and every other direction.

4. Planning ahead, I also drilled a hole behind the fan and ran the wire through, temporarily positioning the board in place. Screwing the board into the battens was easy, as was mounting the fan. Although these fans are articulating and adjust vertically, it’s still important to position them to get the maximum benefit and to avoid obstructions.

5. Done deal! We now have adjustable breeze with almost no current draw, a nice background noise to lull me to sleep when it’s flat calm, and a much prettier aft cabin.

Tom Neale

Technical Editor, BoatUS Magazine