Last Summer, cruising during the hot season left the admiral less than comfortable. The temperature was sort-of OK when anchored in wind -- it blows through the forward hatch and out the companionway, although mosquitoes flew in, necessitating the wearing of eau d'OFF. When there is no wind or when tied to a pier, air flow isn't so good. I resolved to look for a cheap solution.
Last Autumn, I ran across this item at Lowes on sale for half price -- $20.00.
Now that caught my eye immediately because it was battery powered as well as wall-powered. It looked good! Two speed and off, runs on 8 "D" cells or a wall wart. Even better, it pivoted up and down in its frame. Hmmm ... 12 volts. So I bought it.
I thought about that for a month and realized it was the answer to my complaints, but not in its present form. I wanted something that could pull air in or push air out, and I wanted to pull air through the screened portlights, not via the open hatch -- and i wanted to push air out whenever possible since mosquitoes can't fly upstream.
I, ahem, hatched an idea. Time to brush off the old EE and wood working skills. I came up with this:
It is a double height hatchboard with the fan mounted in it.
First, I needed to disassemble the fan. The frame held in place a useless, light duty single pole, double throw slide switch that had no mounting unless I wanted to redo the circuit board that set up the two speeds. And the frame also held the circuit board in place w/o screws. That will take some thinking. The fan itself turned out better than I hoped. I could leave it in its cage and use the axis and mount as-is! And of course, I could use the wall-wart to convert from 110V A/C to 12V D/C when I was hooked into shore power.
Next, I needed to figure out what parts I would need. I need a box to hold the circuit board and switch to keep them dry, a way to mount the fan on the wood, a way to connect the power to the fan (either 12V directly from the boat's distribution system or 110V wall power via the wall wart), and wiring for the power. I dug through old parts and found a DPDT screw-in toggle switch, it is overkill but I had it already. I also found some old exterior 1/2" plywood lying about the house. I bought the stainless steel nuts, bolts, washers, a typical plastic electrical box and blank plate, a 12 volt male end to fit into my boat's 12 volt outlet, the power jack, both male and female, so I could use the wall wart as-is.
Next came the manufacturing. I cut the plywood to size based on my middle two hatch boards, added some trim I had lying about to fill the edges out to 3/4" as my hatchboards are, then finished it with stain and 3 coats of floor varnish. Then I mounted the fan but oriented the axis vertically instead of horizontally.
I can turn it a full 360 so it can blow in or out. I can aim it anywhere in the salon -- cool the cook, blow toward the settee, or toward the dinette. Only the quarterberth is in its shadow. Mostly, I will have it blowing out and drawing air through the screened portlights -- no bugs!
Here are pics to show how I mounted everything in the electrical box and the two power sources -- 12 V distribution (which at the time did not yet have its power jack) and wall wart. I used a hot glue gun to tack down the circuit board to the side of the plastic electrical box. Wiring was easy. I just had to duplicate what already existed while it was in the old frame.
I had an occasion to try it a couple of weeks ago. It cooled the boat down to ambient temperature in about an hour on high. So here I am the next morning, well-rested and satisfied with my work. I didn't keep strict track of my expenditures, but it was around $50.00.