Project report: See-through drop board with fan, for foul weather.

[DanF]

Hi all,

I gained a great deal of knowledge from this board during the first couple years we owned our CP23, so I just wanted to give back a bit in the form of a project report others might like to duplicate.  Our old Cape Dory 30 had a spare bottom drop board with a 12V exhaust fan built into it, which was marvelous when on a cruise and stuck at anchor for a couple days in rain or fog (as so often happens here in Maine.)  I decided to replicate this for the CP23, with the upgrade of making the board of transparent acrylic to reduce some of the claustrophobia of being stuck in the cabin.  (I'm sure I'm not the first person to have thought of or done this, so apologies if it seems I'm plagiarizing someone else's idea...)

The board is 3/8" acrylic, cut in a trapezoid to match the stock bottom board, with a 3" round hole in the center.  Dimensions: Top edge 28.75", bottom edge 26.5", side edges 11.25" (height, top to bottom, 11.19").  I purchased a piece cut to exact size from fabglassandmirror.com.  On their website, if you click the "Plexi & Acrylic Glass" tab at the top and it will quickly walk you through the ordering, including the option to add a 3" hole.  Cost was about $110.  Of course you could just buy a stock piece of 3/8 acrylic and shape it yourself, but the extra cost was worth it to me to have that done professionally.

The only thing Fab Glass didn't have as an option was beveling the top edge to match the bevel in the top board, essential in my opinion for keeping rain out.  So I did that myself with a 45 degree chamfer bit in a hand router.  It was pretty easy.

The ventilation component consists of a Vetus "Electric Ventilator" (model #F12), which mounts to the inside of board, and a Vetus  "UFO Deck Vent with Transluscent Top" (model UFOTR) which mounts to the outside.  I bought these from Defender for total of about $150.  The "deck vent" may not be entirely necessary-- the board from our Cape Dory just had the fan blowing straight out an open hole, and so long as you kept it running when it was raining water didn't intrude.  But you might particularly want the vent cover if you ever envision sitting in the rain at a dock rather than anchor or mooring, where the rain might be blowing at you from behind.

The last component was just a 12V plug with bare wires.  I had one lying around but you can easily buy one from Amazon etc.

Mounting the fan & vent to the board was the only challenging part of the project.  I would not attempt it without a drill press.   I used #6 pan head stainless sheetmetal screws all around-- 1/2" for the fan and plastic portion of the vent, and 3/8" for the metal part of the vent.  You'll want to view some internet advice on how to drill acrylic; I followed a YouTube suggestion to file down the "wings" of a drill bit to make it pointy and that worked well.  The holes are so small that I think the likelihood of cracking the acrylic is low.  To install the screws, I used another YouTube suggestion of heating them with a propane torch (holding them with mini vice grips) so that they would be hot going in and melt their own threading into the plastic.  Again, worked great.

The final product just drops in like the stock board, then plugs in to the "lighter socket" below the companionway.  I need to get a "splitter" for the socket so we can still plug in our phone charger etc. as needed.  The fan uses only 0.2A so no worry about overloading the circuit.  When not in use we keep it in an old pillowcase to prevent scratches.

Of course, having spent the time and money to build this last spring, we wound up having near-record drought here this summer  and only needed to use it once!  But that won't last forever.  Hope this write-up will be of use to someone!

PS.  I did have a couple problems with the Vetus items.  First fan I received wouldn't run no matter what I did with it-- contacted Defender and was promptly sent a replacement.  With the vent, I could not seem to get the metal piece low enough on the plastic piece to sit flush with the board.  Finally I realized all I had to do was sand down the little plastic feet/pillars on the plastic bit by a mm or two and that solved the problem.

[Cruzin]

Nice job!

Dale

[HeaveToo]

I hated having to close the cabin.  My 23 had a dodger, bimini, and an connector.  Even better was the rain hatch umbrella that I used for the front hatch.