New Solar Vents

In this March 2011 project I am replacing the three old cabin vents with new solar powered vents
West Marine sells these vents:
NICRO Ventilation Day/Night Plus Solar Vents #N20704W
The 4″ vents were used and required making the existing holes a little larger.

Type: Solar/battery-powered vent Material: Stainless steel or plastic Draw: No external power (NiMH battery/solar cell) Warranty: Two years

Solar-powered ventilation 24/7

The improved design of Day/Night Plus Vents moves up to 1000 cubic feet per hour, freshening your cabin 24/7 by running on solar power during the day, while charging a small battery to run at night. The constant flow of air produced by these vents helps to keep boat interiors dry which extends the life of upholstery, electronics and metal components. Vents easily retrofit to existing 3″ or 4″ Nicro vent cutouts. Direct-to-deck mounting affords greater security and protection against theft. Each includes an insect screen, below-decks shut off damper and internal on/off switch. Two blades (exhaust and intake) are provided with each vent. Install a pair of these to create efficient cross ventilation.
underOldVent This image shows what was under the original stainless outside vent cover.  The geen tint of the photo is the result of the tarp I use to keep the sun away.  As you can see the original plastic part of the vent was disentigrating away.  Lots of caulk was used also.  The vent in the head had leaked and over time rotted some of the balsa core.
afterCleanupAndEpoxy  
This image shows the hole after cleaning up the mess. Here I have lightly grinded the surface and filled in the screw holes with epoxy and filler.  You can see the balsa core also.  I used my dremel with a barrel cutter to remove about 3/8″ of the balsa core.  I then made up a batch of epoxy with filler to apply in place of the removed balsa.  This seals the cutout to prevent any chance of water getting into the core.  I had to cut the hole a little bigger to install the new vent.
catchBag Here you can see the “Catch Bag” I duct taped to the cabin ceiling to keep the cabin clean of all the removed balsa and fiberglass.
coreViewInside Here is a close up view looking from the inside out.  You can see the upper 1/4″ or so upper and lower layers of fiberglass with the 3/4″ balsa core material.  The cabin roof is actually a totally seperate layer of 1/8″ or so fiber glass.  The space between the actual cabin top and the inside cabin liner veries from 0″ to 1″ or so.
ductTapeEpoxy Here I have applied duct tape to keep the thickend epoxy from dripping into the cabin.
innerRing Here you can see the new inner vent ring in place.  This if looking at it from the outside.
newVentInside This photo shows the vent ring in the last photo, from the insde.  It is screwed to the cabin roof and the vent fits inside the ring.
newVentOutside Here you can see the new vent from the outside.  I used poly butel tape to seal between the vent and cabin top.  Wind Dragon has 3 of these vents, one in the head, one in the galley and one in the solon.