Looking at a modern sailboat, with its profusion of opening portlights and hatches, you could be excused for thinking all boats are so well ventilated. Not so. Opening portlights are a relatively modern convenience, and as for opening hatches, for many years, well, for many years boatbuilders were more concerned with keeping the elements out than letting air in.
Hence, the many thousands of boats built up until the mid to late 80s were generally underventilated, especially when their hatches were closed at sea or on rainy days in harbor. Our 1973 Norlin 34 was no exception. There was a single opening hatch in the forward cabin, a pair of dorade (cowl) ventilators in the main cabin and a clamshell-type ventilator in the head.
I’m a great fan of dorade ventilators, but they are passive—i.e. the amount of air they admit into the boat is governed by the strength of the breeze. On hot, windless summer days, they are next to useless. The passive clamshell ventilator actually was useless, period. I hate a stuffy boat—leaving aside the unpleasantness of sleeping on an airless boat, stagnant air encourages mildew and mold growth and generally results in the “eau de bilge” aroma present in many older boats. So, one of the first improvements we made to the boat was to fit a pair of Nicro Day & Night 2000 solar-powered ventilators. These store energy in an integral Ni-Cad battery during the day so they can keep working at night, giving you round-the-clock ventilation.
Installation was easy enough. The existing clamshell ventilator’s 3in cutout had to be enlarged to 3 3/4in to accept for new Nicro. Then, after first drilling the screw holes oversize and plugging them with thickened epoxy to prevent water migrating into the cabintop core—all we had to do was apply some caulk and screw the new ventilator in place. That was the heads taken care of.
Because of the way the sail control lines were led aft from the mast there was only one place for the second ventilator—amidships and abaft the mast. We cut out the hole with a jigsaw, and coated the edges of the hole with thickened epoxy. After drilling and filling the holes for the fixing screws, we waited for the epoxy to cure and then screwed the second vent into place.
Each of these vents is claimed to move 600 cubic feet of air per hour; I have no way of testing that, but I can attest to the lack of bilge and other odors on Ostara. We set both vents to exhaust air, since we also have two cowl ventilators to admit air and the boat is kept on a swing mooring, where it mostly facesinto the breeze so that the cowl vents work well; forcing hot air out also keeps the interior fairly cool in the summer heat.
The vents run all year round, even working under the white tarps that cover the boat in the winter.
I suspect that’s why there is scarcely a trace of mildew aboard in the spring—we even store cushions on board in the winter with no ill effects.
After five years of continuous operation, both vents are still working, though one has become quite noisy, so we switch it off when we’re spending the night on board. Generally, though, we’ve hardly noticed the slight whirring sound they make. At around $130 each, these solar-powered ventilators are great investments in liveaboard comfort.