If you own a boat with enclosed spaces or an open vessel that’s covered when not in use, you’ll want reliable ventilation. For more than 30 years Nicro has produced both powered (active) and passive vents designed specifically for marine use. One recent addition to my boat is the Nicro Day/Night Plus, a solar-assisted, self-contained vent that delivers continuous fresh air to a cabin or enclosed locker.
The Day/Night Plus has been upgraded to move up to 1,000 cubic feet per hour (about 24,000 cubic feet per day), providing steady ventilation without relying on the boat’s electrical system. It installs through most hatches or deck surfaces that offer a reasonably flat area. Before cutting, verify the chosen location is free of wiring, plumbing or other obstructions.
The unit combines a photovoltaic solar array with an integrated nickel-metal hydride (NiMH) battery to achieve 24-hour operation. During daylight the solar panels power the fan and charge the NiMH battery; at night the battery runs the fan. According to Nicro’s literature, a fully charged battery can keep the vent operating for up to 40 hours. Typical battery life is two to three years, while the solar array should last two decades or more. Replacement batteries are available through Nicro and common electronics suppliers.
In daylight testing I observed the fan turning at roughly 122 rpm while charging. After covering the solar array for 24 hours and running on battery alone, the speed dropped only slightly—about 4 rpm—demonstrating consistent performance. Like other Nicro active vents, the Day/Night Plus includes interchangeable fan blades so it can be configured as intake or exhaust depending on your ventilation plan.
Installation is straightforward and requires only basic hand tools plus a sabre saw, jigsaw or a drill with a large hole saw. Because the vent is solar- and battery-powered, there are no electrical runs to make, which greatly simplifies fitting. The vent mounts on a base plate that must be installed correctly to ensure watertight integrity. If your deck is cambered, check that the curve does not exceed 1/2 inch over a 12-inch straight edge; if it does, a shim is needed to ensure a proper seal.
When I fitted the 4-inch model into a solid teak aft cabin hatch I used a 4-3/4-inch hole. If using a sabre saw, protect the deck with wide masking tape to avoid marking the surface. Mark the hole precisely with a compass and cut carefully, then clean the edges with sandpaper or a file. Nicro offers a selection of interior trim rings in plastic or teak, soft protective rings for hatch installations, and snap-in screens. Exterior finishes come in white or stainless steel.
Begin the install by fitting the chosen interior trim ring, then test-fit the base plate from the deck to confirm alignment. Mark and drill the three mounting holes, taking care not to penetrate into the cabin. Scuff the mating surfaces with 100-grit sandpaper to improve sealant adhesion. Apply a quarter-inch bead of silicone sealant to the underside of the base plate and to the deck surface, slide the optional base gasket over the plate if using one, align the fasteners and set the assembly in place. Set the cover—containing the fan motor, blade, battery and solar array—onto the base and secure the final screws without over-tightening; squeezing out sealant or distorting the base plate will compromise the seal.
The Day/Night Plus includes an internal on/off switch covered in rubber. To access it, stop the blade with a gentle fingertip press on the fan hub, then press the switch. Turning the fan off also allows operation of the green water shut-off damper: two ears on the fan housing move the damper up to seal on the vent cover or down to permit airflow.
Since installing the unit in early April I have not experienced any water intrusion, despite heavy storms and thorough deck washing. Installed according to the manufacturer’s instructions, the vent maintains watertight integrity while considerably improving interior airflow. On my trawler the cabin temperature dropped and the “closed boat” smell disappeared after only a week of being locked up.
Don’t be discouraged if you don’t feel a strong breeze at the vent—these fans are designed to move large volumes of air slowly rather than create a wind tunnel. In practical use they maintain fresh air circulation very effectively. I previously owned two older Nicro vents that ran continuously for five years on a sportfisherman, handling much heavier deck exposure without any water intrusion.
Nicro publishes detailed guidance on selecting, sizing and placing vents based on vessel layout and size; generally, more ventilation is better. The Day/Night Plus is a durable, low-maintenance option for marine ventilation in cabins, lockers and other enclosed spaces.
The 4-inch Nicro Day/Night Plus typically retails for around $160 and is stocked by most major chandleries. For assistance, contact Marinco Electrical Group, Napa, Calif., at (707) 226-9600.
This article originally appeared in the October 2008 issue.