If you own a boat with enclosed spaces or an open boat that’s covered when not in use, you should be familiar with the Nicro line of ventilation products. Nicro has been producing both active (powered) and passive (redirects air movement) ventilation for more than 30 years.
A product I recently added to my boat is the Day/Night Plus vent, which has been improved and moves up to 1,000 cubic feet per hour (24,000 cubic feet per day), providing continuous fresh air to your boat’s interior. The Day/Night Plus is totally self-contained, requiring no outside source of electricity, and it can be installed through almost any hatch or deck surface where there is a reasonably flat surface. It may seem obvious, but be sure the selected location doesn’t pass through electrical wiring, plumbing or other obstructions.
The Day/Night Plus provides 24-hour operation by using an integrated nickel-metal hydride (NiMH) battery and a photovoltaic solar array. The solar array powers the unit’s fan during daylight hours and provides charging to the NiMH battery, which in turn powers the fan during hours of darkness. The product literature indicates that the fully charged NiMH battery will operate the vent for up to 40 hours.
The battery’s life span is typically between two and three years, while the photovoltaic array should last 20-plus years, according to David Colclough, from Nicro technical support. When the time comes, a replacement battery is available either directly from Nicro or through Radio Shack.
I checked the fan speed while it was operating in daylight and charging the solar cell. The fan was turning 122 rpm. I covered the solar array for 24 hours and left the fan running on battery power, with a resulting drop in fan speed of only 4 rpm. Like all active Nicro vents, the Day/Night Plus includes interchangeable fan blades to provide either intake or exhaust air.
The Day/Night Plus is designed to fit directly on the hatch or deck surface and mounts on its own base plate, which must be installed correctly to ensure proper operation and watertight integrity. If the deck surface is cambered, be certain there is no more than a half-inch of curve over a 12-inch length of deck surface. (Place a 12-inch straight edge on the deck location and rock it, then rotate it 90 degrees and repeat.) For deck camber greater than a half-inch, a compensating shim will need to be installed.
The installation of all Nicro vents requires only basic hand tools and either a sabre saw or drill with a large hole saw. (A jigsaw will likely be more convenient for most boaters.) Since the vent operates on both solar and battery power, there are no electrical cables to run, simplifying the installation.
I have previous experience with other Nicro products and, being confident in their quality and design, I had no hesitation in cutting a hole in my solid teak aft cabin hatch. I was installing the 4-inch-diameter vent, which required a 4-3/4-inch hole. I marked the center of the hatch and cut out the required hole using a hole saw. If you use a sabre saw, I recommend covering the deck area with wide masking tape to prevent the saw base from marking the deck. (You also can apply the tape directly to the saw base.) Use a compass to mark the diameter of the hole and carefully cut along the line. Regardless of the method you choose for cutting, clean up the edges of the hole with sandpaper or a file.
There are several choices for finishing the portion of the vent in the boat’s interior. Nicro offers trim rings of plastic and teak; soft, protective rings for hatch installations; and snap-in screens. The vent exterior is offered in white and stainless steel.
Begin the installation by mounting the selected trim ring from the interior. Back on deck, fit the base plate into the hole to confirm alignment. Mark the three mounting holes. Remove the base plate and drill the mounting holes, being careful not to drill through to the interior of the boat. Rough up the mounting surface and the bottom of the base plate to promote good sealant adhesion; 100-grit sandpaper works well.
Apply a quarter-inch bead of silicone sealant to the underside of the base plate and to the surface where it will sit. Slide the base gasket over the base plate (optional for hatch installation), align the fastener holes, and set the assembly onto the deck. Place the cover — which includes the fan motor and blade — battery and solar array over the base and carefully install the final screws. Be sure not to squeeze out the sealant or distort the base plate by overtightening.
The new Nicro Day/Night Plus includes an on/off switch inside the fan housing. To access the switch, gently place a finger on the fan hub until the blade stops turning, then press the rubber-covered switch. Shutting off the fan enables you to operate the green water shut-off damper. There are two ears on the inside edge of the fan housing. Pushing the ears up moves the damper about a half-inch up, where it seals on the vent cover; pulling the ears down allows air to flow through the vent.
I installed the Day/Night Plus in early April, and by late June I hadn’t seen any water intrusion either from heavy storms or my heavy-handed deck washing. When installed according to the excellent guide provided with the unit, the vent provides good watertight integrity and enhances vessel ventilation. There was a substantial improvement in interior air flow on my trawler, as evidenced by the lower interior temperature and lack of “closed boat aroma” following the boat being locked up for a week.
Don’t be misled if you place your hand at the vent location and don’t feel rapid air movement. These units aren’t designed to create a wind tunnel. They slowly move volumes of air that may be imperceptible — and they work very well. I had two older Nicro vents on my previous boat, and they worked continuously in the five years I owned her. One was in the forward hatch as air intake, and the second was in the head as exhaust. Being installed on a sportfisherman, these units saw much more seawater over the deck than my Day/Night Plus will, but there was never a water intrusion issue.
Nicro provides plenty of technical information on its Web site regarding application, sizing and quantity of vents recommended, which is based on vessel configuration and size. Ventilation on board is certainly one place where more is better. The products work well and last in the marine environment.
The 4-inch Nicro Day/Night Plus retails for around $160 and is available from most major chandleries. For information, contact Marinco Electrical Group, Napa, Calif., at (707) 226-9600, or visit www.marinco.com.
This article originally appeared in the October 2008 issue.