Ventilation and Air Flow

For anyone cruising that lovely band of the planet earth know simply as “the tropics,” the subject of keeping cool while trying to chill out is near and dear to the heart.

We’re fortunate to own a yacht which had been designed with good air flow and ventilation as a high priority. Our hatches and port lights are large and many, and with eleven dorade vents, every interior area has ventilation, even when we’re under way and the hatches are dogged. Eight interior fans keep air moving when the apparent wind goes away.

At anchor, we generally lie to the breeze, if there is any, and keeping some or all the hatches and port lights open will usually keep us comfortable in moderate tropical weather conditions, when we’re not too physically active, or the oven isn’t on for long periods of time. In many cases, there is less air circulation in a marina environment, so in some cases we may need to resort to aircon, especially in places like Singapore or summer in Australia, where the daytime temperatures exceed the mid 30’s Celsius/90’s Fahrenheit.

When we are underway, or it is raining, we must be more diligent about keeping the wet stuff on the outside of the boat, while still attempting to keep some airflow inside. On passage we have storm covers that protect all the hatches forward of the center cockpit. They are designed with zip-up side gussets that allow the hatches to be opened if conditions allow. All our hatches open facing aft, so even if there is the odd bit of spray or light rain, we can generally keep hatches open a bit as long as we’re not shipping green water. Our dinghy is stowed upside-down on the foredeck when we’re on passage or in a marina, so we can open the master stateroom hatch underneath even in a downpour, provided there’s not a strong cross breeze. This really helps keep us comfortable when we’re sleeping. Otherwise, a fan on low speed does the trick

On deck, we have a dodger/spray cover that easily covers four to six people, depending on sun angle. When we’re at anchor, we put up a bimini top over the aft cockpit and have a zip in awning between the dodger and bimini. The combination of the three shade nearly half the boat, and allow all the port lights and four aft hatches to remain open, even in a bit of rain.

Over the years, we’ve tried a number of fans, and our all time favorite is the Hella Turbo Fan, which is generally available world wide. It provides a good amount of air flow for the current draw and is very quiet. The white color blends into the décor (see photo). The only bad news is that it is more difficult to clean than some other models. The Cafrano is our second choice because it provides good air flow and is easy to clean. The bad news is that it is slightly noisier than the Hella, and has no guard so it is possible to get hair tangled in, or body parts nicked by the blades.

Aside from aircon, the Dorade vent has to be one of the greatest comfort inventions for boats since the mattress. To get the right air flow, one must experiment with aiming them in different wind conditions, because each boat’s airflow patterns are different. Otherwise, I would offer two pieces of advice if you happen to have Dorades that have the soft PVC cowls. First, I attach all of mine to the mounting ring with steel trace line used for fishing leaders (see photo). That way they stay on board if someone inadvertently knocks one off or it gets popped off by a sheet or other line. They also have a tendency to develop a very ugly brown sunburn due to UV exposure, so I have had mine all painted with linear polyurethane paint. In six years, all I’ve had to do is give them an occasional going over with a cleaner/wax combination and they still look pretty good. 

For those hot days on deck, we keep a fine mist spray bottle on deck full of water. An occasional misting of the body will help to cool you off between dips in the ocean.

Stay cool!

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