The Key to Long-term Structural Health and Livability for Any Boat is Great Ventilation
June 08, 2006 Comments
The key to long-term structural health and livability for any boat is great ventilation. The ventilation system must be versatile so that the amount of fresh air flowing through the boat can be adjusted to suit conditions. It is also important to be able to have some fresh air supply even in the worst conditions.
Normally air flow through a boat is from forward to aft, thus there should be a thread-in Dorade or a mushroom vent as far forward as possible. The Dorade is better because it will funnel more air down into the boat, and it can be replaced with a flush plug while sailing.
Next important is one or two cowl or Dorade type vents just forward of the transom. These should be pointed aft and act as exhaust vents to pull stale air out of the boat. Ideally these would be fitted with small, low powered fans to achieve positive air movement.
Important to the success of bow and stern vents is the possibility of air moving freely through the boat from the inlet forward to outlets aft. It must be possible to leave the boat with all interior doors open.
In addition to the fore and aft vents will be supplemental ventilation along the way. Usually this will take the form of hatches, there should be at least one in each compartment, additional Dorade type vents used when the boat is locked up, and extractor vents used in areas like heads and the galley.
To work well hatches (Dorades as well) must be high up. I prefer them off the deck on a trunk or cabin. Flush hatches funnel water below decks and low combings just stub toes. The higher a hatch is the longer it can be left open. The very best is if the hatch can be opened forward (when anchored) or aft, (when sailing).
Sliding hatches should have a series of drop boards to adjust the amount of ventilation provided. Any and all vents should have positive, watertight, closures. Also all openings need screens fitted at times.
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