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Would welcome thoughts of members on the subject of ventilation. I was about to replace the 2 plastic mushroom vents with new mushroom vents. Before it is too late I would be keen to hear what others have found best. Interestingly saw a boat the other day with 2 Ventilators (static) and it had one facing forward and one facing aft. Best of both worlds? Which ventilators did you find to be waterproof?

Cheers

I have 2 mushrooms facing aft. I find them insufficient in that mould grows within 2 weeks on all the unlined fibreglass interior even though I have cleaned with bleach or vinegar. I also leave the front hatch slightly open & the cabin entrance wide open to maintain fresh air flow.

I have two mushroom vents facing aft.
A vent in the washboards.
And a solar exhaust fan above where I sleep in the V berth.

Works beautifully.

Sea Lady has not had any mould at all since her refit.


Prior to the refit she was leaking water through a number of places, windows and the anchor well being the worst offenders.
I was not aware of these leaks, my shipwright found them and rectified them.

Most boats tend to have air movement in from the washboards/companionway, and out from the bow area if the vents face aft. Hence Diana's system is very effective. You can reverse the flow, but that usually means a large air scoop at the forward hatch. (At anchor.) Front opening hatch does that too, but the danger is, if it comes open accidentally, it can scoop in the sea. Front hinge is safer.

I have a 100mm computer fan that blows out through a stern-facing vent in the forehatch. This keeps the condensation and mould at bay since I fixed the deck leaks. It only consumes about 100mA (2.4 Ah per 24 hours) which the 60W solar panel easily keeps up with, even through the Melbourne winter.

Cheers, Graeme

Ianb wrote: Front opening hatch does that too, but the danger is, if it comes open accidentally, it can scoop in the sea. Front hinge is safer.

Top Hats were built with the hatch front opening, unless change by owners.