How do you keep your boat cooler without AC?

[captainwireman]

Blistering sunlight and high humidity make for an uncomfortable situation. Fans make a huge difference. Any other thoughts on this subject?

[Copacabana]

Yes.
1) Paint all horizontal (and vertical) surfaces white (even an off-white deck heats up horribly under the sun).
2) Use awnings during the day to keep the sun off the whole deck.
3) Improve ventilation aboard (more opening hatches, wind scoops etc.)
4) Have a way to keep everything open when it rains without water getting in.
5) Fans can help to move air, but they are a last resort.

[Cheechako]

A tarp or cover well above the cabin keeps heat out a lot. the sun doesn't bake the boat surfaces that way. Can be a pain when It gets windy, but a well designed custom one, just covering the cabin length is great.

[Kelkara]

Go North!

[Bill O]

Originally Posted by Copacabana

Yes.
1) Paint all horizontal (and vertical) surfaces white (even an off-white deck heats up horribly under the sun).
2) Use awnings during the day to keep the sun off the whole deck.
3) Improve ventilation aboard (more opening hatches, wind scoops etc.)
4) Have a way to keep everything open when it rains without water getting in.
5) Fans can help to move air, but they are a last resort.

Agree with all the these recommendations, especially the white deck surface. It passes the "barefoot test" on our boat, even on the hottest days.

Additionally, if you have room, add insulation inside between the deck and headliner. This is helpful if you are underway and can't have the awnings up.

A tall 4-way wind scoop helps get a decent amount of air in the boat even in light air and is less fuss than a regular air scoop if the boat is not directly pointed into the wind.

Also can't over emphasize the importance of good ventilation during bad weather. Dorades help but hatches are still the best for good air flow. We have storm dodgers over the forward and aft hatches and they really pump a lot of air down/through the boat. The forward storm dodger is good until about 45 kts, then the windage is a little too much.

So far we have no need or plans to install an AC system, as long as we are out at anchor, we get plenty of air flow through the boat.

Cheers,
Bill O.

[StuM]

Originally Posted by Kelkara

Go North!

That doesn't work in half the world

[Calif.Ted]

Originally Posted by StuM

That doesn't work in half the world

Stay between 30 and 35 degrees ? Not too hot, not too cold ?

[StuM]

Originally Posted by Calif.Ted

Stay between 30 and 35 degrees ? Not too hot, not too cold ?

I prefer to stay between -25° and +25° I'll take hot over cold any day

[StuM]

I agree with the others who talk about air flow. Plenty of hatches fore and aft that open in the appropriate direction and air scoops make life on board in the tropics tolerable in even light winds.

[Olly75]

Wet the decks down, evaporatitve cooling is a powerful thing.

[JPA Cate]

G'day capt.wireman,

One thing Jim did on our previous boat was to mount a computer fan so that it sucked the outside air down, right at the forward end of the v-berth, so cooler night air could then be blown by the fan over both of us as we lay asleep. The hottest two places we've had to sleep were the Golfo de California (Sea of Cortez) in the summer, and the Solomon Is, at about 6 deg. south of the equator. We have never used air conditioning, other than awnings, windscoops, and fans. I am well committed to fans, however, and do believe them to be necessary for places that feel "too hot" to me.

We also have painted our decks white, the non-skid (larger area) being the whiter white, the topsides and deck and house are a greyish white.

I made one of the all-way type of reefing windscoops for our first Insatiable, but for this boat, we made a hatch dodger for the forehatch, which works well for leaving the hatch open in the rain. It also shades the hatch, so by its nature, shades the place on the foredeck that would otherwise heat the boat. Another factor for me is that it does not take up so much room on the foredeck as our old one did.

We never used a total boat awning, only from the mast aft. These days, we have a cockpit awning, which can also be used to catch rain water, and it does for us. Also, have a 1/2 awning for underway.

It was fairly warm in Fiji, but it didn't stop me baking, and it was only in the Solomons that I baked bread in the pressure cooker on top the stove. Acclimatization is a wonderful thing!

Ann

[roverhi]

Anchoring out with an awning over the cabin/cockpit and a windscoop for he forehatch works a wonder.

We had a pup tent affair made that tied to the staysail stay at the bow in the middle and to the life line stanchions on either side, It ended just aft of the forehatch where it was tied down to the cabin top. Made a super windscoop that made for a cooling breeze for most of the day and also an awning over the foredeck.

The awning had large multi layer patches at stress points. It was tied to the lower shrouds forward, had a spreader bar amidship held up by the main halyard, and fastened to the boom crutch in the stern. Worked fine in almost every anchorage though didn't have the wind common in the Caribbean in French Polynesia. The mid point spreader we left with wasn't very robust and broke soon after we got to the Marquesas. Replaced it with bamboo poles that were plentiful.

[valhalla360]

Originally Posted by StuM

That doesn't work in half the world

Sure it does. It's just if you are south of the equator, north is a bit further off.

But seriously, if you are a full time cruiser not tied to a location, this is actually a legitimate answer. You don't have to stay where it is uncomfortable.

Otherwise, a boat with large and plentiful hatches and shading with tarps/awnings are about the best you can do without air/con. Of course, those come with drawbacks (can't open during rain, you are pressured to anchor out in more bouncy sections of anchorages, if you do go in where it's calm, there is often less breeze).

[chuckr]

one thing we did not see in the above was the bimini top - we painted ours white with elastic roofing paint and really cut the heat in the cockpit - it was blue and now white and reflects the heat and adds additional waterproofing and lets your bimini last longer - ours in 13 years old and we may replace it next year -

[rognvald]

We have never used AC in over 30 years. We use bug screens, fans, a cockpit awning during the day and avoid close proximity to shore when anchoring unless weather dictates otherwise. We enjoy warm weather so are probably more tolerant of heat than those who have depended on AC for most of their lives. It is also part of an overall cruising plan for minimalist sailing with low power consumption. Good luck and safe sailing.