Inside your boat....hotter or cooler than outdoor temps?

[SecondBase]

I am have internal and external thermometers. With a little attention to solid awning shade and ventilation I'm able to equalize the two temperatures.

I have a bow awning from mast to pulpit.

I have an awning over the pilot house. A tarp which can be shifted with the sun.

I had sunbrella covers and I then added phiffertex screens. For the phiffertex layer I used not sure the name but "middle snaps".

This gave me options: just phiffertex or that plus the sunbrella top layer. That part worked relatively well.

I was using car windshield reflectors and I had put the solar reflector inside the pilot house. What I recently learned from the Boat Galley (subscribe - it is way more than cooking info) is to take the solar reflector, trim it and place that under the phiffertex--outside the windows.

They have a link to a good reflective material and I'll probably upgrade from the car stuff. Anyway there article helped me resolve the hotter cooler problem.

https://theboatgalley.com/sun-covers-for-windows/

[Tetepare]

My boat is closed up during the week. Last year I finally installed a solar vent fan- it makes a huge difference, dropping the inside temperature a full 10F.

Also, pouring water over a hot deck will cool the deck, and decrease heat radiation into the cabin.

I'll admit- when it's 85F at night and no wind, I sometimes run to the dock where I plug in the portable A/C. If nowhere near a dock and I'm staying on the hook, I find that a dip in the water will cool my temperature enough to get to sleep.

[Leo Ticheli]

I've used multi-ply duct insulation cut to fit in the windows, held in place by hook & loop dots, and it helps, but in Florida only air conditioning makes my boat livable at the marina. If there's no wind at anchor it can be miserable as well.

Whoever figures out a way to cool a boat without connecting to the mains or burning gas or diesel will have a bronze statue erected in their honor.

We have engineering geniuses on this forum; someone save us, or at least tell us if this thing will work to cool one cabin for sleeping: Zero-Breeze.

Fair winds,

Leo

[softdown]

Thanks folks! Lots of great info and interesting ideas here.

As for me, I built this 8000 foot shop and it is solar, solar, solar! No A/C and I heat with about $100 worth of propane to get me through Colorado's second coldest winters. I used three layer "greenhouse glass" to capture thermal heat. A lot of insulation to retain the heat of course. Solar panels adorn the sunroom roof. Presently fine tuning fans to automatically(maybe) push cool air into warmer rooms.

I don't know what my rational is exactly for choosing a lifestyle that has many similarities to "deluxe camping". Guess I like the simple life in many ways.

I will be spending considerable time on the solar aspects on my liveaboard project. Which is probably 2-5 years away.

Has anybody tried a mister over their boats cabin? For evaporative cooling?

In dry regions, swamp coolers can be effective. Doubtful utility with the every present humidity of boating....as in almost no way.

Right now I fear that I will occasionally employ an a/c unit.

[Formosa Scott]

Originally Posted by softdown

Has anybody tried a mister over their boats cabin? For evaporative cooling?

In dry regions, swamp coolers can be effective. Doubtful utility with the every present humidity of boating....as in almost no way.

Right now I fear that I will occasionally employ an a/c unit.

I have considered this, a small pump on solar would work but..I am afraid of what the boat would look like spraying seawater over it in the sun then air drying at night, I think you would have a green boat.

[softdown]

Originally Posted by Formosa Scott

I have considered this, a small pump on solar would work but..I am afraid of what the boat would look like spraying seawater over it in the sun then air drying at night, I think you would have a green boat.

Pretty sure that misting saltwater would turn almost everything into rust within a month. I need to learn to specify freshwater vs saltwater.

[model 10]

Originally Posted by softdown

Pretty sure that misting saltwater would turn almost everything into rust within a month. I need to learn to specify freshwater vs saltwater.

I've seen some boats with misters in the cockpit. Maybe using just RO water and a 115v ac pump and the inverter etc. Sounds pretty lux in the calm anchorage.

[kelbylinn]

Our homeport is in the Deep South on Dauphin Island, AL (mouth of Mobile Bay). We take our longer trips down the Florida West Coast. I can't imagine trying to get by without air conditioning for around 7 or 8 months of the year, and still enjoying the live-aboard or extensive cruising times on board. If on docks with power, then the AC systems just make life much better. If doing a lot of anchoring or on a mooring, obviously a generator would also have to be available to run the AC system(s). This week for example here in Alabama, we have been hitting the mid 90's every day with high humidity. Food for thought...

[mikedefieslife]

If you count the solar extractors, i have 8 fans. Makes little difference. The boat still gets hotter than you'd like. Btw I'm at anchor with all the hatches and portlights open too. The boat doesn't really cool down until dawn.

[hafa]

Here in the most consistent climate on earth, where it's always 80F, our boat gets unbearably hot if it's closed up, and is reasonably comfortable when all hatches are open, as we've many hatches and there's usually enough of a breeze to maintain the internal temperatures at ambient. There's no heat loading to speak of.

I don't use aircon in the car, at home, or in the boat. I chose my climate for a reason...

[zeehag]

i am on board all year long. i use home depot screening from the garden section--i have beige, green and black. the best ones are the dark ones to prevent pain in eyes and keep heat down.
inside that for the rainy season i place waterproof tarping/awnings/covers so i keep dry . formosas donot like fresh water much.
inside once temp rises over 80f, i use air conditioner as my cat seems happier with that. i used to tough it out until it got to be 100 before air cond. fts, mon. i like comfort, this is my home.

donot forget--air temp is not the only factor in interior temp..hahahahaha when the anchorage reaches 100 f under boat, you aint gonnabe happy for nothin/
then yer in a marina for cane season with air conditioning and puter use rises.

[Miz Pea]

Surprised no one has mentioned how much cooler a white hull is than any other color. The darker colors (green, red, dark blue) absorb much more heat from the sun. A white hull is the only way to go in the tropics and sub-tropics, unless one has an unlimited budget for running the genny.

And as Zeehag mentioned, once the water gets to too hot to swim, it becomes pretty unbearable, and the "fire up the genny" tipping point is reached, no matter the color of your hull. (And the older I get, that tipping point temperature keeps getting lower and lower.)

[mikedefieslife]

Originally Posted by Miz Pea

Surprised no one has mentioned how much cooler a white hull is than any other color. The darker colors (green, red, dark blue) absorb much more heat from the sun. A white hull is the only way to go in the tropics and sub-tropics, unless one has an unlimited budget for running the genny.

And as Zeehag mentioned, once the water gets to too hot to swim, it becomes pretty unbearable, and the "fire up the genny" tipping point is reached, no matter the color of your hull. (And the older I get, that tipping point temperature keeps getting lower and lower.)

Of course the white hull will also retain more of the heat it does absorb, where as a darker one will radiate it back into the atmosphere.

Thickness is more important than colour. At least in a study of clothing worn by Bedouin tribes in the Sahara, who nearly all wear dark clothing.

Still, I know I'd much rather walk on a white deck than a dark coloured one.

[Leo Ticheli]

Does this have any practical value on our sailboats? Perhaps if the bottles could be cut much shorter and glued together then placed in the opening of the wind scoop it could work.

They screw plastic bottles to a piece of cardboard and hang it in the window. The air flows differently now.

I understand that storage space is no small concern and I'm not all that confident it could make a significant, if any difference. Thoughts from smarter physics minds than mine?

I believe there would be a huge market for a small, 12v air conditioner, just powerful enough to cool a single cabin. With solar growing cheaper, the batteries could be charged during the day and then run the machine at night.

If anyone knows of such a device, I'm past ready to sign up!

Fair winds,

Leo

[Formosa Scott]

https://www.westmarine.com/buy/pompa...hoCZuMQAvD_BwE