How many btu's needed to cool my 40'?

[luvitt]

im gonna buy a window unit and put it in the forward hatch. I have an onboard 12k btu system, but i havent finished setting it up. it's so darn hot, I cant breathe. I need something temporary just so i can work on the boat. I felt sick today b/c i was so hot.

How many btu's do you think would do a good job? I have a 10k btu portable unit with the hoses in the aft cabin. It barely keeps it comfortable with the doors shut to the room. i think its pretty inefficient, as i have the hoses taped to a piece of cardboard with holes cut in it, and taped to the porthole. It leaks a lot of air im sure.

 

[Allan R]

I would suggest at a bare minimum, 16,000. If you can do more, by all means do so.

 

[RichH]

im gonna buy a window unit and put it in the forward hatch. I have an onboard 12k btu system, but i havent finished setting it up. it's so darn hot, I cant breathe. I need something temporary just so i can work on the boat. I felt sick today b/c i was so hot.

How many btu's do you think would do a good job? I have a 10k btu portable unit with the hoses in the aft cabin. It barely keeps it comfortable with the doors shut to the room. i think its pretty inefficient, as i have the hoses taped to a piece of cardboard with holes cut in it, and taped to the porthole. It leaks a lot of air im sure.

16,000 to 20,000 Btu is usually recommended for a 40 ft. boat depending on its location. go to the www.DometicEnviro.com website - mfgr. of CruiseAir and MarineAir AC units.

 

[Rich Stidger]

In my h40.5 the factory put a 16K BTU for the main salon and vee berth and a separate 5K BTU for the aft cabin.

They do a great job for both cooling and heating.

 

[Bill Roosa]

Me too

I have the factory 16/5 k BTU also on my 40.5. Work great but man do they suck up the room and I have to connect another shore power line to supply the electrons.
ABSOLUTLY USELESS at anchor.

 

[Ross]

You can't get cooler than the dew point in the cabin. it takes a 1000 btu's to condense one pound of water from the air but that same 1k btu's will cool 1000 cubic feet of air 13 degrees.

 

[Dan Johnson]

Bro...

it sounds like you could use some hatch covers or a canvas fly set to shade the boat from bow to stearn to cut down the deck heating enough for the a/c units to work more effectively.

 

[Paul Mermelstein]

Re: Bro...

My Beneteau 393 (39.3 ft) came with a 12k unit for the salon and forward cabin and a 9k unit for the aft cabin. Works very well.

 

[Blitz]

Hatch Covers Work

it sounds like you could use some hatch covers or a canvas fly set to shade the boat from bow to stearn to cut down the deck heating enough for the a/c units to work more effectively.

Hatch covers keep the boat a lot cooler even without AC - and I'm very pleased with the ones I purchased right here on sbo.

 

[Snotter]

My Morgan 41 OI has a 16000 unit in the forward cabin and a 9000 unit in the aft. Though it takes awhile, it cools the boat down nicely in 100 degree heat.

 

[luvitt]

how do you go about hanging a tarp over the boat? I can see making a "tent" over the boom but I don't see how I could easily shade it from the bow to the stern. do people just rig it up w bungie cords or something? or is there a standard method for this. I have been keeping an eye out in my marina but haven't really seen anything but a custom piece of canvas covering the bow of one boat. its kinda like a tent that clips on low at the bow, and the aft end onnects to the mast about 6' up and the corners of the canvas are slanting down and have straps that lead down to the toerail. it isn't just a flat tarp, it has a shape to it. but it really doesn't look that big, its kinda skinny compared to the beam of the boat.

 

[Ron20324]

I have been keeping an eye out in my marina but haven't really seen anything but a custom piece of canvas covering the bow of one boat. its kinda like a tent that clips on low at the bow, and the aft end onnects to the mast about 6' up and the corners of the canvas are slanting down and have straps that lead down to the toerail. it isn't just a flat tarp, it has a shape to it. but it really doesn't look that big, its kinda skinny compared to the beam of the boat.

That "custom canvas" is what the world-cruisers do. Shade as much of the boat as you can- if not all of it. I have seen pictures of that bow canvas, but it was strung so high up that the sun came in underneath and hit the deck like the canvas wasn't even there. Taking it down to the toe rail may prevent air flow across the deck.

 

[Stu Jackson]

The Pardey's method of doing it is to take a small piece of canvas and keep moving it around to a follow the sun.

 

[Allan R]

Shadtree

There is a company on the web that sells what you may be looking for "Shadetree". It looks that it might do the trick for several $$$.

http://www.intheshd.com/

 

[luvitt]

i ended up buying a 10500 btu window unit. I already have a 10k btu portable in the aft cabin, so i got a total of 20500 btu. good enough for now, at least i will keep cool while i am working on the self contained sea water unit. it is 12k btu, so i can get rid of the window unit and have 22500 btu. hopefully that's good.

i just hate to look like a hobo in my marina. i don't really see anybody else doing this. im parked right next to a $2mil trawler. my buddy does it, but his is small and in his companionway and it cant be seen. i'm gonna put it in my fwd hatch b/c my companionway hatch is small, only 2 little hatchboards. the unit is taller than that.