Air Com

jfm said:
Perleeeese Pete. You've got a v nice boat there and it would be crazy to spoil it with a big white box that would get in the way and which you'd hate as soon as you first used the boat with it. Get a proper unit, ffs. You only need a completely hidden 16000 btu/hr selfie to get things started
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+1
Phone round all the air con companies & ask if the know of anyone with a used unit / system they have replaced.
 
jrudge said:
Pete.

If doing it do it right and do the aft cabin as well.

On my t40 there was a 12k unit under stairs for saloon and aft and a 7k for front cabin.
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I think that supports my theory that 12k for front cabin and saloon will suffice. Or 16k if I can get a duct from saloon to aft cabin too.

Saying that, the space under the sofa looks pretty tight to me so I'm not yet convinced a cooler with go under there anyway.
 
petem said:
W, I'm not bothered about cooling the aft cabin but I did wonder if 12k might be sufficient to cool the forward cabin and the saloon. JTB quoted 16k for his T40 which is quite a big bigger than my boat which might support this theory.

I did read somewhere that too high a capacity can actually be a negative.
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If it is an HFL unit or whatever Fairline came fitted with in late nineties you need 16k or more. (crap units)
If Condaria 8k will do it, as it even cools Cranchi 40 Med in the best of Summers.
 
petem said:
I think that supports my theory that 12k for front cabin and saloon will suffice. Or 16k if I can get a duct from saloon to aft cabin too.

Saying that, the space under the sofa looks pretty tight to me so I'm not yet convinced a cooler with go under there anyway.
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The saloon unit used to struggle a bit. I used a 4 inch flexible tumble dryer hose to direct air from front cabin to saloon sometimes if really hot.
 
jimmy_the_builder said:
If the inlet and outlet are at the same depth below waterline - isn't it a zero sum for the pump in terms of back pressure?
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'Tis indeed. It's even a zero sum game if the in/out are at different depths below the waterline. There is a whole chunk of boaters, boatbuilders and airco installers who think discharge shd be above w/line, and it's all nuts imho. My in/outlets are half a metre (out) and a metre (in) below w/line using the logic you state and the thing runs fine (10 tons of refrigeration)
 
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jfm said:
There is a whole chunk of boaters, boatbuilders and airco installers who think discharge shd be above w/line, and it's all nuts imho.
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While I fully agree with your "imho", for the records I was told by a builder several years ago that this is (or at least was) required by some classification societies - RINA surely being one of them.
And with a minimum height above w/l, too - 30cm, IIRC.
Not sure about which level of classification, though (possibly for commercial vessels only).
 
If it were demanded by a cl society and I didn't want to dodge the rule some other way then I'd just fit a neat drop tube outside the hull. Or fit it inside the stuck on GRP "pod" that often covers the exhaust outlet.
 
petem said:
Thu guy at Nauticool recommended the inlet to be towards the bottom of the hull and the outlet to be nearer the surface.
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makes sense to me
If the intake was at 1 meter below seal level there would be 1.45 psig of pressure pushing the water towards the pump, (centrifugal pumps don't like sucking ) and if the discharge outlet was at 250mm below sea level there would be .36 psig of resistive pressure, if the discharge was above sea level there would be 0 psig of resistive pressure. imho

Is there far more a/c units discharging above the water line or do we just notice the ones that are ?
There's a Demo sunseeker predator 68 in our Marina and all you can hear when you walk past is the discharge from the a/c units ( well I'm assuming that what the constant discharge is from )
Does anyone know if both systems even use the same type and size of pumps ?
 
All this "spitting in the water " stuff is none sence ,it's more like pissing in the water Surley ?
The impeller -once the water has gone through that any pressure differential effect ( if i understsnd everybody ?) is lost -period !
If your water pump ( Calpedi ) is man enought it won,t care where the exist is relative to WL -with in reason ,

Main reason for abovevWL exit is so one knows the pump is working etc .
If its at the stern -inside you can,t hear it and most neighbours have A/C going --par for the course .its a none issue .
@ anchor and A/C the Geny needs to run anyhow .
Space out .What do folks expect anchored TOO NEAR a well speced boat ---?
 
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jrudge said:
Pete.

If doing it do it right and do the aft cabin as well.

On my t40 there was a 12k unit under stairs for saloon and aft and a 7k for front cabin.
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Was looking through the boat manual and it rather helpfully has a schematic for the fitment of A/C that shows a 7k Coolmax unit under the forward berth with outputs to the forward cabin, galley and heads and a second 5k Coolmax unit under the vanity basin in the mid cabin with outputs to the saloon and rear cabin.

If you have two chillers do you need two pumps, two thermostats and two sets of sea cocks?
 
I have two pumps, one sea cock & two controllers which regulate temperature & fan speed for each zone
I repaired the a/c on a f37 which had one pump , two electronic controllers again regulating temp and fan speed
The one pump is feed via a control pcb which receives a signal from either controller to energise the pump on demand
I think all new systems use electronic controllers as opposed to thermostats now
 
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