We are the proud second owners of 2000 model Hunter 380. We have of course an ice box but are planning to install a refrigeration unit during winter lay-up. Am interested to know the advantages/disadvantages of water cooled versus air cooled units, and what other Hunter owners would recommend based on their experience. Our boat is moored on Lake Ontario (fresh water!) with no plans for salt water cruising on the horizon. We mostly cruise to other yacht clubs and do very little anchoring (e.g. we like all the comforts of home that power offers). Any thoughts/recommendations on brands, etc.? Regards Helmut Trupke
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Probably don't need it
Helmut: I am responding based on a conversation with a refrigeration specialist, not my personal exoerience. However, When my A/B unit needed some repair, the tech guy told me the water cooled portion of my system did not need to be functional (My unit is Air and water cooled). His reasoning was that the additional cooling provided by the water was only necessary in very high ambiant temperature environments, like the islands. SInce our great lakes summers don't hold a candle to the hot island environs, he suggested not spending the $ to repair the water pump....... Jeff
Helmut: I am responding based on a conversation with a refrigeration specialist, not my personal exoerience. However, When my A/B unit needed some repair, the tech guy told me the water cooled portion of my system did not need to be functional (My unit is Air and water cooled). His reasoning was that the additional cooling provided by the water was only necessary in very high ambiant temperature environments, like the islands. SInce our great lakes summers don't hold a candle to the hot island environs, he suggested not spending the $ to repair the water pump....... Jeff
Ambient temp the issue
The main differences for air v. water cooling are related to the ambient temperature you'll be operating in and the higher heat capacity water has compared to air. If you'll be mostly in the tropics (probably not in Ont.) where the air temp is high and the water temp is too the water cooling is more efficient than air. You also don't want to be pumping more heat into the cabin so having water cooling also helps by dumping the heat overboard. Where you are you may want the extra heat an air cooled unit will add to the cabin and being in a colder climate you would probably want to avoid the extra expense and complexity of a water cooled system. I've got a Grunert water cooled system with holdover plates (Florida) and it works fine. Being at a dock all the time I'd think something like and A-B Super Cold Machine would be good. Good luck, Jim h37.5 Prospect
The main differences for air v. water cooling are related to the ambient temperature you'll be operating in and the higher heat capacity water has compared to air. If you'll be mostly in the tropics (probably not in Ont.) where the air temp is high and the water temp is too the water cooling is more efficient than air. You also don't want to be pumping more heat into the cabin so having water cooling also helps by dumping the heat overboard. Where you are you may want the extra heat an air cooled unit will add to the cabin and being in a colder climate you would probably want to avoid the extra expense and complexity of a water cooled system. I've got a Grunert water cooled system with holdover plates (Florida) and it works fine. Being at a dock all the time I'd think something like and A-B Super Cold Machine would be good. Good luck, Jim h37.5 Prospect
downsides
The two major downsides to water-cooled systems are: 1. increased noise from the water pump, which makes far more noise than the compressor itself; 2. an additional two thru-hulls are needed in the boat. The upside, of course, is that they work better in hot climes, which is why I have one aboard Buoyant. Probably wouldn't, though, if I lived in Canada.
The two major downsides to water-cooled systems are: 1. increased noise from the water pump, which makes far more noise than the compressor itself; 2. an additional two thru-hulls are needed in the boat. The upside, of course, is that they work better in hot climes, which is why I have one aboard Buoyant. Probably wouldn't, though, if I lived in Canada.
Think about where the cooling air comes from
I would give some thought as to where the air is coming from that goes through your cooling coils. If your unit is in the engine compartment, and you suck engine compartment air, it's going to be less effecient anytime there is warm air in there. If you can locate the unit, or duct air, so that the air comes from a place that is cool, you'll probably do more good in your location than water cooling would do. For example, my unit is located under the cockpit seat, but it sucks air through a grill in the galley. I was once on a delivery where the muffler developed a leak. The AB unit was back in the engine compartment, recirculating the engine compartment air. It quite working completely, as the air was as hot as the coils. (It began working againwhen we arrived a couple days later and the engine compartment cooled down) I hear a lot of stories of the water pumps for these units quitting. They aren't cheap, either. You could probably buy a higher output alternator for what the pump kit costs.
I would give some thought as to where the air is coming from that goes through your cooling coils. If your unit is in the engine compartment, and you suck engine compartment air, it's going to be less effecient anytime there is warm air in there. If you can locate the unit, or duct air, so that the air comes from a place that is cool, you'll probably do more good in your location than water cooling would do. For example, my unit is located under the cockpit seat, but it sucks air through a grill in the galley. I was once on a delivery where the muffler developed a leak. The AB unit was back in the engine compartment, recirculating the engine compartment air. It quite working completely, as the air was as hot as the coils. (It began working againwhen we arrived a couple days later and the engine compartment cooled down) I hear a lot of stories of the water pumps for these units quitting. They aren't cheap, either. You could probably buy a higher output alternator for what the pump kit costs.
Water pump noise solved
John's right, the factory water pumps we had drove us nuts with their whine, which comes from their internal cooling fans. To preserve sanity, I replaced them with CalPumps, which are internally oil cooled, and whisper-quiet. Toronto can have some hot summer days, but generally the water cooling, while nice, shouldn't be necessary there. If you go with air, cooling, I'd try to keep the ambient temp from building up down below due to greenhouse effect in the summer, though, by keeping the boat well ventillated
John's right, the factory water pumps we had drove us nuts with their whine, which comes from their internal cooling fans. To preserve sanity, I replaced them with CalPumps, which are internally oil cooled, and whisper-quiet. Toronto can have some hot summer days, but generally the water cooling, while nice, shouldn't be necessary there. If you go with air, cooling, I'd try to keep the ambient temp from building up down below due to greenhouse effect in the summer, though, by keeping the boat well ventillated
water cool refers
All you have to do is to buy a refrigerator with a water heat exchanger thruhull instead of an air radiator or a pump to send water into the boat and then back out. There are no moving parts or electrical use and only one hole for a thruhull. Always it is more efficient.
All you have to do is to buy a refrigerator with a water heat exchanger thruhull instead of an air radiator or a pump to send water into the boat and then back out. There are no moving parts or electrical use and only one hole for a thruhull. Always it is more efficient.
heat exchangers
Okay, wasn't going to say this, but since Ron brought up the heat-exchanger thing, I'll mention that a power-boat buddy of mine ran a heat exchanger from his refer compressor into his fuel tank. No thru-hulls at all. Works pretty good if you never let the tanks dip below 200 gallons.
Okay, wasn't going to say this, but since Ron brought up the heat-exchanger thing, I'll mention that a power-boat buddy of mine ran a heat exchanger from his refer compressor into his fuel tank. No thru-hulls at all. Works pretty good if you never let the tanks dip below 200 gallons.
Bryce
The web site is: www.calpump.com. I bought mine at either West Marine or BoatUS... I don't recall which, but I bet both carry them. Just size it comparably in gallons per hour to the old Jabsco or whatever was installed with the refrigerator, or if it is a new installation, whatever flow rate the manufacturer recommends.
The web site is: www.calpump.com. I bought mine at either West Marine or BoatUS... I don't recall which, but I bet both carry them. Just size it comparably in gallons per hour to the old Jabsco or whatever was installed with the refrigerator, or if it is a new installation, whatever flow rate the manufacturer recommends.
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