Silencing AC coolant splash

GTBecker · **Posted:** Thu Jun 28, 2012 10:05 pm

I used to sail and lived aboard for a while, long enough to become irritated by neighboring boats with running ACs whose coolant through-hull splash drove me nuts at night. I'm now in a small cruiser and have become one of those whose AC coolant splashes at night - but don't want to annoy slip neighbors. For some time I've thought about how to silence mine but found nothing both effective and simple.

A solution drifted by one night - a floating board. I tied a short line to each end of an old 2"x8" dock board and secured it so that the coolant outflow lands on it instead of the water surface; the result is blissfully virtually silent. Some refinement is necessary but it's a start toward a real solution, I think. FYI.

298VISTA2000 · **Posted:** Fri Jun 29, 2012 6:31 am

Good idea because I have a feeling my AC will be working overtime for the next few days. :shock:

It hasn't been this hot in Atlanta since the early 80's. Thank God the humidity will be in the low 40's or it would be unbearable.

ric · **Posted:** Fri Jun 29, 2012 7:15 am

People pay a lot of money for those waterfall noise machines!

jsimon · **Posted:** Fri Jun 29, 2012 8:44 am

I have seen people who slip most of the time push a clear hose in the outlet and let it hang down just above the water line. Made it quiet and also depending on water conditions, didn't leave any water staining down the hull.

wkearney99 · **Posted:** Mon Jul 02, 2012 11:49 am

Ditto on the clear hose. Just make sure to remember to remove it. You wouldn't want that added length of hose in there when you dock. Wouldn't want the extended hose to crack the through-hull. Also don't use too large a hose as the force of jamming it in there would put strain on the through hull. If it's a metal through-hull it's less of a problem, but a plastic one that's been out in the sun for many years might be more brittle than you'd think...

Floating stuff is problematic because you won't have an easy way to keep it stuck out there at exactly the right point, and have it stay there under all conditions (and not come back and bang into your boat). Tide, wind, waves will all move the boat enough to make for a real challenge keeping the 'target' in the right place.

When we had some AC-less ragbaggers next to us the solution was for us to move to a different slip, next to someone that had AC also.

The hassle at the moment is we lost power at both the marina in Annapolis and the house in Bethesda. We have a generator at the house (which raises it's own issues with neighbors) but at the marina it'll be a hassle if power's out for more than a few days. Especially if it's not back on by the 4th. Can't run a genset at the dock due to noise and fumes, for us or other boats nearby.

GTBecker · **Posted:** Mon Jul 02, 2012 1:01 pm

Why does the effluent through-hull need to be above the water line? Sacrilege, maybe, but - if equipped with a seacock that's as accessible as the inlet - why not?

GTBecker · **Posted:** Mon Jul 02, 2012 1:13 pm

> ... We have a generator at the house...

As do we. I've found there is no need to fear neighbors' envy or rath - so long as you have a spare fridge in the garage that they can use to save some food, and you shut the genset down at 11PM or so. We've survived two hurricane outages here, one for four days, and the neighbors were glad we had the generator.

It's the folks who managed to find a portable generator in stock at Home Depot after the storm who seem to more often selfishly run them all night long, I think, than do the permanent owners.

ric · **Posted:** Mon Jul 02, 2012 3:10 pm

You can pick up a Yamaha EF2000iS on amazon for 989 shipped. Zero noise issues. Sometimes Yamaha puts the on sale in the $700 range.

wkearney99 · **Posted:** Mon Jul 02, 2012 3:25 pm

GTBecker wrote:

Why does the effluent through-hull need to be above the water line? Sacrilege, maybe, but - if equipped with a seacock that's as accessible as the inlet - why not?

I'd imagine there's a good reason. One might be pressure, especially if it's running while underway. It's one thing to have the rushing water pushing on the intake side, but on the exhaust I'd imagine it'd be a problem. But I'm guessing the real reason would be the need for two seacocks, nowhere close to each other. You can't have the discharge water being pulled back into the system because of the way a heat pump works.

This link gives some interesting advice: http://www.paradiseyachtsales.net/cruisingcenter16.html

wkearney99 · **Posted:** Mon Jul 02, 2012 3:27 pm

ric wrote:

You can pick up a Yamaha EF2000iS....

Which are not constant duty cycle devices. Let's not hijack the thread onto generator discussions.

Suffice to say if you're dealing with a multi-day outage and you want to keep anything more than a fridge running off/on periodically you're not going to be doing it reliably OR safely with a portable unit.

GTBecker · **Posted:** Mon Jul 02, 2012 9:17 pm

wkearney99 wrote:

... guessing the real reason would be the need for two seacocks, nowhere close to each other...

Could be. I wonder if a reversed scoop, on the other side of the keel line, would both draw water when underway - and avoid a thermal loop back to the intake when stationary. Running some hose to allow placing the two seacocks in similar positions on opposite sides might be practical. I'll talk to Mermaid tomorrow.

wkearney99 · **Posted:** Tue Jul 03, 2012 6:49 am

When looking a bit online the one thing that stands out is an out of the water discharge line is necessary for monitoring the flow rate and temperature. If the line was below water you wouldn't be able to confirm that the system is working properly.

I also noticed the recommended height for the discharge point is between 4" and 8" above the water line, and that any higher makes too much noise. I've not measured where mine is situated but if I was guessing I'd say it might be higher than that.

There's also the question of siphon effect. I saw at least one setup that used a pinhole at the top of a discharge elbow/hose as a way to avoid siphon suction action.

So if I were thinking of changing the discharge my first call would be to the AC vendor. Talk with them about it first.

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Silencing AC coolant splash

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