Engine Room Air Conditioning?

I've managed/maintained a few yachts with engine room air conditioning. It does nothing with the machinery running. But it's very good for dropping engine room temperature 8-10F while the vessel is sitting at the dock, which makes a huge difference here in Florida when you're spending a few days in there. Even better if you can block the engine room vents while it's running.

I run 120k BTU of chiller driving nearly 180k BTU of air handlers. Given that I have 9 zones, the human impacts as well as solar means that all zones don’t need full support of the chillers. In fact, my first 60k BTU unit sometimes short cycles due to its ability to drop chiller temps very quickly.

I do think that if I was to make a change it would be to introduce a 24k BTU unit as a sacrificial first phase of chiller to dramatically cut the load on the main two units.

Same. It was such a good decision.

I installed a 24k BTU air handler in the ER. I only use it during maintenance at the dock, and I’m glad it’s there. I also replaced all incandescent lighting with LED to remove those sources of heat.

Also introduced four inline blowers, two for suction and two for exhaust. Before I engage the AC I can push a lot of heat out of the room fairly quickly, and I can keep it cooler when on the genny on the hook.

So worth it. Takes the humidity out of the room also.

For the chiller experts. I'm in the process process of replacement of 3 units 36Kbtu total. On a 44 Viking, Is this a candidate of a switch to a chiller ? Or am I better to stay the course with a combination of splits and stand alone units. Should add only place for the chiller is in the ER.

No, stick with what you have. Running water hoses and everything else to make a chiller work in your size boat will be prohibitively expensive.

I agree, going with a chiller is a must if we ever get healthy enough to buy another boat.

Chillers are good but certainly not problem free. I’ve replaced 5 on two boats in last 6 months.

On the big ships we had air conditioned control rooms within the engine room, but
not on my first ship in 1974: 12,000 HP 2-stroke diesel in the tropics and we were all sweating but stayed skinny because we worked in a sauna.
Yours truly cleaning a boiler, dirty work and the Chief gave us a case of beer and half a day off after the job was done, no air condition.

Since 2 out of 3 are splits and we have to change the copper to the AHs anyway, pulling hoses versus copper, I assume the hose is insulated?

I haven't seen the hoses insulated. The insulation is usually added to the outside and to be correct in Florida like ambient temperatures and for the insulation to last, you have to go with 3/4" thick insulation over the hoses, and it makes each hose 2" or so in diameter, so considerably different as far as running the hoses where the copper ones were. It's a big project to convert a boat that small and much more expensive than just replacing whats there. Not to mentioned I've been waiting between 6-8 weeks for 2 new, 5 ton chillers from Dometic on a 2011 boat whose chillers have failed beyond fixing.

I'm about to order all new stuff anyway, to replace all 3 I'm looking at about $20K labor in. So unless a 2 1/2 ton chiller is more than $15K it might still be worthwhile.
(But I'll admit I know zip about chillers)