Why electric AC?

[wingssail]

Originally Posted by skipmac

Screens work for mosquitoes and flies but they can't keep out noseeums, they're too small.

And screens block a lot of the breeze, so if it's already hot, humid and calm the screens will take away what little ventilation there is.

But again, it's not often this combination occurs. Two+ years liveaboard in the Bahamas and Caribbean I can only remember 4-5 nights that it was unpleasant. For me that isn't enough to justify a large, diesel gennie but I like having the little Honda anyway and it works for occasional use.

Screens can work against Noseeums.

We made our own 5 screens 23 years ago using wedding veil fabric. It is very fine mesh material. Flies, mozzies, bees, noseeums, everything, is excluded. Breeze however, passes through, mostly due to the huge bow hatch.

With the screens on, the shade awning up, and fans running in the cabin, we are cool enough, at anchor, even on very hot days in Mexico summer and every other place and time that we used them in the last 23 years. At night, at anchor, once the sun goes down it is even cooler in the boat and pleasant for sleeping with a fan blowing. In a marina we need the air-conditioner which runs on shore power.

These screens are still usable now 23 years later and we used them during most of our cruise this spring (three months) however several of them have developed holes or tears which we patched with tape. Since we bought a few extra yards of wedding veil material back then we have enough now for a whole new set. We've dug out that material and it is like new. We'll use the old slit Dacron edges and put in new material. It's on the project list.

[RaymondR]

I went to the camping store and bought a very fine bug net and cut it up and used it for screening all the hatches. Whilst it worked very well for excluding even the no-see-ems the UV rotted it within a couple of years.

My latest experiment for the deck hatches is the knitted shade cloth sort of throw rugs with old mooring line around the edges to keep it weighted down onto the deck. The large tented area of fine mesh appears to allow plenty of air through to my in-hatch auto radiator 12V fans as well as plenty of light.

[Dockhead]

Originally Posted by skipmac

Screens work for mosquitoes and flies but they can't keep out noseeums, they're too small.

And screens block a lot of the breeze, so if it's already hot, humid and calm the screens will take away what little ventilation there is.

But again, it's not often this combination occurs. Two+ years liveaboard in the Bahamas and Caribbean I can only remember 4-5 nights that it was unpleasant. For me that isn't enough to justify a large, diesel gennie but I like having the little Honda anyway and it works for occasional use.

Someone should write a book about insects and cruising at different latitudes.

This summer I was up at the top of the Gulf of Bothnia with my boat, just 30 miles from the Arctic Circle, and the mosquitoes were brutal, driving one of my crewmen nearly insane (he has sweeter blood than I).

Now I'm back to only just above 60N and it's not so bad. I've even put the hatch screens back in their long term storage.

So maybe across a broad swath of the Temperate Zone it's not so bad with the insects, until you get down there nearer the Tropics.


Air conditioning? Not a consideration up here.

[valhalla360]

Originally Posted by EngineerRetired

With a genset the diesel runs at at a constant speed to turn a generator that produces electricity that is used to spin an electric motor, that turns a compressor. I am proposing driving the compressor directly with the diesel. It's RPM can can easily be altered to meet demand. Get the boat cooled off or only cool one cabin and the RPM can drop to a fraction of full RPM.

Less fuel, longer life, not nearly as expensive. When not being used used for the AC, the same small diesel can charge house batteries or run the water maker directly.

Again, this is all off the shelf tech and should be fairly low cost to build.

Inverter generators already do all this.

Running the air/con in your car off the engine makes sense because people don't spend a lot of time in their car unless the engine is running. Cruising boats on the other hand typically aren't running the main engines most of the time.

Could you build a rube goldberg system with belts and pulleys? Sure but seriously doubt you would gain enough efficiency to buy a beer once a month...and when the time comes to sell, buyers will price in ripping it out and putting in a standard system.

PS: No seeum screens are almost as good as windows at stopping a breeze.

[Simi 60]

Originally Posted by EngineerRetired

I suppose the reason the AC units on most boats are electrical is so they can be ran from shore power. For real cruisers and more active boaters, wouldn't a system ran by a small diesel be better?

Even better is the well thought out and designed boat that doesn't need A/C
5 years full time in sub tropical to tropical waters and never wished for it once.

[skipmac]

Originally Posted by RaymondR

I went to the camping store and bought a very fine bug net and cut it up and used it for screening all the hatches. Whilst it worked very well for excluding even the no-see-ems the UV rotted it within a couple of years.

My latest experiment for the deck hatches is the knitted shade cloth sort of throw rugs with old mooring line around the edges to keep it weighted down onto the deck. The large tented area of fine mesh appears to allow plenty of air through to my in-hatch auto radiator 12V fans as well as plenty of light.

Interesting fan setup. I made one just the same but using a large 12V RV fan. I set mine to blow up and out. That way it sucks air in through all the ports and hatches and, if there's a very light rain in the middle of the night it will blow the water up and save you from getting up to close the hatch, sometimes.

Nice and quiet and more air than the little cabin fans like the Caframo but not as much as a 120VAC window fan. How's the flow with the radiator fan? Noise level?

[skipmac]

Originally Posted by Dockhead

Someone should write a book about insects and cruising at different latitudes.

Oh absolutely. Most of my experience has been FL and the tropics but getting more time in the NE US. Found mosquitoes and noseeums can be just as bad here as around a Florida mangrove swamp. Also black flies in the summer that we don't see in Florida but then they have yellow flies that do the same job.

Friend takes a fishing trip to Canada every summer and tells me he can't leave the tent without long sleeves, gloves and a hat with a net like a beekeepers hat.

Haven't had the pleasure but also hear horror stories about Scottish midges and a similar critter on the south island of New Zealand.

Originally Posted by Dockhead

Air conditioning? Not a consideration up here.

Most of the time but even Europe gets an occasional heat wave. When we did the river cruise in July in central France we got to experience a heat wave for 2-3 days. It was so hot (that being said by someone that has lived in Florida for 40 years) that by 11-12:00 we had to tie up and hide below until almost 6:00 pm. Even friends in London and Manchester occasionally bemoan the lack of ac.

[skipmac]

Originally Posted by valhalla360

PS: No seeum screens are almost as good as windows at stopping a breeze.

Yep. That was my experience. Mesh fine enough to stop the noseeums will pretty much block a light breeze.

I have read about a trick that claims to keep out the noseeums. Basically wet the screens with something that repels them. Several suggest diesel but the smell kills that idea for me. Maybe spray the screens with some kind of insect repellant might work but the few times I had the problem I had nothing on board. Poor planning I guess.

[Dockhead]

Originally Posted by skipmac

. . Most of the time but even Europe gets an occasional heat wave. When we did the river cruise in July in central France we got to experience a heat wave for 2-3 days. It was so hot (that being said by someone that has lived in Florida for 40 years) that by 11-12:00 we had to tie up and hide below until almost 6:00 pm. Even friends in London and Manchester occasionally bemoan the lack of ac.

By "up here", I didn't mean Central France. I'm sitting here above 60N, the latitude of Anchorage Alaska.


We did have some uncomfortably hot weather "up here" last summer, which was record-breaking, but still nothing that would seriously make anyone think about air conditioning. God, I hate hot weather.

[RaymondR]

Originally Posted by skipmac

Interesting fan setup. I made one just the same but using a large 12V RV fan. I set mine to blow up and out. That way it sucks air in through all the ports and hatches and, if there's a very light rain in the middle of the night it will blow the water up and save you from getting up to close the hatch, sometimes.

Nice and quiet and more air than the little cabin fans like the Caframo but not as much as a 120VAC window fan. How's the flow with the radiator fan? Noise level?

Full on with 12V connected they blow a gale and roar so I wire them in series and use a speed controller to adjust both air flow and noise to an acceptable level.

One of the advantageous things about using radiator fans is that they are designed to operate in the front of the vehicle where they are exposed to high levels of water spray and consequently getting wet in the rain does not bother them.

[skipmac]

Originally Posted by Dockhead

By "up here", I didn't mean Central France. I'm sitting here above 60N, the latitude of Anchorage Alaska.


We did have some uncomfortably hot weather "up here" last summer, which was record-breaking, but still nothing that would seriously make anyone think about air conditioning. God, I hate hot weather.

For us colonials even central France is "up there", as in as far north as Nova Scotia.

A lot of people on this side of the pond don't realize quite how far north western Europe is: UK about the same latitude as Labrador. Even the southern UK is above 50N, something to think about when sailors talk about the storms in the roaring 40s in the southern hemisphere. Of course very different weather dynamics but still something to keep in mind.

Regarding hot vs cold, quite agree. Would much rather be cold, up to a certain point, than hot. Have had to give up on summer in Florida as just unbearable.

My father once pointed out (in a "negotiation" with my mother about the setting of the ac in the car) that one can always put on more clothes if too cold but if too hot there just so far one can go.

[skipmac]

Originally Posted by RaymondR

Full on with 12V connected they blow a gale and roar so I wire them in series and use a speed controller to adjust both air flow and noise to an acceptable level.

One of the advantageous things about using radiator fans is that they are designed to operate in the front of the vehicle where they are exposed to high levels of water spray and consequently getting wet in the rain does not bother them.

All very interesting points. Think I'll have to visit the local junk yard and pull a couple for some R&D.

[wingssail]

Originally Posted by Dockhead

...God, I hate hot weather.

Try sailing in shorts some time, you might like it.

We've lived in the tropics for 15 years. It's grows on you. As far as I can tell, life in the hot weather goes on as normal. but...

it surely constrains one's outside activities, so we don't work on the deck much during summer, (two hours work outside max per day) and going sailing means putting the boat away afterwards, which is pretty tough in the hot afternoon sun, so we sail less in the summer.

But at anchor it's not too bad, and in the marina, we do have AC.

[Dockhead]

Originally Posted by wingssail

Try sailing in shorts some time, you might like it.

We've lived in the tropics for 15 years. It's grows on you. As far as I can tell, life in the hot weather goes on as normal. but...

it surely constrains one's outside activities, so we don't work on the deck much during summer, (two hours work outside max per day) and going sailing means putting the boat away afterwards, which is pretty tough in the hot afternoon sun, so we sail less in the summer.

But at anchor it's not too bad, and in the marina, we do have AC.

To each his own.


I grew up in a hot place but tolerate it badly now in this stage of life.


Cold on the other hand doesn't bother me -- just add clothes. When it's too hot, there's nothing you can do. Therefore I like Northern places and high latitudes.


I'm going to Spain tomorrow and am a little bit dreading the 30+ temps they're having there. Yes, I'll be sailing in shorts

[RaymondR]

Originally Posted by Dockhead

To each his own.


I grew up in a hot place but tolerate it badly now in this stage of life.


Cold on the other hand doesn't bother me -- just add clothes. When it's too hot, there's nothing you can do. Therefore I like Northern places and high latitudes.


I'm going to Spain tomorrow and am a little bit dreading the 30+ temps they're having there. Yes, I'll be sailing in shorts

Same situation re onset of senior citizenship but don't like the cold and having to wear all those clothes all the time and being very tall and a hard time keeping my feet warm.

Summer heat in Australia starting to knock me about a bit though so I might have to start lurking about in marinas with an air conditioner.

I already have a 5.5 hp gas engine with a couple of belt driven alternators in a box on deck for contingency battery charging and am thinking of replacing one of the alternators with an auto aircon compressor and using one of those bus rooftop condensing units in a hatch as an alternative to marinas which I don't like because of the cockroaches and rodents and some of the non human wildlife that tends to inhabit them waiting to infest a vessel.