Heating a Mac

[pokerrick1]

They have adjustments on them you know Rich - - - besides I really only use one to heat the aft berth area and dinette - - - the other two I have are spares and/or heat the bow when rarely necessary.

Rick

I was poking fun at your 1500 amps. That works out to about 180,000 watts of heat each. Pretty toasty, alright.

~Rich

Oh - - - did I mean 1,500 Watts Of course I did

Rick

[pokerrick1]

Amps, Watts, Gonzo, Bonzo, Iceberg, Greenberg - - - it's all the same

Rick

[Hamin' X]

Amps, Watts, Gonzo, Bonzo, Iceberg, Greenberg - - - it's all the same

Rick

What's the matter, Rick? Heat getting to you?

~Rich

[pokerrick1]

You talk'n to ME

You think THIS is HEAT

Heat is 30 years ago when some one bet $3,000 at me and I THOUGHT I had the best hand - - - but I only had $3,000.50 to my name and it was ALL ON THE TABLE

This is FUN - - - - NOTHING

Rick

[School House Steve]

I have a MR HEATER which is a portable catalytic heater purchased at Home Depot for under $100. It doesn't produce any carbon monoxide, has a low Oxygen cut off sensor and will shut off if tipped over. It runs off a one pound disposable propane tank, the same as my Magma Bar B Que, or Coleman lantern and stove.

[Moe]

I have a MR HEATER which is a portable catalytic heater...

MR HEATER "Portable Buddy" is NOT a catalytic heater and you will not find it described as such on their website and in any of their material. Unlike a catalytic heater, where no burning or flame takes place, the MR HEATER has a pilot light flame and a ceramic tile burner instead of a catalyic's platinum catalyst.

It doesn't produce any carbon monoxide...

You should qualify that with "if used properly" and I suggest you read your owners manual. From page 3:

When used without adequate combustion and ventilation air, this heater may give off excessive CARBON MONOXIDE, an odorless, poisonous gas.

Yes, it has an oxygen depletion sensor and because of that is considered by some to be safe for indoor use when used properly. What the MR HEATER manual is telling you here is not to bet your life on the ODS. If you are using this or any hydrocarbon fueled heater aboard without a carbon monoxide detector, you're playing Russian Roulette. That also applies to catalytic heaters, as well as the flower pot over the alcohol stove. Even with a detector, you should never use an unvented heater while sleeping.

[edit to add] Carbon monoxide as a result of combustion RISES due to the heat involved. Over a very long period, in still air, it may eventually sink to the floor, but in areas where movement is involved it is likely to remain fairly evenly dispersed. It's more important to have the CO detector reasonably close to the potential source (but not close enough to false alarm from sources like wood stoves that must be opened to refuel). A propane detector most certainly should be installed low and/or in the bilge since it does sink and flow like invisible water.

[Québec 1]

I use a 1500 watt electric heater for warmth in the cold weather and the fan for air only to cool in the summer!
http://us.st12.yimg.com/us.st.yimg.com/ ... _552480074
or my stock origo stove. The electric heater stays on at low setting at night in early spring and late fall when on shore power or with the gen when on the hook before going to bed at night...pretty rare........... and the origo stove when on the hook also keeps us warm whilse keeping the kettle going for tea!
Q1

[Night Sailor]

Moe is correct. My Mr. Heater has a ceramic grid to disperse the flame so more radiant heat is given out the front but it is not catalytic and the open flame of the pilot light is subject to wind blowing it out, even from just carrying it about while lit. I have used my Mr. Heater for two years on Duet, and enjoy it's light weight, toughness, convenience and heat output, but after 40 years of using small propane appliances without mishap, I know to be cautious beyond the maker's manuals. It's particularly important in the small confines of a boat to provide adequate veintilation for both the heater and the crew, and to prevent the condensation buildup that comes from burning organic fuels. Even on teh coldest days I use the boat for sleeping (20s is cold for TX) I keep a four inch intake vent and two 3 inch vents open for circulation.
To reduce the chance of escaping fuel going to the bilges, I place the new fuel cannister on in the cockpit before taking below. When I'm ready for bed I turn it off and place the whole heater in the cockpit for the night. That way it only takes five seconds to light again thet next morning. I only remove the fuel cannister in the cockpit.
I like the safety features like the low oxygen and tip over shutoff features, and the ceramic configuration of the Mr. Heater because it doesn't produce as much moisture as just turning on my propane galley stove. There are lighter weight, smaller heaters available but they do not allow one to focus the heat in one direction or have a high and low heat selection as the Mr. Heater does.
I paid less than $40 US for mine. IF I recall correctily it was from Walmart.

[kmclemore]

Hmm.. I agree about the Mr Heater - it's just ceramic. However, I use a Coleman ProCat heater (link) - that's truly a catalytic, I believe? Moe, what do you think?

[Night Sailor]

A catalytic heater is certainly preferable in my view, and I have used a Coleman catalytic run on alcoho for my tent camping days. But I ended up choosing the Mr. Heater MH9 small Buddy because it used the same fuel as the stove, gave out 4K btu on low, 9K btu on high, didn't seem so top heavy, fit in a narrower locker space, and was designed so it could be mounted on the wall so it wouldn't tip over in a sudden wake. Mr. Heater does not operate in any but a vertical position, but if very hot, it might melt or char something if it landed a certain way.

[SashasDad]

Thanks for the info. I'll opt for the catalytic heater. As for finding a different marina that has power, we're pretty limited. The closest water is 2 hours either direction. The nicer lakes are up north, but they're the ones without power. Oh well, 10 years till retirement and we can move to wetter climes.

[pokerrick1]

I'd retire earlier

Rick

[School House Steve]

Thanks Moe for the correction about the catalyitic Mr Heater. And to Night Sailor who shares my feelings and experience with this heater. Keeping in mind the air tight nature of our boats I always keep the the hatch part way open for ventilation when heating or cooking. I do not use this or any other type of hydro carbon type of combustion while sleeping expect as noted by John McDonough, a candle, wine and warm sleeping bag.

[PatrickS]

I've got a Wallas model 800 Mini Cooker w/model 220 blower lid. This unit burns kerosene and is positively vented to the outside of the Mac. It's a great hotplate cook top and the blower lid flips down over the hotplate to heat the Saloon when you're not cooking. I think I read in the owners manual the heater output for the single plate is 1200 watts. The Wallas stoves are very popular in the Northwestern US.
Terry C.

For those of you with Wallas systems, how is your exhaust/intake set up? Do you run it up to the deck, or do you have the through hull to the side? And where does it come out?

Does anyone have just the heater (i.e. 1300 or 1800)? If so, where/how is it installed?

Thanks,

Patrick

[Moe]

Hmm.. I agree about the Mr Heater - it's just ceramic. However, I use a Coleman ProCat heater (link) - that's truly a catalytic, I believe? Moe, what do you think?

It is a true catalytic according to Coleman. I respect the opinion of those who want heat, but here's how I feel about it...

If you feel you need to heat your boat, you are probably not dressing properly. Your clothing probably contains a good deal of, if not all cotton. For example, blue jeans, sweat shirt, even sweat pants. Even if you're wearing "fleece," it's likely to be mostly cotton. You are probably not wearing a base layer, aka long johns, and if you are, they are likely most or all cotton.

You don't need to heat the boat, you just need to dress properly for your environment. In fact, doing the former in lieu of the latter is a dangerous practice that may put your very survival at risk if the former fails. Our own bodies deplete oxygen in the cabin, replacing it with carbon dioxide and water vapor. That in itself requires ventilation, exhausting the latter and replacing them with cold oxygen-containing air. Sealing up the gap between the hatch board and sliding hatch cover is a bad idea. You really need more than just that.

Unvented combustion in the cabin, even perfect combustion that doesn't produce poisonous carbon monoxide, competes with us for oxygen, and produces even more carbon dioxide and water vapor, increasing the requirement for even more cold-air ventilation.

Adequately fed and hydrated, kept dry and sheltered from heat-robbing wind, your body produces all the heat it needs. The secret is not losing that needed heat.

Water conducts heat away from your body many times more than air. After ventilating it out of the cabin, the first step toward preventing that is a base layer of clothing that wicks water away from your body leaving an insulating blanket of air between the fibers. Cotton, particularly in undergarments, does just the opposite, holding more than its own weight in water right on your skin. Cotton kills! At the other extreme, there are high tech fabrics that excel here, but their price is high.

The best bang for the buck in the base layer is polypropylene--just don't ever put it in a clothes dryer! Air dry it. Duofold's midweight 230 series and 436 military fleece series are both 100% polypropylene. Don't forget polypro sock liners and beanie/helmet liner. A polypropylene base layer will make the biggest difference in your comfort level!

On top of the base layer add one or more layers of insulating fabric that will pull the moisture through the base layer, disperse it as water vapor into the surrounding air, and add more depth of insulation. However, don't forget there's no place for water in your clothing to go if humidity in the cabin is high. Inadequate ventilation contributes to that.

For centuries this mid-layer has been wool. It still insulates fairly well even when wet, but it is hydroscopic and holds about 1/3 its weight as water. Synthetic wool, such as Polar Fleece, is hydrophobic and dries much faster if accidentally soaked. Where it's a concern, Polar Fleece is more flammable than wool. Many hate wool for its "itchy" property, but good quality (and thus more expensive) Merino wool is much less so. Even the lower grades don't itch much with a good base layer. I won't debate the merits of each any further, but just note either is much better than cotton.

When outdoors/on-deck, you need a wind and waterproof outer layer that lets water vapor escape from inside it without letting water liquid soak into or through it. Here solutions range from expensive breathable waterproof fabrics such as Gore-Tex to more affordable rubberized or otherwise non-breathing waterproofed materials relying on vents for moisture release. Many of us have probably experienced poor rainwear that left us nearly as soaked under it as we'd be without it. It's not worth buying. Boots that keep your feet dry are also essential!

A boat operated in cold weather should be equipped with a complete set of backup base and mid-layer clothing for each crew member, as well as spare towels, all sealed in waterproof containers.

And when operated on cold water, a survival/immersion suit should be worn when in the cockpit. Muscles lock up and become useless quickly in cold water. A PFD is nothing more than a life insurance claim enabler. We've had the discussion here before more than once that you're probably not going to be able to bring an incapacitated adult aboard a Mac powersailer since they can't help you help them. You need control of your muscles to get yourself back aboard.