Portable, Temporary Underway Heater

[hellosailor]

I just got off the phone with Her Most Imperial Brittanic Majesty, who assures me that her subjects should refrain from calling water heaters "calorifiers" since the National Health wishes to reserve that term for the use of equipment which will make her subjects fatter. (With the end goal of making them fat and happy.)

Bearing that in mind, yes, what is called "hydronic heating" is just a water tank, heated by the engine, that extends in the form of hot water pipes into all compartments. Heat transfer fins and fans then blow the heat into the various compartments. Variations in the equipment and exact distribution are irrelevant to how the whole system works, as long as the engine can supply enough waste heat to get that water hot. And as long as your diesel engine has a thermostat, it should be up to the task. If there's a lot of water volume involved, it will take longer to heat up, the same way that a large hot water tank would take longer to heat up.
But the folks who make the heating systems should have the necessary specs on hand, i.e. which system can accommodate the number of linear feet of pipe you'll be running, the number of cubic feet of cabins you'll be trying to heat, the size of the engine that will be needed to fire the whole thing up.
Also consider that if you have the electric power, you can add electric mattress pads to help give the bunks an extra boost. Much simpler to install, as well.

[Bentwings]

A couple things. These “calorifiers” were a bit of a mystery to me. I honest to gosh thought these were something to cook with. Like a crock pot. They are probably the only thing I never looked up to see what they were. Often they were noted when talking about heaters and I just drifted off to heaters. Today I actually used the look up button when selecting like I was going to copy and paste. lol and behold these are nothing but a hot water heater. Yes you can use them for radiator heat too.

For the OP however, he wants a portable as he is going south and maybe will,never see really cold again. It’s been in the 30’s even in Florida however. When it is, it is shockingly cold to most not used to really cold weather. It was -15 F this morning here and even with the new boiler in the “ Hanoi Hilton” getto apt we live in it was only 64 deg F. Now that’s not brutally cold even in the summer but when you get up in the morning in your skivies from your nice warm bed and start looking for something to wear it is.

Your reverse flow AC is going to be working OT when it’s trying to pull heat out of 45-50 F water. If you can get 65 in the boat when it 45-50 outside you’ll be doing good.

My suggestion is to use the geny and a couple of milkhouse electric heaters. When you are done with them, they can be positioned so they “fall” overboard in 100 feet of water. They will be a nice home for sea life.LOL

Otherwise a streetrod car heater and suitable fan can be fitted using 5/8” heater hoses. As long as the motor runs 160+ there will be plenty of heat. If you put shutoff valves in the hoses you can just leave them hooked up Year around just like they are in your cars.

I plan on doing this first thing in the spring. My Westerbeke already has ports for this, all I need is plumbing and the heater. I can get access to the middle step of the salon stairs from my engine room.

Calorifier= cabin heater.

[john61ct]

portable

temporary

[john61ct]

calorifier = heat exchanger, usually water-to-water, sometimes steam

water-to-air exchanger is different

aka radiator, bus heater, heater core

[Bentwings]

Yeah, I know John, it’s below 0 here and going down hill. My dog and I have been out for the after noon walk and we are just getting warm again. ( up to 65 deg F) It’s better to sit here and tap on this keyboard, at least my fingers are staying warm and getting exercise.LOL

Now I can refer to my automatic “calorifier” in my antique 1994 Buick RoadMaster wagon. I can’t wait to try this on the Sat. car guys breakfast next week.
“ hey y’all, got a “calorifier” in your A Bone?”

Byron

[Scout 30]

Originally Posted by rbk

Been using the buddy heaters for years. Condensation and CO are not as big a problem as people think. Keep a CO alarm nearby, but in many years of use with a CO alarm within 3-5’ of the heaters (have gone through a few) I have never had it trip an alarm in enclosed spaces. Go with the buddy / big buddy and rig it to an external 20lb tank to avoid the build up of bottles. It could be used under way if strapped down but there is a tilt kill switch that can be too sensitive (more so on the little buddy) these also all have a thermocoupler with pilot light, if the light gets blown out it kills the gas, if the light goes out from lack of o2 or excess CO it kills the gas. These are quit safe even in enclosed spaces when used properly.

Well said & 2nd all of this information. That being said I have the Portable Buddy Heater & it works great.

[Montanan]

Originally Posted by boatman61

Humidity would be an issue.. you'd have running water in no time.
Something like this on the cabin sole would be better..
https://www.t7design.co.uk/products/...ab-heater.html

Exactly the issue of burning propane without a chimney to eliminate the products of combustion in an enclosed vessel. Lots of induced humidity and lots of water condensation on cold surfaces. And it will become clammy and stuffy as oxygen is depleted, CO2 increases and water vapor rises. The device has an Oxygen Depletion Sensor which if it works correctly would shut of the device before dangerous depletion of oxygen was derived.

During combustion propane's three-carbon alkane (3CH8) is added to five molecules of oxygen (O5). Creating 3 molecules of carbon dioxide (3CO2) and four molecules of water (4H2O).

Better to use a device that has a heat exchanger and a chimney to dispense the products of combustion out a chimney. A device with a fan will improve the heat exchange results.

[thinwater]

Originally Posted by jsanton

Fear of propane is a good thing. Its not instant death or wetness but its a dangerous move.

I’m totally surprised that noone has offered the best solution out there- the wheems and plath yacht lamp. I heat my hunter 356 with the large one. Id use 2 in a 51 ft vessel. I am in socal, so the heating needs arent as great but it’s not incredibly different since our ocean temps are about the same- mine are likely colder than yours.

Perhaps its not widely known how much heat they generate.

Theyre safe underway if you use the gimbal mount.

For my bedding i use a down comfortor- they heat up so quick when i get in bed.

You realize that we were seeing 0F a week ago and it is below freezing now. I suspect what you consider cold is higher than we set our thermostats in the winter. A few lamps would be a rounding error, probably a net loss compared to the draft required to keep them safe.


The OP needs real heat, not placebos.

[Bentwings]

While I don’t have experience with these, I have used Coleman kerosene lamps in the cold of northern Minn. They don’t heat much more than a small tent but they will give you enough light to read by. Your rear end will still be freezing. That I’ve done. I would not run either in boat.

We are talking raising and maintaining an uninsulated area some 300 sq ft 30-40 deg F, maybe more of each. We need heat not romantic atmosphere.

I’m not being a dork, they are cool looking devices.

A few weeks ago I was up in my boat protected from wind by the shrink wrap. I had some measurements to make and write down. It was about 15 F and my little dog crate heater of 750 watts with a fan was not enough to even keep the ballpoint pen warm enough to write with. I had to dig up a real,pencil,out of my tool box. My iPad shut down before I even got in the boat.

When you are out on the water and it’s 40 deg F with the wind blowing it’s COLD.

[Johnsteffey]

Panel truck heaters from a junk yard are self contained with 12v fan and condenser that circulates hot water from your main engine.
It can put out a tremendous amount of virtually free BTU’s while you are motoring.
Very simple to install with new heater hose and some 12v marine wire for the fan. I would add a variable fan switch. FYI

[hellosailor]

The OP is looking at a 51. A panel truck is rarely 20 feet bumper to bumper. Double those distances for the length of the heating loop, and you may find that a panel truck heater simply doesn't have enough flow to get the hot water moving in fifty feet of boat. Larger diameter hose (of a better type) and a booster pump may be required, unless you start ducting hot air, which means running ducts.

I vote for a nice snowmobile suit, and a quick trip south to where it is no longer needed.

[rbk]

Catching up there are a few things to mention:

Engine heaters(red dot, panel heaters?): watch adding too large or too many of these, they can take too much heat away from your engine and should be sized properly to allow you engine to run at proper temp.

Direct vent heater (double walled chimney or dedicated external combustion air): These are safe and produce heat but they actually allow accumulation of moisture in the cabin from breathing, cooking etc (this is why air tight houses require HRV’s to remove moisture and CO2 laden air) The benefit of drawing combustion air from the cabin draws cold air in (assuming proper ventilation of the cabin), lowering the rh of the cabin (RH is a function of temperature and pressure, an extreme example would be air with 100% rh @ -40’c when warmed to 20’c would have a rh of around 15%, same air, same water nothing added, nothing removed, look up pshycrometric chart for exact numbers if you’re interested) it seems counterintuitive drawing cold wet air into your cabin but once it warms it will hold more water vapour lowering the rh of the cabin air, using it for combustion then expel through the exhaust.

[gulfislandfred]

If you are motoring, and you have a motor heated hot water heater, you can get a couple of bus heaters, and plumb them into your hot water system temporarily. For the short time you're talking about, it may be cheaper to run your engine at a high idle (in gear. Might as well get some forward motion out of the deal) than to burn other fuel.


Your heat pump can also run when the motor is running, without running down your batteries.

[Dockhead]

Originally Posted by rbk

Catching up there are a few things to mention:

Engine heaters(red dot, panel heaters?): watch adding too large or too many of these, they can take too much heat away from your engine and should be sized properly to allow you engine to run at proper temp.

Direct vent heater (double walled chimney or dedicated external combustion air): These are safe and produce heat but they actually allow accumulation of moisture in the cabin from breathing, cooking etc (this is why air tight houses require HRV’s to remove moisture and CO2 laden air) The benefit of drawing combustion air from the cabin draws cold air in (assuming proper ventilation of the cabin), lowering the rh of the cabin (RH is a function of temperature and pressure, an extreme example would be air with 100% rh @ -40’c when warmed to 20’c would have a rh of around 15%, same air, same water nothing added, nothing removed, look up pshycrometric chart for exact numbers if you’re interested) it seems counterintuitive drawing cold wet air into your cabin but once it warms it will hold more water vapour lowering the rh of the cabin air, using it for combustion then expel through the exhaust.

Sure, but you have dorades don't you? Or some other cabin ventilation?

I don't know about other folks, but I leave my 6 large dorades open and working during the winter. I'm sure I lose a lot of heat through them, but you really must keep air moving in a boat, if you want a livable atmosphere, and don't get me started on mold . . .

So your direct vent heater wouldn't be any problem.

FWIW, my Eberspacher heater does draw combustion air from inside the hull volume, so pulls air through the cabin, but I don't think that in the grand scheme of things that moves the needle, especially not when the North wind is whistling through the dorade vents!

[zeehag]

had a portable heater once. when my generator burned -- yes flames..i tossed it. my engine makes a very warm interior of boat while underway. no issue.
i tossed the hot water heater upon purchase of boat. it was leaking so it went away.