Is there a such thing as a safe electric boat heater?

Nov 18, 2010
2,441
Catalina 310 Hingham, MA
So our house is under agreement and by the end of April we should be full time live aboards. We have owned our current boat for 3 years and have lived on her April through December all ready. We usually just use a small space heater and that keeps the boat plenty warm. But now that we will be full time I am trying to get some input on the heating system. We will be in a slip while we continue working to fill the cruising kitty and don't want to go through installing a diesel heater since we will only need to deal with one winter in New England before we leave to go cruising. So here is my plan. Please give me any input you have.

The boat is a Catalina 310 which has an open plan and is essentially one big cabin. There is a bulk head between the salon and forward birth but there is a door and a large window opening that are both always open. In the stern, there is also a bulkhead with a hatch that separates the rear birth from a mechanical area with the waterheater in it.

One thing I read that has been incorporated into our plan is that you are better off using multiple heaters on low rather than fewer or one heater on high. I also have a propane heater that is safe for indoor use that will be our backup incase we ever loose power. But from talking to people at the marina where we plan to stay they don't have that problem often. We do also plan to do a clear shrink wrap enclosure for the winter.

So here is my plan (see attached picture). Heater #1 the wall mounted panel heater. Based on the reviews and product literature, its a cool to the touch heater that puts out good heat and is safe to leave unattended. It has a thermal cut off for safety and no moving parts that could clog up with hair or dust. That would be the primary heat that would run 24/7. I have a good fan mounted in the open window on that bulk head that would push the heat generated into the forward area.

Heater #2 would be the Caframo 9206. The top step on our companion way stairs is open and this heater will fit there. This heater will be turned on when we come back to the boat and used to give a boast until we go to bed. It will most likely be shut off at night with just the Envi running through the night.

Heater #3 would be an electric space heater with a thermal cut off and knock over safety. That would be placed in a 2' x 2' opening in the bulkhead that separates the rear birth from the companion space. It would be used to keep the temperature in that area above freezing so that our water heater can remain in use during the winter. We currently just bypass and drain it as we get towards freezing temps.

OK, let's hear it. How bad of plan is this?

Thanks,

Jesse
 
Sep 25, 2008
7,336
Alden 50 Sarasota, Florida
Did you consider a #4 reverse cycle heat/AC?

Cost is greater but so is the value particularly if you head south
 
Sep 25, 2008
1,096
CS 30 Toronto
You are looking for disposable heater that once you headed south you won't need them (as much)?

Any infrared heater can start a fire if not carefull. I hate fan heater as they are noisy. Oil filled heater is the most quiet and won't make noise. I have 2 X750W oil filled and a WestMarine fan heater. Becareful with the current draw especially on high heat. 30A isn't that much when you add the hot water heater to the overall draw.
 
Feb 6, 1998
11,701
Canadian Sailcraft 36T Casco Bay, ME
Yes they can be used "safely" but some are safer than others. The little fan assisted ceramic ones are petty good, like the old Pelonis style, if they have tip over protection. The oil filled radiator style are perhaps the safest. Any of them need to be well secured and out of the way of combustibles. Anything with a glowing element should really be kept well out of range of anything combustible and personally I would not have a glowing-element heater on my own boat...

The BIG challenge is your shore power circuit. If you want to run three AC heaters even on low, you will need a second 30A service or to convert the vessel to 50A.... Running that much current do be sure you are NOT using "twist lock" shore power cords.....

Even three heaters run at 750W is over 20A. You will at least need a second 15A 120V outlet circuit too. A standard 30A cord should not be run at more than 21A, if you want to do it safely. Your water heater also has a BIG element in it, about 1250W or another 11.4A at 110V..... All three heaters at 750W, and the water heater kicks on....... hello melt down..:eek:.

 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Yes they can be used "safely" but some are safer than others. The little fan assisted ceramic ones are petty good, like the old Pelonis style, if they have tip over protection. The oil filled radiator style are perhaps the safest. Any of them need to be well secured and out of the way of combustibles. Anything with a glowing element should really be kept well out of range of anything combustible and personally I would not have a glowing-element heater on my own boat...

The BIG challenge is your shore power circuit. If you want to run three AC heaters even on low, you will need a second 30A service or to convert the vessel to 50A.... Running that much current do be sure you are NOT using "twist lock" shore power cords.....

Even three heaters run at 750W is over 20A. You will at least need a second 15A 120V outlet circuit too. A standard 30A cord should not be run at more than 21A, if you want to do it safely. Your water heater also has a BIG element in it, about 1250W or another 11.4A at 110V..... All three heaters at 750W, and the water heater kicks on....... hello melt down..:eek:.

MS,

Thanks a lot for adding to the discussion.

I had already planned to change to a Smart Plug this summer before we start using the heaters. I hadn't considered adding a second 30A service. This is definitely some new information I will have to carefully consider. I don't suppose there is a way to add this temporarily for one season?

The heater we currently use is the ceramic fan assisted style you mentioned. It works fine but we are usually out of the water the first week of December. I don't think that will be adequate for the rest of the winter.

Could you please offer your opinion on the oil-filled radiator style versus the cool-to-the-touch wall panel style like the Envi (http://www.eheat.com/)? (If you have one)

Thanks to everyone who responded.

Jesse
 
Nov 14, 2013
200
Catalina 50 Seattle
We have an oil-filled radiator at home and find that it's very powerful and its convection heat is very pleasant, while being safe with small children due to it's relatively low surface temperature and lack of any ignition source. The only knock I've heard against them for use on board is that if they corrode to the point of springing a leak, they can treat you to boiling oil. However, if you inspect them once a month or so, I imagine you'd get years of safe use out of one.
 

Tom J

.
Sep 30, 2008
2,319
Catalina 310 Quincy, MA
Just a suggestion, Jesse, if you heat the aft area where the water heater is, don't forget to block off the fresh air vent for the reefer condenser. Otherwise, you'll be trying to heat the whole Hingham Shipyard. :) Oh, and maybe the condenser heat will actually help keep the area warm.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
what about Hydronic (spelling?) heat Tim R has it on his boat and i haven't heard him say anything negative about it ........or you could get one of those ac unites with a heat strip like ocean breeze or ships air

regards

woody
 
Feb 6, 1998
11,701
Canadian Sailcraft 36T Casco Bay, ME
what about Hydronic (spelling?) heat Tim R has it on his boat and i haven't heard him say anything negative about it ........or you could get one of those ac unites with a heat strip like ocean breeze or ships air

regards

woody
You might fit an Espar or Webasto hydronic on a 310 but I can't think of anywhere you could fit the Hurricane Heater...

That electric wall hung unit looks decent. Just be sure it is a UL device. Lots of Chinese stuff flooding the market that has not been through much testing..
 
Jun 8, 2004
2,925
Catalina 320 Dana Point
My 320 only has a 10 amp circuit breaker on the panel for the cabin outlets circuit, I have to put the heater on low to run the coffee pot.