Electric Heater for Liveaboard in Boston

[JK n Smitty]

Originally Posted by CarinaPDX

In the winter in Boston an electric heater on medium is unlikely to keep the boat warm enough in the daytime, at least during the cold spells. That is what I use here in Portland, OR. When I wintered in Gothenburg, Sweden, I was running my diesel heater full time and at least one electric heater full time.

Remember, you must ventilate your boat: bringing cold dry air in from outside and exhausting warm moist air. Without substantial air flow the boat will become very damp inside. So you will use more heat than you might expect.

If you have the surface area then your Envi looks good. But if I read it right it only puts out 475W. I would expect you to need a total closer to 2kW, or even 3kW, on the cold days.

Greg

Hmm. I know about the need to ventilate and deal with moisture. I hadn't looked at the watts. Thanks for pointing that out.

[The Other Gary]

I use 400 watts in the head alone.

Ceramic plate wall heater on a wall thermostat.
It is mounted about 6 inches lower than my longest towels in the towel rack.
toasty warm towels after a hot shower is A1 on a freezing morning in January.

[shorebird]

3 people just died last week in Ontario using a propane heater in a house during a power outage. If you read the literature that comes with virtually all unvented propane heaters, it will usually say "not for use in confined space or indoors." Backup or otherwise, just not safe.

[JK n Smitty]

Originally Posted by shorebird

3 people just died last week in Ontario using a propane heater in a house during a power outage. If you read the literature that comes with virtually all unvented propane heaters, it will usually say "not for use in confined space or indoors." Backup or otherwise, just not safe.

Thank you for the concern.

[Tantalus]

Originally Posted by sailorchic34

Being a cheap sailor and an engineer, I converted a buddy lp heater to run off the large propane tank at low pressure (not as the manufacturer does with high pressure), mounted it to the bulkhead and then designed a flue, draft hood and vent flashing for it. Adding a vent hood, gets rid of the moisture and CO issue. I used 1-1/2" copper pipe, an 8 inch square non Teflon cooking pan and some basic fittings (from a salvage yard) for the vent hood and flue. Total cost, less then $200

It works surprisingly well.

Note that doing the above, voids all warranties and if installed incorrectly could cause fire and or death.

Sailorchic...please add me to the long line of guys on here who want to marry you

[Ryan H]

Bah, all you're friends had to do was knock on my Hull and they would've had a warm (albeit cramped) place to stay. It sounds like you'll be perfectly alright with what you're looking to do. My little boat did fine with one 1500 watt heater, a little propane unit just like yours mounted next to the hatch that I used for emergencies and to quickly warm the boat to extra toasty when I got home, and an electric blanket. The 1500watt heater was kept on low most of the winter except for the coldest days and then only when I was hanging out in the main cabin, and with the bulk adapter hose run to the tanks in the stern I went through about three and a half propane tanks this winter, and that's after getting fed up on a few of the God awful coldest days and cranking everything up to 90 degrees in the boat just to spit in winters eye. No problems with condensation on my boat yet (knock on teak).

Besides the heated blanket (which I really do recommend) how's your boat insulated? When I built mine up I covered the Hull in 1" foam insulation, glued in a foil radiant barrier over the insulation and slatted cedar strips over everything. It isn't that expensive, was easy to do, and came out looking pretty good. I also got my hands on a few thick felt blankets I toss over the companionway hatch during the nights as an extra layer of insulation and to cut down on drafts, you probably wouldn't have that problem as much if you're shrinkwrapping but I figured its worth mentioning.

Try to get you're hands on an ice eater off Craigslist if you can. They pop up a lot this time of year cheap, I know captains cove knocks off 10$ per ft for the winter season if you have your own.

Haha, My girlfriend just complained she's too hot and turned the heater down more. You'll be fine :-)

You coming to Captains Cove or Constitution?


Sent from my SGPT12 using Cruisers Sailing Forum mobile app

[Tantalus]

+10 on electric blanket. Don't leave home without one

[JK n Smitty]

Originally Posted by Ryan H

Bah, all you're friends had to do was knock on my Hull and they would've had a warm (albeit cramped) place to stay. It sounds like you'll be perfectly alright with what you're looking to do. My little boat did fine with one 1500 watt heater, a little propane unit just like yours mounted next to the hatch that I used for emergencies and to quickly warm the boat to extra toasty when I got home, and an electric blanket. The 1500watt heater was kept on low most of the winter except for the coldest days and then only when I was hanging out in the main cabin, and with the bulk adapter hose run to the tanks in the stern I went through about three and a half propane tanks this winter, and that's after getting fed up on a few of the God awful coldest days and cranking everything up to 90 degrees in the boat just to spit in winters eye. No problems with condensation on my boat yet (knock on teak).

Besides the heated blanket (which I really do recommend) how's your boat insulated? When I built mine up I covered the Hull in 1" foam insulation, glued in a foil radiant barrier over the insulation and slatted cedar strips over everything. It isn't that expensive, was easy to do, and came out looking pretty good. I also got my hands on a few thick felt blankets I toss over the companionway hatch during the nights as an extra layer of insulation and to cut down on drafts, you probably wouldn't have that problem as much if you're shrinkwrapping but I figured its worth mentioning.

Try to get you're hands on an ice eater off Craigslist if you can. They pop up a lot this time of year cheap, I know captains cove knocks off 10$ per ft for the winter season if you have your own.

Haha, My girlfriend just complained she's too hot and turned the heater down more. You'll be fine :-)

You coming to Captains Cove or Constitution?


Sent from my SGPT12 using Cruisers Sailing Forum mobile app

Thanks. This was a great reply.

We will most likely be at Constitution. My friends that were at Captains Cove last year are Tom and Nancy on their Freedom 30 Sunshine. Don't know if you remember them.

I was thinking the shrink wrap would help with some of the drafts but I also planned to add some insulation. Similar to what you have but I hadn't thought to add the cedar.

Thanks for the tip on the ice eater.

[Jsol]

Originally Posted by JK n Smitty

Thanks. This was a great reply.

We will most likely be at Constitution. My friends that were at Captains Cove last year are Tom and Nancy on their Freedom 30 Sunshine. Don't know if you remember them.

I was thinking the shrink wrap would help with some of the drafts but I also planned to add some insulation. Similar to what you have but I hadn't thought to add the cedar.

Thanks for the tip on the ice eater.

Jesse,
If you are considering wintering somewhere other than Hingham next season, consider BHSM, much cheaper than Constitution and has a live aboard community. If you have any interest PM me and I will provide you with the good and the bad...

[Dockhead]

Originally Posted by JK n Smitty

Glad you had so much to add.

I confess that I have sometimes been accused of being a grammar Nazi. But still . . .

[AfterHoursNLCT]

Originally Posted by The Other Gary

I use 400 watts in the head alone...

That's what I was thinking. How much heat are you going to get with 475 watts? ...LL

[rw58ph]

Basically you should work backwards from the dock amp power available and/or what the boat is wired for. The basic formula for converting watts to amps is: Amp X volts equal watts of watts/volts=amps. So if a heater is 1500 W is 12.5 amps, 900W is 7.5 amps. 600W is 5.0 amps and 400 is 3.3 amps. So if we assume you have 30 amps dock power and you use 10 amps for water heater, lights, misc that leaves you 20 amps for heat. So you can use a combination of heaters as long as they do not combine exceed 20 amps. You can stretch the 30 amps by adding timers to high amp items, like water heater to come on/off at a certain time of the day to allow more amps for heating at night.

When we first bought the Eagle we had 50 amps 120 volts which is not enough to heat a 58 ft boat in the Seattle area, so we installed a CAT catalytic propane vented thermostat controlled heater to heat the salon for 4 years. http://ventedcatheater.com/ Cast about 500 bucks and took me about 4 hours to install.

The electric hearer we permanently installed were Pic A Watt where you can set the watts/amps. You can buy them at Lowes for a couple hundred bucks, but portable might work also. What every heat source make sure its low in the boat as heat raises, and great a draft to draw the heat.

Anyway the limiting factor is probable going to be the dock electrical amp available and/or what the boat is wired for.

[JK n Smitty]

Originally Posted by rw58ph

Basically you should work backwards from the dock amp power available and/or what the boat is wired for. The basic formula for converting watts to amps is: Amp X volts equal watts of watts/volts=amps. So if a heater is 1500 W is 12.5 amps, 900W is 7.5 amps. 600W is 5.0 amps and 400 is 3.3 amps. So if we assume you have 30 amps dock power and you use 10 amps for water heater, lights, misc that leaves you 20 amps for heat. So you can use a combination of heaters as long as they do not combine exceed 20 amps. You can stretch the 30 amps by adding timers to high amp items, like water heater to come on/off at a certain time of the day to allow more amps for heating at night.

When we first bought the Eagle we had 50 amps 120 volts which is not enough to heat a 58 ft boat in the Seattle area, so we installed a CAT catalytic propane vented thermostat controlled heater to heat the salon for 4 years. http://ventedcatheater.com/ Cast about 500 bucks and took me about 4 hours to install.

The electric hearer we permanently installed were Pic A Watt where you can set the watts/amps. You can buy them at Lowes for a couple hundred bucks, but portable might work also. What every heat source make sure its low in the boat as heat raises, and great a draft to draw the heat.

Anyway the limiting factor is probable going to be the dock electrical amp available and/or what the boat is wired for.

Thanks. Someone else just recently pointed this out too. My single 30 amp shore power is definitely going to limit me. I will look at the link you sent. I think I may need to go with something like this.

[AfterHoursNLCT]

I added another 30 amp load center for just heat and A/C...

[Tim R.]

We installed a 12v diesel hydronic system so that we could extend our sailing season in comfort. It also allows us to heat our boat for days without shore power. The electricity was only out for a couple hours this year but the heater kept on running.

Considering your boat wiring as mentioned by rw58ph is paramount to installing safe and functional electric heaters. Too many boat fires caused just from owners over extending their boats wiring and not maintaining their shore power plugs properly.