How to Balance Power in Winter

[Jdornick]

Hello All,
We are from San Diego but are wintering in Seattle on our way north. This is our first time being in winter temperatures (30s & 40s) on the boat and we find ourselves constantly juggling power between all of our heaters- space heater in forward bedroom, space heater in master, space heater in engine room, radiator in salon and dehumidifier in salon. We are constantly turning one or two of them off to run other things like the microwave or oven. It’s a constant dance and a lot of times we’re popping breakers. Any tips or advice for us cold weather newbies on how best to manage our power and still stay warm?
Thanks as Always,

 

[Steppe]

Sounds like you are learning how to manage your shore power demands. If you are heading north to BC and southeast Alaska I would encourage you to invest in a diesel powered heater, either a forced air unit or go with a hydronic like Webasto.

Once you get past Campbell River the availability of 50 amp shore power becomes more scarce. Some marinas don't even have 30 amp power. The last time we were at Shearwater people in the dock were pissing about too many boats using "Y" adapters and taking up too many of the 30 amp sockets.

Going north you need to plan on many nights at anchor and not running a genset full time. Well planned diesel heat is the only way.

 

[psneeld]

For a boat that size, I strongly suggest a diesel heater system and a 50A 125/250V minimum electric shore power.

 

[Comodave]

I agree that you have the wrong type of heating. You need to mobe away from space heating. You can look at ways to conserve the heat you have inside the boat by insulating the boat as best you can. One place to start is the windows. Get some of the shrink type of clear plastic that goes on inside the windows.

 

[Retriever]

Do you have reverse cycle air conditioning? Mine are a lot more efficient in heat mode than space heaters. Unless we're using the 240v washer or dryer, we can run three zones of reverse cycle heat and still have enough overhead left over to not pop breakers when the microwave or hot water heater cycles on. Of course, that's on a 50A 240V shore power.

If we only have 120V shore power (30A or 50A) we use the hydronic furnace for heat and hot water.

 

[Jeff F]

You do get used to power juggling. It'll get you through this winter, but not optimal.

For this winter I'd suggest electric mattress pads and maybe blankets. Heat only the space you're living in. No need for ER heat. Chase down major drafts and seal them up. Consider sealing windows. Run the dehumidifier at night and the heater during the day. Watch your AC amp meter to understand the loads.

And yeah, you should start thinking about diesel heat. I put a diesel hot water system in my boat last year and it's made things very comfortable. I take it you don't have reverse cycle A/C?

 

[High Wire]

Do the space heaters have a LOW setting? Sometimes you can keep 3 going on LOW (500 watts) and use the microwave on a separate circuit. If everything is all on one outlet circuit there is no other choice but to kill the heaters.

 

[ghost]

If you are juggling that much, that often, you are likely running a very high duty cycle on your cord set. If that cord set is a Marinco 30 amp in other than new/perfect condition, it’s going to melt and risk a fire.

Diesel heat, upgrade your cord set and make sure your electrical is in perfect condition.

 

[OldDan1943]

I am a 2 leg 30amp boat. One leg is devoted to the A/C.
The other leg, house.
I have electric stove, microwave, electric hot water heater when at the dock. Underway, the main engine heats the water.
I was popping the house breaker when cooking and hot water heater kicks in. I solved most of the problems by installing an AMP meter in the galley area. I watch it as I cook. First off is the hot water heater. I do have the ability to put the microwave on an inverter but it sucks down the 2X4D rapidly. I guess I could bring online the 3rd 4D but that is devoted to the engine and considered sacred.
The key "take away" is the amp meter in the galley area. It saves going to the pilot house to reset breakers and/or the shore power breakers.
Per electric heaters. Turn on the 2 factory installed heaters, no room for anything else.
Remember, you have lots of heat in the ER so opening the access deck plates to the ER will free a lot of heat, if necessary.
Also, I have a number of compartment 12vt fans to equalize the heat or AC temp. They run 24hrs/day. I consider them "expendable" and change them as necessary.
On a 30amp boat it is always watching the amp meter and adjusting the load.

 

[jungpeter]

Hi Jdornick,

From your original post, it sounds like you're living aboard 24/7 in the Seattle area this winter, in the hopes of venturing further north sometime soon? And not just preparing the boat to winter over, and retreating to dry land?

Where are you moored? What is the availability of shore power on your dock? What is the 110/240VAC setup on your boat? Have you conducted an energy budget, to see where you're using up your shore power? Do you have adequate instrumentation to actually monitor AC current used aboard? You may want to get a marine electrician aboard to help you with some of this stuff, as well as assess how well your boat is set up to enable significant shore power to be used safely aboard.

Your boat will sit in an approximately 45 degree infinite heat sink full-time. So, in my opinion, engine room heat is not necessary to protect your powerplant and other engine room infrastructure while you're dockside. Nothing will be damaged from freezing weather, even during the (few) really cold days in the Seattle area. And although this heat will radiate and convect upwards into your living spaces to some extent, much of it escapes through the hull sides and bottom, and it's essentially wasted heat energy that can be applied to your living spaces. Turning off your engine room heat will reduce your AC power demands.

In addition, unless your boat is sealed 100% from outside air (and that includes your engine room vents, cowl vents, anchor lockers, lazarette hatches, door seals, overhead hatch seals, etc.), your dehumidifier will simply attempt to dehumidify Puget Sound, at the cost of needless AC power. Even if you live aboard, interior temperature maintained slightly above ambient in your living spaces, coupled with adequate ventilation, should prove sufficient to keep condensation (and subsequent mold and mildew) at bay. Moving warm air around and ultimately out of the boat with low-power fans does wonders to promote comfort and energy conservation.

As previously mentioned, closing up unused parts of the boat (the forward head and stateroom(s) for instance), and leaving them unheated, will save you additional AC power. As will point-of-contact heating sources like electric blankets. The smaller the volume you attempt to keep warm, the easier it will be. I second other previously-mentioned ideas such as insulating those big, undoubtedly single-pane windows with an insulated window treatment which will reduce heat loss, thus reducing your need for interior heat.

And yes, most folks here in the PNW rely on diesel heat, either conductively via hydronics in the floors, or convectively via forced air. Much less 110VAC power required to keep a diesel heater at full chat. Absent that luxury, you may well have to load-shed to stay comfortable.

There are many 24/7 liveaboards in the Seattle area, so it certainly can be done. But not without an adjustment to lifestyle and living arrangements, which I'm sure you've figured out by now, aren't like SoCal!

Regards,

Pete

 

[tiltrider1]

It takes about 48,000 btu’s to heat a 52’ boat in Seattle. Heat pumps take about 39 amps to make this much heat. Resistance heaters (space heaters) make about 5.000 btu’s out of 1500 watts. This comes to 115 amps o make 48,000 btu’s. This means even if you have 50a 125/250v power, you do not have enough power. Diesel systems take less than 5 amps to make 48,000 btu’s (and some diesel).

Now on many days you don’t need 48,000 btu’s. So some people get by with less and when we get the really cold snaps they wear a lot of clothes and complain about being cold.

 

[Porgy]

Unless I missed it, are you planning to stay up there for some long period of time? If so, diesel heat makes sense. If not, that would be a large expense for a season or two. Installed price for 50k BTU Hurricane heater might run in the neighborhood of $20,000.

When I had to fiddle with our diesel heater, I brought in another 30A shore cord through a port and ran an electric heater off that (caveats about extension cord and adapter ampacity.) There was much less house amperage management needed.

We used a dehumidifier for a couple winters but found that having fans run 24/7 in each cabin and leaving the highest hatch open a crack worked as well. I would not hermetically seal the boat. However, outside window shade covers typically used to keep the sun out work well at keeping condensation off the inside of windows.

 

[catalinajack]

As jungpeter said, it is wholly unnecessary to heat your engine room. We winter in Maryland where we sometimes get ice as deep as a few inches. Three winters ago, we had a one-week stretch when the overnight temps dipped into the single digits yet the engine room never dropped below 35 degrees. The water bath in which the boat sits prevented it from doing so. Your water temp is 45 degrees. We would love 45 degrees as it gives more heat when using our reverse cycle. Right now the water temp here is about 40 degrees.

 

[tiltrider1]

Catalinajack is correct if you are moored in the salt water. If you are moored on lake Union then you need to be aware of the lake temperature. It can drop down to 30 degrees but that is very rare and I don’t see that as likely this year.

 

[ksanders]

It takes about 48,000 btu’s to heat a 52’ boat in Seattle. Heat pumps take about 39 amps to make this much heat. Resistance heaters (space heaters) make about 5.000 btu’s out of 1500 watts. This comes to 115 amps o make 48,000 btu’s. This means even if you have 50a 125/250v power, you do not have enough power. Diesel systems take less than 5 amps to make 48,000 btu’s (and some diesel).

Now on many days you don’t need 48,000 btu’s. So some people get by with less and when we get the really cold snaps they wear a lot of clothes and complain about being cold.

Thats a really good explanation from a Seattle Area Liveaboard!

I concurr on the BTU needs pretty closely. We have a 47' boat in pretty close to Seattle temperatures, only about 10 degrees colder.

On our boat it takes all of the 30,000 BTU of diesel heating capacity we have to keep the boat at 65 degrees throughout.

When it dips down to the low 20's and the north wind comes up I fire up the generator and run our several built in electric heaters as we'll. This provides heat to the engine space and offloads the shore power connections.

 

[Jdornick]

Thank you all for all of your thoughtful and wise suggestions and perspective. We will be working on it ASAP.

 

[rsn48]

You are doing all the right things, and the right thing is popping the circuit breakers. I am on a 15 amp moorage, not my choice. So for me to balance heating, refrigerator, and things like tv and microwave is to turn this off to use that. Make sure that is off while I do this. I have popped the main circuit breaker for my finger on the dock going on 7 times now. Its a good discipline to learn how various items affect the electrical flow.

My buddy just bought a 1990 Nordic Tug 32. I told him to spend some nights on it at the marina, especially cold nights so he can pop some circuits and learn his boat, he's on 15 amps as well.

 

[Circumnavigator]

It takes about 48,000 btu’s to heat a 52’ boat in Seattle. .

I'd agree with that if it read "...about 48,000 btu’s to heat a 52’ production boat..."



The required heat depends a lot on insulation and windows. Most production boats are poorly insulated or have none at all. Fintry is R13 or more everywhere except the engine room, so our biggest heat loss is from the saloon and wheelhouse windows. We heat Fintry to 70F in weather down to zero F in Boston with a 50,000 BTU diesel fired boiler. Since surface area varies with the square of length, we have more than twice the surface area of a 52' boat and zero F is the record low (from 1950) at SeaTac.


Jim

 

[Cruising Sea Venture]

Welcome to the North. The cruising will only get better the further north you go. We are currently wintering / cruising in SE Alaska and it is a bit cold - today the high will be about 27 degrees, and the low tonight around 10 degrees.

While we have 50amp / 240 Volt shore power when connected with 3 reverse cycle Cruise Aire Units, we primarily use our diesel forced air furnace to heat the boat and it does great. It uses very little 12V power and about 1 to 1.5 gallons of diesel per 24 hours. Without a diesel fueled heat you will continually be playing the power dance when connected or the genset is running, and at anchor you will be chilly in the summer. A lot will depend on the weather this coming summer. In 2018 in Alaska we hardly ever saw a cloud, with highs in the 70's often enough we rarely had the heat on, except to take the chill off in the morning. This last summer, 2020, was a whole lot of wind and rain and cool temperatures - rarely did we see above 70 degrees. We never turned the furnace off all summer. Our furnace install was pretty easy and straight forward, and well worth the effort. Now would be time to take on the project if you are inclined. Once in Alaska you will find yourself ordering parts from Seattle (most likely Sure Marine) and waiting and waiting for them to arrive. (Amazon Prime takes 3-4 weeks).

In April we are headed further north to Prince William Sound before making a U-Turn and heading south again. Best of luck and hopefully we will get a chance to cross paths in 2021.

All the best,
Jim and Rosy Addington
M/V Sea Venture
www.CruisingSeaVenture.com

 

[Salish Nomad]

I would definitely talk to Sure Marine about a diesel furnace. There may be a boat show promo price running at this time.

 

[Crids54]

Dehumidifier is a must.

The dehumidifier is the key to comfort for winter liveaboards. Dry air is warmer air, also the heated mattress pad. Electric heat is more efficient than diesel when connected to shore power, less moving parts. That said, one 30 amp service won't cut it; you need 50 amps or ad a second 30 amp. The Webasco hydronic diesel heat system is the best way to go overall. Sure Marine in Seattle is the place to go for Webasco, https://www.suremarineservice.com/Heat/Webasto-Diesel-Heaters/

I have been living onboard in Portland OR for years. These things make the difference.
True North
43' Gulfstar

 

[Trawlerman]

I think you have had the best advice already. Go for the diesel heater, they are small, pretty trouble free, and great heat. Also, if you don't have it already, get a 50 amp 125/250 shore-power supply. A lot of boaters I have met don't realize that going from two 30 amp shorepower cords to one 50 amp shorepower cord takes them from a total of 2 x 30 = 60 amps @ 125 vac from two cords up to 2 x 50 amps = 100 amps @ 125 vac, a very substantial increase in capability. Our 50' marine trader uses reverse cycle heat and copes well down to about 14 deg. F without the need for space heater supplement.

 

[catalinajack]

Not all winter live aboards require a dehumidifier. We are just south of Annapolis. As I write, the relative humidity is 39% on board. We do not have condensation so no need of a dehumidifier. Every boat, every situation is different. We cook with electric so we do not have propane that adds to moisture inside the boat.

The dehumidifier is the key to comfort for winter liveaboards. Dry air is warmer air, also the heated mattress pad. Electric heat is more efficient than diesel when connected to shore power, less moving parts. That said, one 30 amp service won't cut it; you need 50 amps or ad a second 30 amp. The Webasco hydronic diesel heat system is the best way to go overall. Sure Marine in Seattle is the place to go for Webasco, https://www.suremarineservice.com/Heat/Webasto-Diesel-Heaters/

I have been living onboard in Portland OR for years. These things make the difference.
True North
43' Gulfstar

 

[Moonfish]

Before we installed our Wallas forced air diesel heater we referred to the constant turning on/off of electric heaters/devices the "30-amp dance".

Echoing what others have said, 50-amps (or a second 30) would be a good move in addition to having a diesel heat source.

 

[EngNate]

From a full time liveaboard on the central coast - insulate! Window film is a low hanging fruit, will save more BTUs per $ and hr spent than anything you do. Further insulating is a future project, takes lots of time and a fair bit of $. I spent close to $1000 US and well over 100 hours on my 31' and it still isn't complete, but the difference is huge. In our coldest so far this year, about 22F, I can maintain comfort on electric only with a 20A/120V service. Diesel heat, yes, especially as the boat gets bigger and the shore power doesn't, but heating with fuel in BC will cost you about 35% more than metered electric.

A tip with the film - you have to use masking tape. It doesn't matter what brand you get, the double side tape provided is only good for holding the film in place while it is trimmed and taped. Especially with metal frames you have to dry and warm the surface immediately before applying tape in cold weather. Clean the glass and apply anti-fog for clear view. Once you shrink the wrinkles out with a heater it's clear as glass.

 

[OldDan1943]

Before we installed our Wallas forced air diesel heater we referred to the constant turning on/off of electric heaters/devices the "30-amp dance".

I thought I came up with that '30 amp dance' I do that dance a lot in my galley, while cooking. Helps to have an amp meter in the galley too.

If you have 2 30 amp services to the boat a lot depends on how they are wired.
I have 2 30 amp services into my boat. One leg is devoted to the 2 A/Cs and the other leg is devoted to the 'house' usage.

On my N46, I had 2 50 amp services to the boat. One leg was for the 3 A/Cs the other leg was devoted to 'house' usage

Sooooo, it does not matter if you have 2 30amp services or 2 50 services. It all depends on how they are wired to what load.

On my current AT, I have 2 installed electric heaters. They are fed from the 'house'. Turn them on and there is nothing left on the 30 amp house leg. I also have a ceramic portable heater I will supplement the reverse cycle A/Cs, saving the installed resistance heaters for ......

 

[rslifkin]

I thought I came up with that '30 amp dance' I do that dance a lot in my galley, while cooking. Helps to have an amp meter in the galley too.

If you have 2 30 amp services to the boat a lot depends on how they are wired.
I have 2 30 amp services into my boat. One leg is devoted to the 2 A/Cs and the other leg is devoted to the 'house' usage.

On my N46, I had 2 50 amp services to the boat. One leg was for the 3 A/Cs the other leg was devoted to 'house' usage

Sooooo, it does not matter if you have 2 30amp services or 2 50 services. It all depends on how they are wired to what load.

On my current AT, I have 2 installed electric heaters. They are fed from the 'house'. Turn them on and there is nothing left on the 30 amp house leg. I also have a ceramic portable heater I will supplement the reverse cycle A/Cs, saving the installed resistance heaters for ......

I'd personally look to move those electric heaters to the A/C leg, figuring you're not likely to be using both at the same time.



In my case, with 2x 50A legs, I've got all 3 A/Cs plus the microwave on one leg, everything else on the other. Generally that works out just fine.

 

[Scottwb96]

Not sure if anyone else mentioned it... But, there's a thread on here about using the "knock-off" "Cheap Chinese Heaters"... I am actually debating on that for the flybridge area. I prefer to drive from up there, even if it's in less than desirable conditions...

Here's the link to that thread...

https://www.trawlerforum.com/forums/s30/chinese-diesel-heater-54446.html

 

[OldDan1943]

Hmmmm, move the microwave to the A/C leg. I will have to look into that. Thanks for the suggestion.

 

[Sealife]

Some more info:
https://downeastboatforum.com/threa...e-have-any-experience-with-these-units.33629/