Fellow liveaboards - any tips for winter insulation?

[gettinthere]

There is a Y cable available for that 50 amp plug to give two 30 amp outputs. Three sources of 20 amps each (derated) would make for a pretty toasty boat.

Consider running the exterior shrinkwrap down as close to the water as you can get. Drawstring the bottom close to the hull but put standoffs above that to keep the wrap out away from the hull to create a barrier. Use swim noodles, styrofoam cups, plastic cups, tennis balls, etc.

 

[limbodog]

The second video is interesting. They used EVA foam, which I'm very familiar with. It's good stuff. Tho' it is also noteworthy that they said it's not so much about keeping the boat warm, but rather keeping the condensation from touching their stuff. I have to think the way it works is by preventing the water vapor in the air from touching a cold enough surface to condense, but that means insulating. So why wouldn't that help keep the boat warm?

EVA is a lot cleaner to cut than the polystyrene, plus you can easily shape it with a heat gun and some judicious cuts. It's a bit less insulating than the polystyrene boards, but not by overmuch. Tho' it's about 2-3 times as expensive too.

I hadn't heard of people permanently installing EVA on boats for insulation before tho'. If that's truly an option, and isn't going to foster mildew between the foam and the glass, then I will definitely be doing that.. tho' perhaps not this fall. It's also nice that EVA comes in a variety of colors rather than just pink.

I've already picked up a decent quantity of polystyrene, so I may use that for my ceilings (if I can figure out how to hold it up) and get some EVA for my hull for a long term solution. Will have to cut the fuzzy liner they glued in and scrape that out, but I think it'll ultimately be worth it.

Thank you for the videos

 

[limbodog]

Consider running the exterior shrinkwrap down as close to the water as you can get. Drawstring the bottom close to the hull but put standoffs above that to keep the wrap out away from the hull to create a barrier. Use swim noodles, styrofoam cups, plastic cups, tennis balls, etc.

Now that's a new one to me. I haven't seen anyone do that out of the 100 liveaboards wrapped up at my marina. I'm not going to be the one doing the wrapping, but that shouldn't prevent me wrong putting some spacers between the wrap and the hull to make an air gap. I think I can get some cheap pool noods at the local dollar store type place.

 

[TomY]

I haven't lived aboard in a cold climate like Boston, but having experience with building design and heating in New England, I'd be more concerned with more than ample heat supply than insulation on a boat.

A boat is a small space but a difficult dwelling to make comfortable in cold weather. Moisture in any smallish space is the difficult part to staying comfortable. It's not too practical to install an air exchanger in a boat so I think you'll have to supply an adequate supply of fresh air.

The best heat source would be ample electric (because of no exhaust but will require heavy cables, circuits), or a fueled burner that had it's own air supply and exhaust to the outside. There are plenty of small units (Propane, K1) for land dwellings but I can't think of one that would be an easy fit on a boat. I'm thinking (air heater) a minimum of 20K BTU output that moves enough air to move through the boat, slowly so it's comfortable to cover the heat loss.

Again, I'd err on the side of overheating the interior and supply some outside air. That - I believe - would keep moisture levels the lowest to stay more comfortable. A big enough unit that could bring the boat up to temperature in not too long a time so you don't have to run it very high when you're not there.

Where exactly on Boston harbor is the liveaboard marina? I was on the water last weekend and didn't see where I thought it might be.

 

[limbodog]

Where exactly on Boston harbor is the liveaboard marina? I was on the water last weekend and didn't see where I thought it might be.

Charlestown. Constitution Marina is a big liveaboard community.

 

[sailme88]

So you've got shore power.. Using electric space heaters is a waste. Were I in your position I'd look to invest $750. for a heat pump. It won't tax your power supply and will heat to about minus 15 and cool until its 125. You'd need to run a feed and return. Without damaging anything, a possible route would be to make a dummy hatch board to fit either a sill fit or better a side fit. Check Daikin, Fujutsu and Pioneer. Mitsubishi is way over priced. A small system is all you should need. Something to bear in mind. The outside unit has a fan. This means it creates torque. Also some vibration. If you could temporally mount it on the float/dock that you are tied to it would be quieter.

 

[limbodog]

So you've got shore power.. Using electric space heaters is a waste. Were I in your position I'd look to invest $750. for a heat pump. It won't tax your power supply and will heat to about minus 15 and cool until its 125. You'd need to run a feed and return. Without damaging anything, a possible route would be to make a dummy hatch board to fit either a sill fit or better a side fit. Check Daikin, Fujutsu and Pioneer. Mitsubishi is way over priced. A small system is all you should need. Something to bear in mind. The outside unit has a fan. This means it creates torque. Also some vibration. If you could temporally mount it on the float/dock that you are tied to it would be quieter.

I'm not 100% clear on what you're describing. Do you have any pics of a setup like this anywhere?

 

[Jim26m]

This is what he's talking about if I understand him. There is a tubing and power umbilical that connects the two components. You can get different indoor units to suit different mounting arrangements.

Probably would not be my first choice based on what you appear to be doing. These are not cheap, plus, the colder it gets outside, the lower the heating capacity. Can you do it with these? Probably, but might not meet your budget. On the plus side, they are very efficient when the weather is moderately cold.

Several folks have recommended ventilation to prevent condensation. This is the best way to reduce interior humidity - better than your dehumidifier when it's cold outside.

The right way to go at this is to calculate your required heat load and size your heating units to meet the load. You have to include heating any vent air in your load calc, if you choose to use ventilation.

Like several others, I'm not sure how much hull insulation you can practically accomplish. I would insulate the interior using products that won't contribute to rapid flame spread or smoke development. I would heat and vent the cabin and circulate cabin air through the bilge and exhaust or relieve from the bilge to outside. In other words, you bring fresh air in through a heater that blows in the cabin. Install a bilge blower that pulls cabin air in and blows into the bilge. Then, verify that you have a path for the bilge air to exit.

Again, insulate the interior to the extent you can, then get enough heat to meet the conditions you want to maintain. Decide what energy source you want to use. If this has limitations, you may have to increase your insulation to allow you to meet your desired interior conditions. This iterative process is best done on paper. Working it out through trial and error can get expensive and frustrating.

If you do this correctly, you will have an uncomfortably dry boat. But, if you don't want condensation, that's going to be part of it. Maybe you can stand low humidity better than I can. When it gets under 50% rh, I start getting chapped lips and dry skin. Of course, where I live, you need gills to breath the air...

If you tent the boat, use care when using diesel or other combustion heating.

It's not rocket science, but it works better when it's appropriately designed.

 

[limbodog]

On my marina's facebook group, it was suggested I take the foam board I have and lay it on the deck and then toss blankets over it. (I used just blankets last year) This would be once I have the plastic up, of course. The blankets will keep the foam in place and may help insulate. At the minimum, I'll probably do the v-berth where I sleep.

For whatever reason, condensation wasn't too bad last winter. Maybe because I kept it barely warm enough to sustain life.
I've been reading more on EVA foam options. It's considered "non-flammable" by default, but it can be made with additional anti-smoke anti-flame ingredients to make it even safer. I'm liking EVA as an option, it's just going to be really hard to find a company that will sell me amounts as small as I want. (Monmouth rubber Monmouth Rubber & Plastics | Closed Cell Sponge Foam Manufacturer requires a minimum $750 order, which is a good deal more than I want, for example.)

I'm going to try to get my diesel heater working, but I'll only be using it while I'm awake. Even with the alarms, I don't want to be inhaling fumes while sleeping. So electric is still going to be my go-to for overnight anything.

As for the heat pump, I'd say the lowest temp I would expect to encounter could be about 0ºF. We had that a couple years ago here, albeit briefly. Typically most nights will be in the teens or 20s Fahrenheit. I don't know how well they work at those temps. I'm also not sure how much space they need both above and belowdeck. Sounds like I'd need to have a hatch open with a couple hoses running through, yes? And I don't know what the interior unit would be like as all the pics I find just show the exterior unit, which isn't small. Not that that's a deal breaker. I could mount it over my salon if it made sense to do so. I just don't know enough about these units to know.

 

[TomY]

What wattage and how many electric heaters did you have last year? It would likely take 3 or 4 electric heaters to put out a btu equivalent that I'd want as a minimum. Even 1500 watt heaters each require a separate 120V circuit. How many circuits are available to you?

I've used these 2000 watt fan heaters with good results. Not portable though and they use a 220 15 amp circuit. 3 would be close to 20,000 btu/ hr. As well as a thermostat, they have an hour timer that shuts it down at the preset time. They are less than 200/ea.

We heat our house partly with a heat pump here in Maine. We love it! I've installed several in clients properties. I think they would be too costly and complicated especially for a seasonal temporary set up on a boat.

With shrink wrap cover I think it just becomes too dangerous to use a combustion heater. Otherwise I might go for a space type heater in propane, like Rinnai sells. As long as you had a safe set up for outside intake and combustion lines, they would give you a dry ample heat source beyond what diesel boat heater outputs.

 

[limbodog]

I've got a 50a and a 30a, and a splitter for the 50 if needed. I don't really want to add more heaters. I'd rather just bundle up more than go above a $300 electric bill for a month. That's why I'm looking to insulate more. Make my heat stretch further.
I'm meeting a neighbor tonight who insulated the heck out of his boat and was very successful at reducing his power consumption. Hopefully he'll have tips on how to go about.

 

[sailme88]

The heat pumps are very efficient. The only use electricity, so no fumes or vapors. The electricity they use does not make the heat, they squeeze it out of the air. As earlier stated they will provide heat when the outside air temp is (-) minus 15 degrees. Yes, you do need to run lines. Only the converter would be inside. This looks like 1'x 3' box. Research Pioneer Mini-split $728.00 complete and that is 12,000 BTUs.

 

[sailme88]

Just saw the $300 month elec comment. I heat an entire 2800sq ft house on heat pumps. About $200 per month. Oil to do the same is about $325.+ We maintain 74degrees. year round.. and the system de-humidifies too.

 

[Jim26m]

Scratched a few numbers on a napkin. You may need around 40,000 btu/hr capacity to heat the boat to 65 deg F when it's 0 outside - WITH NO INSULATION. If you insulate the interior, and don't take any other precautions, the annular space between the hull and the interior will get so cold that all of your plumbing in the bilge MAY freeze. So proceed carefully with insulation projects.

If you try to make it comfortable with electric strip heat, it will be expensive to operate when it's really cold outside (which you noted - without actually making it comfortable).

Rough calc done quick. Take with a box of salt...

I'd be anxious to hear what your neighbor tells you regarding his approach.

 

[Jim26m]

Typical cabin heaters appear to max out around 20,000 btu/hr, so I assume the normal approach is to heat the main cabin area and let the rest of the spaces float at various lower temperatures.

RV ducted propane heaters will give you up to 35,000 btu/hr, which is the napkin calc number I came up with for your boat, but would require adaptation for safe mounting, unless you've got a vertical exterior wall that needs a hole in it... Plus, you would be baby-sitting a propane system.

Without really getting a handle on your "gotta-haves" vs "would-be-nice-to-haves", its tough to advise much further. Suffice it to say that you have a 40 ft x 13 ft poorly insulated, likely high-infiltration house to heat in a 0 deg F, windy environment. It's going to take a good bit of energy to pull it off, or a lot of envelope modification.
Insulating the cabin roof is a good idea. If there is no snow, or ice, the roof could account for a significant percentage of your heating load. Infiltration is a big issue, that I can't estimate without investigation, so plug up the leaks and only ventilate using heated air.

At low temps, the actual COP for heat pumps may drop to near 1 (approximately same as strip heat). However, for the months it's not at 0 deg F, the heat pumps would be gaining you 2 or 3 times the heating efficiency of strip heat. You will get significantly higher efficiency at milder temps (and ac to boot). Looking at first cost and operating costs, heat pumps of some form might be a viable alternative - if strip heat was your only other option. I know it seems I'm crawfishing on the heat pumps, but better than strip heat if your using it a lot.

Again, I'm making a lot of assumptions on construction details of a boat I've never seen, so - grain of salt...

Good luck. Hope you can find a solution that works for you.

 

[dLj]

I've always wanted to have one of these heaters in a boat. Years ago, I was on an old wooden boat that had the cook stove version in it, but I only sailed during the summer so we never fired it up... It likely isn't what you want/need But I can't resist throwing it in here...

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dj

 

[limbodog]

Scratched a few numbers on a napkin. You may need around 40,000 btu/hr capacity to heat the boat to 65 deg F when it's 0 outside - WITH NO INSULATION. If you insulate the interior, and don't take any other precautions, the annular space between the hull and the interior will get so cold that all of your plumbing in the bilge MAY freeze. So proceed carefully with insulation projects.

If you try to make it comfortable with electric strip heat, it will be expensive to operate when it's really cold outside (which you noted - without actually making it comfortable).

Rough calc done quick. Take with a box of salt...

I'd be anxious to hear what your neighbor tells you regarding his approach.

Some good info, and thank you for the math!

First, I met with my neighbor and while his boat *was* very toasty, unfortunately he did exactly what everyone has told me not to do. He insulated all his exposed interior hull with polystyrene foam board. I told him it was combustable and he was unaware. Not sure if that's going to make him redo it, but at least he knows. He also did a couple of his cabinets with pipe insulation. He used pipe insulation that was aluminized, if that's a word, on one side, folded it over so the fiberglass batting was completely covered, and taped it closed and stuffed it into the curved spaces. At least that part isn't flammable. But it also does nothing to prevent condensing behind it. So while his setup was very effective, the flammability and water intrusion both seemed problematic to me.

I also want to point out that I will be getting the boat wrapped. So mild wind won't be a problem in a few weeks. But yes, I've got a number of obvious gaps letting my heat out into the greenhouse. Most obvious is my companionway sliding hatch which could probably let in a determined hamster. I have been brainstorming ways to put insulation on top of it that would stay in place when opening/closing the hatch. Maybe putting an elastic on it to the mast so it's always pulled taut when I close the hatch from below? And I'm thinking I could sandwich some foam between the slider and the wooden hatch panels to block up the air leak. Maybe tape foam to the wood as well, I never bother removing it as it is easy enough to step over.

I'm interested in the heat pumps, but I really wish I could see how someone had set one up in a sailboat somewhere. All the videos I can find either show them in houses, or on a table so you can see the parts. I'm having a hard time thinking of how to set one up, and I don't know anyplace to go see one in person to get a feel for what would be involved. If it's as easy as running a hose and a wire through a porthole and setting the blower (I assume) on a flat surface then I could probably work with it just fine. I suppose I also need to look up tech specs to get a feel for what it delivers. I don't think it's meant to be a year-round solution as I can't imagine having the condenser above deck when under way. Right?

Right now I'm trying to find a company that will sell me a relatively small order of EVA foam with additional anti-fire/smoke treatment to permanently affix to my interior hull behind and above my shelving.

I'm not sure what you meant about freezing my bilge tho'. Maybe you mean if I insulate the floor too well so the bilge gets none of the heat I'm putting into the cabin?

 

[Jim26m]

Yes. If you insulate your cabin well, there is a possibility that your potable water piping/tankage could freeze. No biggie, just something to keep in mind as you're working through this.

A marine water source heat pump uses seawater in lieu of an air coil as the heat source/sink. They are pricey, but are meant to be installed on a boat and would be a much neater install than the mini splits - as far as presence on deck. On the down side, you'll need through hull access and a water pump. If you don't mind the look of the air side sections mounted on deck, the mini splits would likely do the job - if you can power enough of them. Mount the outdoor section on deck and the indoor section on a wall, ceiling, or in a compartment (you'll need to buy an appropriate indoor section for your application). I have seen mini splits permanently mounted on motor yachts and tugs. Don't think I've seen one on a sailboat, but you might be able to permanently mount it where it wouldn't be too bad. Again, can't see what I'm advising on, so...

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If your marina would tolerate it, you could put a package unit on the dock and duct supply and return air to your boat through ports.

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Did you happen to ask what heating capacity your buddy was using to heat his boat? If so, what temperature was he able to hold at zero degrees? If you have a lot of wood in your interior, it could make a difference in the capacity requirement. I assumed most of your interior was fiberglass (basically offering minimal insulation value).

Polystyrene definitely generates some noxious smoke when exposed to fire. In any case, in a boat, you better be gone before the fire gets very big. Smoke alarms would be a good idea - especially if you are a heavy sleeper.

I agree with your concerns with open fiberglass.

 

[Jim26m]

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