How cold can I sleep onboard?

[Mike OReilly]

Originally Posted by DanielI

We’d like to get out sailing for a few more days this season before hauling out, but lows in our area will be hitting the low 40s (highs around 70). Last time we slept over, it was still warm in the evening, and we went to bed with everything open, and woke up quite chilled.

I’m wondering, with no cabin heat, how low a temperature is reasonable to sleep onboard if we close everything up before we go to sleep?

Depends on you, your boat, and what kind of sleeping system you have. It's easy to find sleeping bags rated to well below freezing. But I find it really is quite variable from person to person.

It's pretty common for us to wake up to near-zero temperatures, which in that funny scale would be in the 30's. 40 would be fine for us.


Be careful about sealing up the boat fully. It does keep warmth in, but also keeps all your breath moisture in. Condensation becomes a real problem. We tend to keep a hatch partially open no matter what the temperature.

[SalingSue]

With the right sleeping equipment you can sleep in some majorly cold weather.

That being said, you’re going to have condensation on the inside of the boat, frozen tanks, etc. Not fun.

If I had to, I have the sleeping equipment to spend the night in a small RIB in the middle of winter, but if I’m not getting paid to do it, or have a REALLY large need, forget that!

Adding a propane heater on most boats isn’t that bad money wise, if you are sailing in cold areas you are really going to want a better solution, propane or diesel heater or something, this will make life much more civilized and also be much better for the boat by keeping tank and other systems warm as well as humidity down.

[sailorboy1]

Originally Posted by DanielI

We’d like to get out sailing for a few more days this season before hauling out, but lows in our area will be hitting the low 40s (highs around 70). Last time we slept over, it was still warm in the evening, and we went to bed with everything open, and woke up quite chilled.

I’m wondering, with no cabin heat, how low a temperature is reasonable to sleep onboard if we close everything up before we go to sleep?

I have done it in the low 30s lots of times. But if it isnt going to get back to the 60s in the day it is time to pack it in.

[fatherchronica]

Dr. David Lewis sleep as best he could circumnavigating Antarctica in a rotten sleeping bag and rotted off kangaroo hide weather gear">foul weather gear. He described his fingers as looking like sausages, but he spent his life pushing the boundaries of physical and mental comfort. And I suppose he was not actually ever cruising as Emmanuel Lewis would describe it in the dictionary.

[gonesail]

Originally Posted by fatherchronica

Dr. David Lewis sleep as best he could circumnavigating Antarctica in a rotten sleeping bag and rotted off kangaroo hide foul weather gear. He described his fingers as looking like sausages, but he spent his life pushing the boundaries of physical and mental comfort. And I suppose he was not actually ever cruising as Emmanuel Lewis would describe it in the dictionary.

that was a great book he wrote .. Ice Bird. read it a few times

[StoneCrab]

There is no such thing as too cold or bad weather, just bad clothing or bedding.

Modern textiles and insulation have made just about any temperature tolerable. Just follow all the usual advice regarding layering and venting.

I'll admit cold and humid are a tough combination. I think you are better leaving the hatches open to reduce humidity and dealing with the lower temperature by selecting the best bedding and layered clothing.

Don't sleep in your day clothing. Always go to bed clean and dry.

I'm a big fan of polypropylene fleece and down.

[Hardhead]

Originally Posted by TeddyDiver

... Got so aclimatized to cold I could not stay in normal room temperature more than 20min.

I've had the same experience - spent 2 years living in a mid-atlantic beach house, with practically no heat. After a month or two - you feel great and the air is crisp and breathable. I'd then go to visit relatives, and their houses would seem stifling at 70 degrees - I actually didn't like it. It was amazing how I became acclimatized to living in a much colder house then I'd ever been before.

[Dockhead]

Originally Posted by TrentePieds

. . . Your environmental enemy is NOT the cold. It's lack of ventilation. Lack of ventilation causes condensation, whereas keeping the temperature WITHIN the boat the same as the ambient temperature WITHOUT, prevents condensation. Once you (or the boat) get(s) wet from condensation caused by your breathing of by any other kind of source, you'll have lost the battle, and hypothermia is a real possibility.

Furthermore, once things are wet, you have zero possibility of drying them out without artificial heat and things spiral downwards from there. Cooking should be done with open hatches and the boat should be thoroughly ventilated once the use of the stove has ceased. . .

This is all correct. You do really need some heat to be comfortable, i.e. dry. Wet and cold with condensation dripping from the hatches is absolutely misery.


The OP should consider installing either an Espar type heater, or a bulkhead heater. Or simplest of all -- electric if he's on shore power.


You don't need to make the boat that warm, certainly not while you're sleeping, but just a little heat -- plus be sure ventilation is working -- will keep things try, and that is absolutely crucial for the reasons TrentePieds says.



I would not sleep on a boat at temps below 10C, without heat (and good ventilation). It's miserable.

[Mike OReilly]

For decades now we have cruised with little more than an alcohol heater. One of these days I might install a bulkhead diesel furnace, or perhaps a woodstove, but so far we've not needed it. We might run the heater a dozen times in six months of warm-weather cruising.

I mostly cruise in the upper latitudes, generally around 48º-50º N. Places like Lake Superior and now Newfoundland. Morning temperatures are routinely in the low single digits (speaking Celsius of course). So far, the alcohol heater is all I've ever needed. But if I was going into the real north (as DH does), or planning to winter on board, then I'd need more.

But as I said, it really depends on the individual. I'm acclimatized to a cooler temperature. I think 20ºC is hot! So it's hard to offer a general answer to the OP's question.

[Cheechako]

Cruising in the PNW we often were 45 degree days or lower nights. Good comforter for sleep and you'll be fine.
Take a clay pot for the stove top to use as a heater to take the chill off if you want. Doesn't work great but works a bit.
or just buy yourself a kerosene heater to use, not expensive and work very well. Leave a hatch cracked open though.

[rmlarson1098]

Originally Posted by DanielI

We’d like to get out sailing for a few more days this season before hauling out, but lows in our area will be hitting the low 40s (highs around 70). Last time we slept over, it was still warm in the evening, and we went to bed with everything open, and woke up quite chilled.

I’m wondering, with no cabin heat, how low a temperature is reasonable to sleep onboard if we close everything up before we go to sleep?

As has been mentioned, buy the sleeping bag you expect to need - depending on local cold-weather conditions - and if it gets really cold wear a stocking cap when sleeping.
This is one case where people can take more than most boats. Mountaineers sleep in thin little tents with temps to -30 F. and howling winds. Compared to that your vessel is a snug abode - with a proper sleeping bag - in any but arctic conditions.
Keep in mind that while goose down rules in dry, cold weather, it sucks when it gets wet. Synthetic bags probably best on the water, as they offer some warmth when wet. Or so 'they' say.

[waterman46]

Originally Posted by DanielI

We’d like to get out sailing for a few more days this season before hauling out, but lows in our area will be hitting the low 40s (highs around 70). Last time we slept over, it was still warm in the evening, and we went to bed with everything open, and woke up quite chilled.

I’m wondering, with no cabin heat, how low a temperature is reasonable to sleep onboard if we close everything up before we go to sleep?

Sorry but I think this is not possible to answer by anyone other than yourself, from experience as everyone has different comfort zones.

Seriously, just see the REI information on sleeping bags and you'll get guidance on what equipment works for different temperature ranges.
One thing that alway bothers me in cold nights is my face getting cold. Still have to breathe right? Mummy bags you can pull the top down over your head and only your nose sticking out. If using regular blankets I put a small blanket or towel over the upper part of face.

[Shrew]

I've spent many, many nights mountaineering in below freezing temps. I've spent countless nights backpacking in the winter. I have a -20F down down mummy bag. Once it gets cold enough (-10 ~ -15), there is no 'sleep'. It's, a best, restless napping while prayer for the dawn to bring the temps back up.

In those situations, it's very hard to get out of your bag.

[joelhemington]

Originally Posted by JPA Cate

tkeithlu's experience is similar to ours. Jim and I have spent our first winter down under, outside of the tropics. We found temps of -1 d. C on land, one morning cold enough to have ice on deck. We found ourselves sleeping in thermal underwear, and a sleeping bag would have been good. We were sleeping under a summer comforter, with blankets on top of it. I wore wool and polypropylene socks. When you get up the icy air has to warm before it touches your tender, astonished flesh. You may wear thermal underwear for months!

The other issue to address, is the boat will get condensation in it, and it gets like a rain forest below. One needs to insulate all the under deck area, down to the water line. We had various kinds of damage because we weren't really tuned into the problem beforehand. If we spend another winter down here, we certainly will have to make a more serious effort.

And, we do have a heater. We were using ~ 20 liters a week for charging batteries (short days, low sun angle, not much help from solar panels, lots of cloud) and heating the saloon. (The latitude is 43 deg. south, so not really extreme. It is tropical acclimatization that is our underlying problem.)

Ann

An item that was becoming quite popular back in my backpacking days, was a bivy sack. These function as a one man tent and will keep you dry as well as keeping the skeeters out. Could be a good item for cockpit sleeping as well while under sail with a two person crew. https://www.rei.com/product/147955/r...Gg9SisQHBcl5Us And don't overlook the silk bag liners, an excellent way to add 10 degrees on a cold night and great for summer use. https://www.amazon.com/Browint-Sleep...&hvdev=c&hvdvc

[joelhemington]

Originally Posted by Mike OReilly

For decades now we have cruised with little more than an alcohol heater. One of these days I might install a bulkhead diesel furnace, or perhaps a woodstove, but so far we've not needed it. We might run the heater a dozen times in six months of warm-weather cruising.

I mostly cruise in the upper latitudes, generally around 48º-50º N. Places like Lake Superior and now Newfoundland. Morning temperatures are routinely in the low single digits (speaking Celsius of course). So far, the alcohol heater is all I've ever needed. But if I was going into the real north (as DH does), or planning to winter on board, then I'd need more.

But as I said, it really depends on the individual. I'm acclimatized to a cooler temperature. I think 20ºC is hot! So it's hard to offer a general answer to the OP's question.

Yep, it all depends on what you're used to. I lived in the Rockies (pretty high up) for two winters and a 20 degree F day was a tee shirt day for us - of course I was much younger and slightly more foolish then