Source of hot water while cruising

[SVRocinante]

Good day all

We’ve been away from marinas for 5 months now (East coast, USA) and I have a question for those of you that do extended cruising and primarily anchor out. While in a marina, we plug in and have hot water and after any motoring we also have hot water. But once you’ve been sitting at anchor for a couple of days, what do you do?

We don’t need a lot, and we’ve simply been making due with not having it, since it hasn’t gotten that cold yet; but It would be nice to have just enough for our morning hygiene rituals & it sure as heck would help when doing the dishes.

If we need enough for both of us to shower, then I simply run the engine, but it seems like a waste to do so every morning for the 30 minutes or so it takes for the water to heat up, especially since I don’t need to run it to charge our batteries... then it would be a no-brainer.

What do you folks do?

As always, thanks in advance!

[Kenomac]

We run the generator to energize the heating element inside the hot water tank.

[atmartin]

Boil water on the stove. Mix with a pitcher of lukewarm to taste in a large mixing bowl squatting in the cockpit. Pour water over yourself with a small bowl or ladle. We did this up until about December on LI (nights dropping to the 30s) on our last boat. It won't work all winter.

I'm thinking now of trying the same thing inside our current boat with a daytank and a simple valve. Same heating method. You could always run a portable generator for your 120V water heater, right? Or solar shower? Until it gets real cold.

At least in cold weather, you don't have to shower as often.

[nautical62]

Sun shower, in the sun for a couple hours.

Sun shower with some hot water from the stove poured in.

Idle the engine, to top off the batteries and create hot water. Idling doesn't burn that much fuel.

Cruise where the water is warm and clean, such as the Bahamas. Jump in, get out, lather up, jump in again.

For car camping, I use a helios system and love it, but for cruising, there's always somewhere to hang a simple, cheap sun shower.

[Cheechako]

I always charged by running the engine, every day I had hot water that way. Even hot enough in the am after running the engine the night before.
If I were to outfit another boat I would probably go with a combination of a little bit of solar and running the engine. I dislike having too much stuff hanging above the boat like a massive solar panel and wind machine. I've never found running the engine a detriment on any of my boats.

[SVRocinante]

Thanks kenomac, atmartin & nautical62

Considered using my portable generator vs engine not sure which is more “efficient” that’s one of the reasons i was asking what others do.

Considered the solar shower, but didn’t think it would retain the heat from the previous day... does it?

Yep, could heat up water on the stovetop...

Cruising the Bahamas sounds like a good solution!

[SVRocinante]

Thanks Cheechaco

Good to know; guessing my aversion to running the engine is probably misguided.
I’ve mostly heard/read that running the engine at idle is “bad” for it... I might be taking that statement too far!

[Cheechako]

Originally Posted by SVRocinante

Thanks Cheechaco

Good to know; guessing my aversion to running the engine is probably misguided.
I’ve mostly heard/read that running the engine at idle is “bad” for it... I might be taking that statement too far!

It's been long debated for sure. Valid points on both sides. Truckers used to idle continuously and get 500k miles on their trucks, so I said "fair enough". Also was careful to not low idle forever. When charging at first, you could hear the engine lug a bit, so it's not like no load. When the charging backed off, I would lower the rpm a bit. I also made water with the engine on some boats.
I figure if I'm making amps, making water and making heated water , all hidden under deck.... that's not a bad thing!
The worst thing I've seen for diesel engines is lack of use.

[SVRocinante]

Originally Posted by Cheechako

It's been long debated for sure. Valid points on both sides. Truckers used to idle continuously and get 500k miles on their trucks, so I said "fair enough". Also was careful to not low idle forever. When charging at first, you could hear the engine lug a bit, so it's not like no load. When the charging backed off, I would lower the rpm a bit. I also made water with the engine on some boats.
I figure if I'm making amps, making water and making heated water , all hidden under deck.... that's not a bad thing!
The worst thing I've seen for diesel engines is lack of use.

Thanks!

[Sailor647]

Perhaps the issue is with the insulation around your water heater? Ours is 30 years old, original to the boat, and built like a tank.

The water in our water heater stays hot for about three days after an hour of motoring or running the engine to charge the batteries.

If we are at anchor for a week or more and don't want/need to run the engine (solar is keeping the batteries charged or we're conserving fuel for a passage) we use a solar shower left in the sun for an hour or so. Any more than that and it gets scalding hot.

[MartinR]

I have a Webasto Thermo top hooked up to my water heater. I run it for 40 minutes every 2 days to supply all the hot water needed. Uses very little fuel and is quiet.

[Privilege]

I have an instantaneous propane water heater. Search for one that doesn't need 110v for ignition. A single 'D' cell battery will last years. Two barbecue-size tanks last me four months - full time live aboard. The extra safety concerns are not an issue as i already have a propane stove plumbed in. The only downside is that it needs to vent overboard which I have achieved with a mushroom vent.

[SVRocinante]

Originally Posted by Sailor647

Perhaps the issue is with the insulation around your water heater? Ours is 30 years old, original to the boat, and built like a tank.

The water in our water heater stays hot for about three days after an hour of motoring or running the engine to charge the batteries.

Wow! Thanks! Something for me to look at - ours only stays hot for a day or so!

[SVRocinante]

Originally Posted by MartinR

I have a Webasto Thermo top hooked up to my water heater. I run it for 40 minutes every 2 days to supply all the hot water needed. Uses very little fuel and is quiet.

Thanks! We have a Webasto Air Top heater - love it! The Thermo top might be overkill for our needs, but something to file away if we start to spend more time up north.

[noelex 77]

We have a small tank that can filled with hot water from the:

Electric kettle
Propane stove
Diesel drip heater (Reflex)
Sola bag


The water is mixed to the ideal temperature and from there it is fed to a normal electric pump and shower rose.

The water is always a perfect temperature without fiddling with the hot and cold mix. The tank is in the shower so the hose run is short, minimising the time to pump out the cold water in the pipe. We pump the first few litres back into the tank until the water is perfect. I hate cold showers. This minimises water usage. We can pick the best method of heating the water depending on the conditions, and multiple sources provides redundancy.

It is a great system and would not be difficult to retrofit to most boats.