Water Heater Placement on a 36 Footer

[Rustic Charm]

After a recent death on a boat from carbon monoxide fumes, Ive decided to dispense with my installing an LPG HW system and go back to installing a holding take type which operates off 110v or 220v ( havnt de ided which to go with yet).

The tank will also be plumbed to my engine fresh water system.

Where is the best place to put the tank, near the head/shower or near the engine?

My head/shower room is in the foxall. Engine way at the stern. It's. 36 footer with the helm at the stern.

[Sailmonkey]

Near the engine works best, if the round trip is too great the engine coolant won't circulate enough or at all to make hot water. Of course the inverse side of that is all the wasted water to get to hot water I the shower.


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[Reefmagnet]

Ours is up under the vee berth about as far forward as it can go. The long coolant hoses don't seem to have much effect at all (as in the water heats quickly). Of course with our little cc the distance is probably only around 6 m from engine to bow although galley sink, head sink and shower are all right beside the engine, so go figure!

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[Sailmonkey]

Originally Posted by Reefmagnet

Ours is up under the vee berth about as far forward as it can go. The long coolant hoses don't seem to have much effect at all (as in the water heats quickly). Of course with our little cc the distance is probably only around 6 m from engine to bow although galley sink, head sink and shower are all right beside the engine, so go figure!

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Last time I tried a long run the coolant essentially stopped flowing after the thermostat opened, unless the engine was really opened up.


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[Xthewater]

My vote close to the engine for following reasons.
Long run means the engine water pump has a harder time circulating coolant.
Long run means much more coolant.
Long hoses means more areas to possibly chaff through and coolant leak.

[wrwakefield]

Originally Posted by Rustic Charm

After a recent death on a boat from carbon monoxide fumes, Ive decided to dispense with my installing an LPG HW system and go back to installing a holding take type which operates off 110v or 220v ( havnt de ided which to go with yet).

The tank will also be plumbed to my engine fresh water system.

Where is the best place to put the tank, near the head/shower or near the engine?

My head/shower room is in the foxall. Engine way at the stern. It's. 36 footer with the helm at the stern.

Hi Rustic,

I did the same thing years ago on another boat. The Wallas propane water heater would set off the CO alarm after running 30 seconds or so- with the hatches and companionway wide open... No thank you... [The heater was mounted to the back of the gimbaled galley stove/oven, and the CO monitor was 12 feet away across the saloon...]

Unless you want to insulate the heater hose run from the engine- or heat the lockers it passes through on the round-trip to the water heater- I have found it ideal to locate closer to the engine. If the longer run is better, you may need a little DC hot water recirculation pump to keep the coolant flow to/from the engine moving. [I had to do this on a 47 footer I once had even though the water heater was only 15 feet (but 4 feet higher...) from the Yanmar engine...]

We went through the selection process and installation of a new water heater on our current boat just last year.

The results- along with some installation tips- are contained in this blog post which also links back to some similar discussions from this forum [in case you haven't seen it and are interested... or bored...]

Best wishes with your project!

Cheers!

Bill

[seasick]

On a 36' boat I would place it directly behind the gear box and high enough to avoid obstructing access to the stuffing box. This keeps the weight centered and the engine coolant lines short. Insulate the HW plumbing to distant sink and showers etc.

[Island Time O25]

Originally Posted by seasick

On a 36' boat I would place it directly behind the gear box and high enough to avoid obstructing access to the stuffing box. This keeps the weight centered and the engine coolant lines short. Insulate the HW plumbing to distant sink and showers etc.

On my 36 footer this is exactly where it is. I haven't used mine for the first few seasons after getting that boat as I don't really need hot water in the Summer but when I did attempt to use it turned out that PO, who moved the boat from Great Lakes to Florida, did not re-plumb the lines and he was still getting salt water in the heater from through hull. Of course the thing was like Swiss cheese when I attempted to use it for the first time.

I bought same size/model replacement and when I took the old one out through the lazarette hatch there was less than 1/4 inch on each side to spare but it did go through without a hitch. It sits on a fiberglass pan which drains into the bilge so if I have to bleed the heater it does not go near the batteries which are below it, under the pan. The whole set up works well as far as weight balance,etc.

[captain mitch]

Yup, I go with the closer to the engine.
One point though, stay away from West Marine water heaters, go with a brand name in heaters. We replaced a Seaward unit with a West (we were leaving for the islands and in a rush) now we await the Seaward replacement to arrive.
the West unit heats slow on electric power and is so poorly insulated that it barely holds a showers worth overnite. It looks just like a Seaward, but sure is a terrible performer.

[Stu Jackson]

Originally Posted by captain mitch

Yup, I go with the closer to the engine.
One point though, stay away from West Marine water heaters, go with a brand name in heaters. We replaced a Seaward unit with a West (we were leaving for the islands and in a rush) now we await the Seaward replacement to arrive.
the West unit heats slow on electric power and is so poorly insulated that it barely holds a showers worth overnite. It looks just like a Seaward, but sure is a terrible performer.

That could well be a Kuuma, a copy of the Seawards, but of this poor quality mentioned.

Our experience is that Seawards last 12-16 years on our C34s, which have the 6 gallon models. I just replaced one in 2013 that had been installed in around 1996-7, shortly before I bought the boat in 1998. We're a 1986 boat. Have fun with the math!

Quality order: Kuuma, Seaward, Raritan, IsoTemp (therm). The last is the only one supplied with a Thermostatic mixing valve at the outlet of the heater for the domestic side. There may well be a few others.

To the OP: yes, closest to the engine, but insulate the hot to the faucets and save some water unless you can recycle it or have a watermaker.

Good luck. Once the new ones are in and working, it's cockpit time!!!

[GILow]

RC, I applaud not using a LPG heater. They scare me silly.

However, given the climate in which you live might I suggest a diesel heater instead? No modifications to the engine cooling system and all that entails. No risk of compromising the engine cooling system. And most engine driven water heaters I have met only work after a fair bit of motoring. More than ideal for a sailing boat, and none I have used were particularly good even then.

You can pick up used webasto thermotops on the UK eBay for a song when they have been pulled from the wrecks of various European vans and trucks.

This is the path I will be taking when I finally get back to working on the boat later this year.

Matt


Sent from my iPhone so apologies for weird autocorrect typos.

[Rustic Charm]

Thanks everyone, I'm reading your responses now. I've been a bit buzy with work today. Fancy damn work interfering with my CF time :

Lot's of good suggestions. Ill get to them shortly.

[Rustic Charm]

Originally Posted by Sailmonkey

Near the engine works best, if the round trip is too great the engine coolant won't circulate enough or at all to make hot water. Of course the inverse side of that is all the wasted water to get to hot water I the shower.


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Someone suggested to me to resolve the lost water problem, to set up a return valve to the water tank so that when i run the tap, it all runs back to the water tank until it's hot enough for a shower then switch back to the shower.

[Rustic Charm]

Originally Posted by Xthewater

My vote close to the engine for following reasons.
Long run means the engine water pump has a harder time circulating coolant.
Long run means much more coolant.
Long hoses means more areas to possibly chaff through and coolant leak.

Good points

[Rustic Charm]

Originally Posted by wrwakefield

Hi Rustic,

I did the same thing years ago on another boat. The Wallas propane water heater would set off the CO alarm after running 30 seconds or so- with the hatches and companionway wide open... No thank you... [The heater was mounted to the back of the gimbaled galley stove/oven, and the CO monitor was 12 feet away across the saloon...]

Unless you want to insulate the heater hose run from the engine- or heat the lockers it passes through on the round-trip to the water heater- I have found it ideal to locate closer to the engine. If the longer run is better, you may need a little DC hot water recirculation pump to keep the coolant flow to/from the engine moving. [I had to do this on a 47 footer I once had even though the water heater was only 15 feet (but 4 feet higher...) from the Yanmar engine...]

We went through the selection process and installation of a new water heater on our current boat just last year.

The results- along with some installation tips- are contained in this blog post which also links back to some similar discussions from this forum [in case you haven't seen it and are interested... or bored...]

Best wishes with your project!

Cheers!

Bill

Brilliant. That's the model i was looking at. The manafacturuer has given me the supplier in Australia.

I want it to run on 'power' as well when 'out'. So i'd have to link it to a battery thingy is a 110 or 240 better for this purpose?