Hot water heater on raw water cooled boat

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Ed H

Ed H

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Sep 15, 2010
244
Hunter 33_77-83 Regent Point Marina, Virginia
The hot water heater on my 1981 Hunter 33 does not work. With the raw water cooled engine, the hot water heater only ran when hooked to shore power. But it seems to me if I am at a dock, I would take my shower at the bath house. What am I missing? With an average 6 gal marine hot water heater, how long does the water remain hot once you leave the dock? I would like a hot shower after an 8 hour sail to a cove but if the water won't still be hot then I will pass on installing a new hot water heater. Thanks guys. Ed H
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Not what you want to hear but the water might be just luke warm in eight hours. How far away are you from installing a new engine? Or converting over to a heat exchanger? Then a new heater would make sense. Are you sure you can't repair your old one for use at the dock?
 
Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Mine keeps water hot for a good 12 hours and warm for 24
Is your hot water plumbing from the engine correct? should have a hose from before the thermostat to the heater and return hose from the heater to a Y in the raw water intake line.
 
Ed H

Ed H

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Sep 15, 2010
244
Hunter 33_77-83 Regent Point Marina, Virginia
Ed Schenck said:
How far away are you from installing a new engine? Or converting over to a heat exchanger? Then a new heater would make sense. Are you sure you can't repair your old one for use at the dock?
Click to expand
Oh great Ed, thanks for jinxing me. The engine was fine until I just read your reply.... I have not read anything good about the add-on heat exchangers. Plus it seems crowded enough down there. I believe it is the original water heater; very corroded. When I drained it (while winterizing the fresh water system) some black water came out. Not sure I want to put any money into it.
 
Ed H

Ed H

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Sep 15, 2010
244
Hunter 33_77-83 Regent Point Marina, Virginia
Bill Roosa said:
Mine keeps water hot for a good 12 hours and warm for 24
Is your hot water plumbing from the engine correct? should have a hose from before the thermostat to the heater and return hose from the heater to a Y in the raw water intake line.
Click to expand
Hey Bill- There are no hoses running from the engine to the hot water heater. Just a cold fresh water in line and the hot water out hose. It is my understanding you can't/shouldn't take your exhaust water to the hot water heater...While I can't swear to it, I do not remember seeing any in/out connections for a heat exchanger in the hot water heater. I will check on it Saturday... How many gallons is your hot water heater? I would be happy with hot water after 12 hours/warm up to 24... It would even be worth it to make an insulating cover for it like they sell for residential hot water heaters.
 
Manny

Manny

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Oct 5, 2006
983
Hunter 82? 37 Cutter Wherever the wind takes me
What model water heater do you have? Mine stays hot for at least 12 to 16 hours if not more, don't remember the manufacturer but I think it's a kuuma (or it's predecessor) - it's the squarish 6 gallon model. I barely use it at all, only when it starts getting colder outside. One thing you can do is make sure you don't actually use the hot water until you need it, otherwise your replenishing its tank with cold water.

M
 
B

Benny17441

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May 24, 2004
7,164
CC 30 South Florida
How long will the hot water last will depend largely on the ambient temperature as well as the insulation around the tank. Adjust the thermostat on the water heater to allow the water to pre-heat to a higher temperature. Do not open the hot water valve until you are ready to take a shower as flowing hot water will be replaced by cool water which will in turn cool the water in the tank faster. If the boat is already plumbed for hot and cold running water I would go ahead and replace the water heater even if it only heats water at the dock. Taking a lukewarm shower beats a freezing one any day and while at the dock you will enjoy having hot water for doing dishes or defrosting meats. If you decide against replacing the water heater then a sun-shower which can be carried on deck can be used for those days spent at the cove.
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
So Ed you are saying that the hot water heater is not plumbed to the engine? They did, maybe still do, make a heater that is 110v only. So if you buy a new one it should have two sets of in/out connectors, a pair for house water and a pair for engine water. I have this Seward: http://images.jamestowndistributors.com/woeimages/plumbing/large/s6001.jpg . Notice that it has both in/out pairs on the same side. I have a different model where the engine in/out is on the other side. That side faces the engine(picture). The side seen in the link faces aft. But stays warm for twelve hours? Maybe.
 

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Ed H

Ed H

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Sep 15, 2010
244
Hunter 33_77-83 Regent Point Marina, Virginia
Ed Schenck said:
So Ed you are saying that the hot water heater is not plumbed to the engine? .
Click to expand
Ed S- Correct, it is not plumbed to the engine... Yes, that is the type of new hot water heater I am looking at. The opening for installation is only 13" wide and that one will fit... Keeping in mind that one day I may need to have a new fresh water cooled Yanmar installed, would it be ok now to buy a new HWH with a heat exchanger but only operate it with shore power? There would be nothing at all hooked to or flowing in the "engine side".
Manny and Benny- Very good point: I will have to advise the crew not to use any hot water until after the shower(s)... I do not know what brand the old one is, but it is round. Pretty sure it is original because I am going to have to cut it into pieces to get it out. I guess it could have been installed during an engine rebuild, but the PO never mentioned a rebuild.
 
Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
You might as well plumb a new tank to the raw water. You will have to run hoses eventually if you upgrade so make them longer than needed to accomidat that. The salt water is not going to hurt the SS tubing in the heater and you will have hot water every time you run the engine for more than 20 minutes.
I don't see the down side except fiting the new heater into the limited space.
 
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kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
Ed, my buddy's ('78) 33 has an engine warmed hot water tank and it works. Takes longer than with a fresh water cooled engine but his old 2QM heats it up after 30 minutes or so.. It probably helps that our seawater does not get any cooler than around 65F in the winter.. once heated, it stays that way overnight. I'll try to get some pictures, maybe today to post..
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Yep, the original in mine was also round. Still an outline stain back there. It had already been replaced with square when I bought her in '98. You could, as Bill suggests, go ahead and plumb to engine. You will need some fittings though.
 
Redbeard33

Redbeard33

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Oct 25, 2011
115
Hunter 1980 H33-C Annapolis
the reason it was never hooked up or was eventually diconnected from the engine is that the 2qm15 is raw water cooled and the thermostat is set much lower, i believe it is set to start opening around 110 and fully opened at 120, this is because salt and other solids will precipitate out of the cooling water and scale up the coolant passages if operated at a higher temp. So best case scenario you start out with 120 degree water in the tank if you expect 100% efficiency. I have done a fair amount of research into converting to fresh water cooling for the 2qm15 mainly because the exhaust manifold in no longer in production and is a death sentence if it corrodes but added bonuses are better efficiency and all the hot water you want. also i have the shop manual on pdf for any H-33 owners with the original engine, i just got done with a rebuild and had it printed at kinkos and bound
 
John T1594

John T1594

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Jun 4, 2004
834
Hunter 340 Forked River, NJ
Solar Shower

You might also want to consider a cheap alternate solution in a H20 SunShower. These 2.5 - 5 gal solar showers are great after a long day out on the water and can be used as a back-up to what is left in your water heater. You fill them with fresh water and leave them out on the deck for a few hours, hoist it up on one of your halyards and Voila' you have a hot, gravity fed shower. Not as private as down below but great for washing off the salt and sand. West Marine, Defender and other stores carry the - Maybe HOW also.
 
G

Gudenuph

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Aug 4, 2009
204
Oday 25 Olympia
If it is only hygene, a teakettle of hot water and a thick wash cloth is all it takes to do a very satisfactory job.
Geohan
 
S

sandpiper10471

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May 31, 2007
763
Hunter 37 cutter Blind River
Or you could get one of those pressurized garden weed sprayers. Paint it black and lash it to the deck in the sun. When hot, put the hose through the head portlight and shower to your heart's content in privacy. Hot pressure water with no electricity or plumbing.
 
Ed H

Ed H

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Sep 15, 2010
244
Hunter 33_77-83 Regent Point Marina, Virginia
Hey friends- Thanks for coming through again with all the great input.
 
H33CRich

H33CRich

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Sep 26, 2011
228
Hunter 33_77-83 Cedar Creek Sailing Center, NJ
Ed H said:
The hot water heater on my 1981 Hunter 33 does not work. With the raw water cooled engine, the hot water heater only ran when hooked to shore power. But it seems to me if I am at a dock, I would take my shower at the bath house. What am I missing? With an average 6 gal marine hot water heater, how long does the water remain hot once you leave the dock? I would like a hot shower after an 8 hour sail to a cove but if the water won't still be hot then I will pass on installing a new hot water heater. Thanks guys. Ed H
Click to expand
My approach is to take the path Dale Baker took with the Excel LPG water heater. Mount it to the bulkhead in the starboard locker. It's detailed here: http://hunter.sailboatowners.com/in...7&cat_id=28&aid=7433&page=article&mn=33_77-83
 
L

Larry Laurentius

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Oct 30, 2011
50
Rosewood Hunter 54 New York NY
Just a note that I was seriously corrected by a 91 year old German boat surveyor years ago There is no such thing as a "Hot Water Heater" Its just a Water Heater.After one hour of hearing this, I never said Hot Water Heater again...
LTL
 
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