Reply
 
Thread Tools Display Modes
 
Old 02-28-2014, 03:27 PM   #21
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Country: Bumpkin?
Join Date: Oct 2007
Posts: 9,996
Greetings,
Mr. Wilson. That crack head may be your sacrificial anode in the water tank. Any oxidation of the anode (either magnesium or aluminum) will produce those white chunks. Good time to check it while the tank is out. Might just need a good wipe down with an abrasive pad (scotchbrite) if it's not too wasted. The anode, NOT the crack head.
__________________
Advertisement

__________________
RTF
RT Firefly is offline   Reply With Quote
Old 02-28-2014, 04:03 PM   #22
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
I had the plastic inlet tube of my home's water heater fail and send little pieces of white plastic all through the water system. I had to clean all the screens and flush all the pipes. This is a possibility here as well.
__________________

rwidman is offline   Reply With Quote
Old 02-28-2014, 04:07 PM   #23
TF Site Team
 
FlyWright's Avatar
 
City: California Delta and SF Bay
Country: Sacramento, CA, USA (boat in Vallejo)
Vessel Name: FlyWright
Vessel Model: Marshall Californian 34 LRC
Join Date: Apr 2008
Posts: 10,179
Quote:
Originally Posted by Wilson View Post
Well this all good information thanks guys. The water heater that I just pulled to check out its condition was a 3 gallon capable of being plumbed to the engine coolant. The PO had hoses on the tank, but it looks like it was never plumbed to the engine. I'm gonna guess that he could not figure out where to tie it in at. I would also have to look around a bit to figure it out. The tank looks nice inside its rusted box! Of course I can't vouch for the internals of the tank, when I drained it lots of white chunks came out, looked like a crack head was living in my ER... I think I'll try and reuse this tank for now, if I can figure out how to plumb it to the engine.
Why reuse an undersized rusty WH with white flakes coming out of it? A new marine WH is not that expensive. It'll come with directions for installation or hire a pro to install it.

Three gallons sure isn't much. I think I spent $300 when I replaced my 11 gal WH with a Force/Kuuma. That was in August 2008.
__________________
Al

Custom Google Trawler Forum Search
FlyWright is online now   Reply With Quote
Old 02-28-2014, 06:44 PM   #24
Senior Member
 
City: Green Cove Springs, Florida
Country: USA
Join Date: Feb 2012
Posts: 210
Send a message via Skype™ to bglad
I have seen quite a few problems related to engines plumbed to water heaters some caused by what I would consider inappropriate applications such as aluminum nipples plumbed to raw water cooled engines. I know of a 3208 that was toasted due to a blown off hose. I suggest valves at the engine so it can be shut off when not needed. You know it won't be a problem until you are pushing hard and at that moment the least of your concerns would be whether there was hot water in the tank or not.

Most of the hands-on guys who lurk around here probably have nothing to worry about. They are paying enough attention to not get caught with bad hoses and clamps on their water heater plumbing.
bglad is offline   Reply With Quote
Old 02-28-2014, 07:00 PM   #25
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,567
One name the "rag & stick" fraternity here use for powerboats is "hot water boats". Let`s not disturb that. Doriana heats water using coolant from both engines(OP`s Admiral addicted to hot showers?) and the HWS is also served by the genset. Here`s to hot showers, however brief.
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 02-28-2014, 09:30 PM   #26
Senior Member
 
MC Escher's Avatar
 
City: Central Ohio
Country: USA
Join Date: Sep 2013
Posts: 151
Quote:
Originally Posted by WesK View Post
I'm not buying that for a minute.

Sorry but, that's not my opinion... that's physics. As you yourself observed later in your response, all of the electricity used goes into making heat.



Short of actually burning dollar bills, running electricity through a resistor to make heat is the most expensive way to make heat.

Apples and Oranges. I said electricity is more efficient, which it is. Cost comparisons are a completely different and rather complex analysis.



Electric resistance heat is the last resort. People heat their homes with gas, oil or heat pumps because they are all less costly ways of doing it.
Nobody uses an electric water heater if gas is an option.


That depends on the price of fuel available fuels and the cost of a Kilowatt; both of which have a great deal of regional variance.
Someone living in Arizona and drawing power from Hoover Dam might well come to a different conclusion than someone living in the OH/PA/WV region.

More importantly, I believe we are talking about a BOAT, not a house. I'll come back to that.




You may make the argument that 100% of the electricity used to heat water (or a building) goes into making heat...

Not MAY make. DID make. And it's not an argument, it is a simple statement of fact, no more remarkable that observing that the Earth's gravity at sea level is approximately 9.8 Meters/Second/Second.



...but how was that electricity produced? In most parts of the country it is produced by burning fuel to make heat to make steam to turn a generator to produce electricity. Then, it is delivered over hundreds of miles of wire with some loss to be converted back to heat.

As I said, we're not talking about use in a building on dry land, we're talking about use in a boat. There is therefore, no production of steam, no "Grid Production" generator to turn, and no "Hundreds of Miles" of wire loss to contend with. Nor, for that matter are there transformers, switch yards and all the other accoutrement of a land based power grid.

I was very clear that my understanding of the marine application of this technology was limited and I wished mainly to point out that regardless of whether you use combustion or electricity that it would take quite a bit of energy to heat water quickly enough to give a flow rate of several gallons per minute.




Now think of the your last sentence - You advocate burning diesel or gasoline to produce heat to rotate a generator to produce electricity to run through a resistor to produce heat to heat water. Think about that for a minute.

I did think about it. Respectfully, you should follow your own advice.

In the first place, I didn't "advocate" anything. I merely made a few simple and (I thought), non-controversial observations.

In the SECOND place, if YOU would "think about that for a minute" it might occur to you that unless you are on a sailboat without any backup motive power or electrical generation capacity at all, that you are ALREADY carrying gasoline or diesel and you ALREADY have a generator on board.




Simplest and most efficient - put the flame under the water and be done with it. Only when that cannot be done should another solution be considered.

You know, I am practically a complete land-lubber whose only boating experience has been on a lake; but it seems to me that adding an electrical tankless water heater to a boat that ALREADY has electrical generation capabilities and is ALREADY carrying liquid fuel for that purpose is a lot simpler than adding ANOTHER tank to carry a gaseous fuel to fuel a propane powered "on demand" heater.

Not to mention that a tankless water heater isn't a BBQ. It needs quite a bit more flow capacity to do it's job, which a 20lb BBQ won't provide. At a minimum you'll need a 100 pound tank, and even there... as it gets lower the pressure and flow volume drop. Which will happen faster than you think, because a hundred pound tank holds less than 20 gallons of propane.

So NOW we're talking about adding propane tanks to hold the fuel. Probably three or four 100 pound tanks on a manifold system. Which of course will need to be refueled on a regular basis.

Now as I said, MY only experience with boats in on a Lake. So I don't know... Is a propane pumping station a common thing at the marina's you frequent?


Now that THAT is done with, I am curious as to what I did to earn the dressing down you gave me.

If I have inadvertently done something since arriving here that has offended you, I offer my sincerest apologies and ask only what I can do to make it up to you.

If you were in a bad mood when you responded to my post, I forgive you. It happens.

If you had no intention of coming off as hostile as you did and this is simply a function of the medium; no worries... The written medium can be misleading as to mood and intent.

If all of this is simply my imagination and I was reading a hostility into your post that was never there, then once again, I apologize. As I said, the medium can be misleading.
__________________
If God didn't want me to walk on the grass, he wouldn't have left it on the ground.
MC Escher is offline   Reply With Quote
Old 02-28-2014, 11:13 PM   #27
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,886
Electric water heat from a gennie is not efficient. A good diesel is about 40% efficient at converting fuel energy into electrical energy. A little boat gennie is probably around 25%. So only 25% of the energy in the diesel makes it into heat in the tank.

But the gennie/elec water heater is simple. And its use is limited. Take a cruising boat and look at the fuel consumed pushing it through the water (lots of gallons) and the amount running the gennie to heat water, however inefficient (few gallons). There are places to save fuel, but heating water with the gennie is not one of them. Keep it simple.

If you can capture heat from a main engine, better yet. But spending a few hundred extra for that heater pays for a lot of gennie fuel. That was my calculus, resulting in a simple electric water heater.
Ski in NC is online now   Reply With Quote
Old 02-28-2014, 11:57 PM   #28
Guru
 
brian eiland's Avatar
 
City: St Augustine, FL
Country: USA & Thailand
Vessel Name: RunningTide
Vessel Model: 37 Louisiane catamaran
Join Date: Jul 2013
Posts: 890
Quote:
Originally Posted by Richard W View Post
I don't see why small electric tankless heater would not work for sporadic needs if boat can generate 25A 120V AC or 3kW over required time of use. Here is the smallest, simplest, and cheapest example I could find in 1 google search: Stiebel Eltron 220816 Mini 3 Point-of-Use Tankless Electric Water Heater - 3.0 kW, 0.40 GPM
But one bummer, "It is designed to be fed with cold water only rather than with hot water flowing into it"

Just wanted to make a note of this,...and follow the discussion.
brian eiland is offline   Reply With Quote
Old 03-01-2014, 12:34 AM   #29
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,567
Quote:
Originally Posted by Ski in NC View Post
Electric water heat from a gennie is not efficient. A good diesel is about 40% efficient at converting fuel energy into electrical energy. A little boat gennie is probably around 25%. So only 25% of the energy in the diesel makes it into heat in the tank...
If you already run the genset to recharge batteries, or the eutectic fridge/freezer, or to cook, as many do, it can heat water at no or little extra fuel use or genset hours.
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 03-01-2014, 02:49 AM   #30
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,886
That was rather my point, made in further paragraphs... It costs very little to heat water with the gennie even though it is not very efficient.
Ski in NC is online now   Reply With Quote
Old 03-01-2014, 07:21 AM   #31
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,525
The co generation concept , the engine or noisemaker is on for its purpose , so capturing waste heat is a no brainier for efficiency.

The danger to the engine is very minor , I have never seen or heard of it happening in 55 years , so far.

The DANGER of a leak of the engine coolant into the fresh water , which could poison the FW does in theory exist.

The solution is a double wall heating element , common in house alt energy setups , probably too expensive for most boaters.

Simple , if you TASTE anti-freez , dont drink the water.
FF is offline   Reply With Quote
Old 03-01-2014, 07:29 AM   #32
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,313
Quote:
Originally Posted by WesK View Post
That water heater needs a lot of electrical power. You would need a bilge full of batteries and a humongous inverter to power it and the engine's alternator would take many hours to recharge the batteries. It's simply not practical on most boats unless you have a genset.

There is nothing wrong with heating water using engine coolant and it's "free".

Look around at other boats, especially production boats. These people have figured out what works and what doesn't. They have already considered what you are proposing and figured out that it's not the best solution.


to reiterate, in your case it's all about the Inverter, as no many how batteries you have, the Inverter will have to transform that power.

Also, having lived in Germany with an on demand water heater for 4 years, it would be about my last solution, but never on a boat in any case.

My Marine water heater will keep the water hot for more than a day, even turned off.

Good question though.
__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Old 03-01-2014, 10:41 AM   #33
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
MC Escher, I don't know why you took my post as being hostile. You posted your opinion, I posted mine. I don't think it is "physics", it's opinion. I stand by mine.
rwidman is offline   Reply With Quote
Old 03-02-2014, 08:18 AM   #34
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,525
My Marine water heater will keep the water hot for more than a day, even turned off.

The Rheem claims to loose 5 deg per 24 hours , starting with the usual 180F coolant heated water it should be good until its slowly filled with cold water from use.
FF is offline   Reply With Quote
Old 03-02-2014, 08:32 AM   #35
Veteran Member
 
City: Echo Bay
Country: Ontario, Canada
Vessel Name: The Lady "K"
Vessel Model: Custom Steel Trawler 48'
Join Date: Feb 2012
Posts: 32
The Takagi TK3 on-demand water heater is quite efficient . It is rated at 3 amps. Therefore you would Not need a " bilge full of batteries" to operate it, as WesK thinks in post #11.

My old Irish grandfather always told me it's best to know what one is talking about before going off half cocked.

BobH, in post #14, Sorry about your luck with your propane water heater.

Did you install it yourself? or did you have a Professional install it?
Capt Nemo is offline   Reply With Quote
Old 03-02-2014, 08:33 AM   #36
Guru
 
swampu's Avatar


 
City: Biloxi, MS
Country: USA
Vessel Name: Cajun Rose
Vessel Model: Biloxi Lugger
Join Date: Jul 2011
Posts: 1,144
Quote:
Originally Posted by Wxx3 View Post


to reiterate, in your case it's all about the Inverter, as no many how batteries you have, the Inverter will have to transform that power.

Also, having lived in Germany with an on demand water heater for 4 years, it would be about my last solution, but never on a boat in any case.

My Marine water heater will keep the water hot for more than a day, even turned off.

Good question though.
Mr. Wxx, could you elaborate on why? I've never used the on demand except for a very small and cheep unit that was electric and mounted under the sink. I wasn't very impressed with the output but I assumed a gas whole house unit would have the kinks worked out. I can assume things all day but I sure don't want to install something that is going to have to be pulled out after a couple of uses...
swampu is offline   Reply With Quote
Old 03-02-2014, 08:39 AM   #37
Scraping Paint
 
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
Quote:
Originally Posted by FF View Post

The DANGER of a leak of the engine coolant into the fresh water , which could poison the FW does in theory exist.
Pretty slim chance considering the potable water pressure is generally around 2 to 3 times the maximum engine coolant pressure.
RickB is offline   Reply With Quote
Old 03-02-2014, 09:47 AM   #38
Guru
 
Off Duty's Avatar
 
City: Tampa
Country: USA
Join Date: Oct 2013
Posts: 843
Just an aside, but maybe a cheap fix for your overheating concerns.
Why not install an alarm? When the engine heat reaches a certain point, the alarm sounds. You shut her down to find the problem?
Free hot water and peace of mind all at the same time

I'm one of those anti-propane types.
My home grill is charcoal, my house runs off of electricity.

Personally, I don't want much more than the little bottle one uses for the rod holder mounted grill, on board my boat. Just my personal paranoia

OD
Off Duty is offline   Reply With Quote
Old 03-02-2014, 09:59 AM   #39
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
Quote:
Originally Posted by Capt Nemo View Post
The Takagi TK3 on-demand water heater is quite efficient . It is rated at 3 amps. Therefore you would Not need a " bilge full of batteries" to operate it, as WesK thinks in post #11.

My old Irish grandfather always told me it's best to know what one is talking about before going off half cocked.
Seriously, 3 amps? Post a link.

And take a nice pill first.
rwidman is offline   Reply With Quote
Old 03-02-2014, 10:25 AM   #40
Guru
 
Off Duty's Avatar
 
City: Tampa
Country: USA
Join Date: Oct 2013
Posts: 843
Quote:
Originally Posted by WesK View Post
Seriously, 3 amps? Post a link.

And take a nice pill first.
Ask and ye shall receive:

http://www.takagi.com/download/product_manuals/T-K3.pdf
__________________

Off Duty is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 10:18 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012