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Tankage

Jan 17, 2013
348
Catalina 310 St. Simons Island, GA
Due to a leak in my diesel tank on our last cruise, I am in the process of replacing the fuel tank and HW heater. Might as well replace the HW heater since it has to be pulled out anyway. The guy that I am hiring to do this is recommending a 6.4 gallon heater instead of the 20 gallon monstrosity that is in there now. Specifically the Isotherm basic model with the picture below. I have no concern about going that much smaller because with 2 of us onboard we will never run out of hot water. Although this does reduce our total water capacity from 55 gallons down to ~ 41. However, the 55 gallon number was never real because my boat is not plumbed to be able to separate the main water tank from the HWH so in actuality we have 35 gallons of usable water. Only works well for cruising because I carry another 20 gallons in jugs in the aft compartments. Anyone have any experience with these HWH's? The size difference compared to the current 20 gallon unit is huge and this will give me a lot more storage area (for water jugs?).

As for the fuel tank, the existing one is 20 gallons (19.5 to be exact) and I hoped to be able to increase the size but unfortunately there is no way to do that with the lack of clearance on top. Stretching the tank wider will not allow it to be secured to the tabs that are in place. So I am stuck with 20 gallons which is OK except that I am also planning to repower with a larger engine and so was hoping to increase fuel tank size. Jugs will have to be the answer there too.
bob
isotemp.jpg
 
Nov 18, 2010
2,370
Catalina 310 Hingham, MA
We replaced our water heater with the 6 gallon Kuma. One significant difference we noticed is how quick the water returns to ambient temp. This could be insulation but also that the volume of heated water is less. Typically we would have warm water for two days after running the engine. Now it's more like 12 hours.

With the extra space we installed a 6 gallon rum tank. Thought about a fuel day tank setup. But we can always sail.

On the fuel tank, did you install clean outs, a sump or extra pickups?
 
Jan 17, 2013
348
Catalina 310 St. Simons Island, GA
We replaced our water heater with the 6 gallon Kuma. One significant difference we noticed is how quick the water returns to ambient temp. This could be insulation but also that the volume of heated water is less. Typically we would have warm water for two days after running the engine. Now it's more like 12 hours.

With the extra space we installed a 6 gallon rum tank. Thought about a fuel day tank setup. But we can always sail.

On the fuel tank, did you install clean outs, a sump or extra pickups?
Jesse,
Haven't done anything on the fuel tank yet. What do you mean by sump, extra pickups etc? Also, can you describe a fuel day tank set-up? Thanks.
bob
 

JRT

.
Feb 14, 2017
1,783
Catalina 310 211 Lake Guntersville, AL
Curious what motor are you thinking of? As I recall you have a smaller one unique to hull #1

Also why did you all consider 6 gal vs 11 gal, the price seems like around a $100 more for the extra 4 gallons.
 
Last edited:
Jan 17, 2013
348
Catalina 310 St. Simons Island, GA
Curious what motor are you thinking of? As I recall you have a smaller one unique to hull #1

Also why did you all consider 6 gal vs 11 gal, the price seems like around a $100 more for the extra 4 gallons.
Main reason for the smaller HWH is that I do not anticipate needing more than 6 gallons of hot water and the smaller tank will open up so much more storage area down below. The current tank blocks everything including the sun. You ae correct in that I have a Yanmar 2GM20F which is an 18 hp engine. Works great and never have any issues but against wind or current I am making 3-4 knots tops at 3,200 - 3,300 rpm. I am looking at a Beta 30 as a replacement.
 
Nov 18, 2010
2,370
Catalina 310 Hingham, MA
Jesse,
Haven't done anything on the fuel tank yet. What do you mean by sump, extra pickups etc? Also, can you describe a fuel day tank set-up? Thanks.
bob
A sump is an international low point. Fuel contamination and water generally sinks to the bottom. Sump work a pickup at the low point will allow you to get the worst offenders out of the tank without opening it up for cleaning.

This is also where the multiple pick ups come in. By having a pick up in the sump dedicated to a fuel polishing loop then you can pull that crap from the bottom, polish it out and return it back into the tank.

Then the dedicated engine pick up can be an inch or two higher and that will prevent you from getting any water or contamination into the engine fuel filters.

For returns the engine and the polisher could share a return but having sperate would be better.

Mainesail has a post from 2010 that talks about this with pics. I should have one next week.

For the day tank, that could be a 6 gallon tank where I put my rum tank. An electric lift pump with a filter would move fuel from the main tank into the day tank. So the fuel in the day tank would be polished and get filtered again by your engine filters. Just another way to try and prevent build up that clogs filters and can cause problems. Plus it gives you some more range.

Good luck,

Jesse
 

RoyS

.
Jun 3, 2012
693
Hunter 33 Steamboat Wharf, Hull, MA
Be sure to put a mixing valve on your water heater. Two people can shower out of a six gallon water heater with a mixing valve 12 hours after motoring. Another nice feature is to purchase a stainless deep probe thermometer from a brewers supply and install it on a T fitting on your tank. You can tell at a glance if the water is hot enough for showering.
 
Jan 17, 2013
348
Catalina 310 St. Simons Island, GA
Be sure to put a mixing valve on your water heater. Two people can shower out of a six gallon water heater with a mixing valve 12 hours after motoring. Another nice feature is to purchase a stainless deep probe thermometer from a brewers supply and install it on a T fitting on your tank. You can tell at a glance if the water is hot enough for showering.
Roy,
Good advice thanks. I believe the HWH I am looking g at has a mixing valve I included standard but will double check.
 
Nov 18, 2010
2,370
Catalina 310 Hingham, MA
So just a pet peeve. It's not a hot water heater. No need to heat the water if it's already hot. Just a water heater. ;)
 

RoyS

.
Jun 3, 2012
693
Hunter 33 Steamboat Wharf, Hull, MA
Here is a photo of the thermometer for your water heater. Deep probe passes through T into hot water.
A69306E5-6B23-4D03-AF07-781F27B60E6E.jpeg
 
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DaveJ

.
Apr 2, 2013
344
Catalina 310 Niagara-on-the-Lake
Yes, George Carlin pointed that out...why would you need to heat hot water? LOL

And why put toast into the toaster....
Cheers
dj
 
Dec 29, 2017
34
Catalina 310 Middle River
Wanted to build on this thread for an issue I’m having with our water heater, notably the residual smell of marine anti freeze. I do a 2-3x flush of the system when I launch in the spring, but it the smell coloring seems to linger. In looking at the system the only thing of concern is this connector and the discoloring. My system is a Seaward F-1100-W. Any thoughts would be appreciated.
911F30C9-B192-4A7D-BAE8-04A2284BE550.jpeg
 
Nov 18, 2010
2,370
Catalina 310 Hingham, MA
Wanted to build on this thread for an issue I’m having with our water heater, notably the residual smell of marine anti freeze. I do a 2-3x flush of the system when I launch in the spring, but it the smell coloring seems to linger. In looking at the system the only thing of concern is this connector and the discoloring. My system is a Seaward F-1100-W. Any thoughts would be appreciated. View attachment 178186
Don't put antifreeze in the water heater or tanks. Drain them and put antifreeze in the hoses. Buy the bypass kit and the pump winterization kit. Makes your life easier.

Otherwise keep flushing.
 

RoyS

.
Jun 3, 2012
693
Hunter 33 Steamboat Wharf, Hull, MA
Or drain everything and do not add antifreeze anywhere. I simply drain, discard filters, and remove the mixing valve from the water heater. I have not put antifreeze in my fresh water system for decades. In the spring I install the mixing vlave, shock treat overnight with 1-1/2 cups of bleach, flush everything and install filters. Works for me.
 
Sep 29, 2008
1,784
Catalina 310 #185 Quantico
We put a bypass on the water heater, plus we use very cheap rum to winterize instead of the pink stuff. Usually two 1.75liter bottles do the trick. The water system gets pickled all winter long.
 
Jan 17, 2013
348
Catalina 310 St. Simons Island, GA
Exciting day today removing the fuel tank and water heater. Water heater was not a big problem but the fuel tank was a little tricky. I knew from this forum that it would be necessary to remove the propane locker but my locker was impossible to remove. Factory must have used an entire tube of silicone to seat it because removing it would just break it. So the guys I hired and was working with de ccx ided to cut the bottom off and will reattach it and fiberglass it back into place. Pictures attached. Also learned that the fuel tank was made by Skyline Industries in Nov 1989 and was only 17 gallons! So much for boat specifications! Hope to get 20 gals from the new tank when it is fabricated.20200429_135038.jpg20200429_135047.jpg20200429_114213.jpg
bob
 
Nov 18, 2010
2,370
Catalina 310 Hingham, MA
Exciting day today removing the fuel tank and water heater. Water heater was not a big problem but the fuel tank was a little tricky. I knew from this forum that it would be necessary to remove the propane locker but my locker was impossible to remove. Factory must have used an entire tube of silicone to seat it because removing it would just break it. So the guys I hired and was working with de ccx ided to cut the bottom off and will reattach it and fiberglass it back into place. Pictures attached. Also learned that the fuel tank was made by Skyline Industries in Nov 1989 and was only 17 gallons! So much for boat specifications! Hope to get 20 gals from the new tank when it is fabricated.View attachment 178322View attachment 178323View attachment 178324
bob
Replace that exhaust hose while you can and secure it better with a higher hump.
IMG_20190510_094130045.jpg
 
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