Adding an axillary fuel tank information resources?

Swedefj40

Petty Officer 1st Class
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Jun 9, 2018
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203
My 22' cabin cruiser has a 189L (50 u.s. gallon) fuel tank and I need to bring at least another 75L (20 gal) of fuel to feel comfortable on some of my long overnight trips so I'm contemplating adding an additional fuel tank to the boat. Can someone point me in the right direction (online resource) for the proper way to do this (ie: coast guard standards etc.)? Thanks.
 

dingbat

Supreme Mariner
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Nov 20, 2001
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16,066
My 22' cabin cruiser has a 189L (50 u.s. gallon) fuel tank and I need to bring at least another 75L (20 gal) of fuel to feel comfortable on some of my long overnight trips so I'm contemplating adding an additional fuel tank to the boat. Can someone point me in the right direction (online resource) for the proper way to do this (ie: coast guard standards etc.)? Thanks.
I have a 94 gallon main and a 54 gallon aux tank on a 22’ Walkaround

Both tanks are mounted on centerline. One under the cockpit floor and other under the helm floor.

Both are accessible with removable floor panels.

Uses a two way selector valve to switch from one tank to another

The hard parts unless designed for two tanks, is to find a location to mount the tanks and the access covers
 

alldodge

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Mar 8, 2009
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42,054
Depends on how much room you have, and on a 22 foot cabin cruiser there probably isn't much. Some use bladder tanks so they collapse. Head out and after burning 20 some gallons, place in main, fold up and stow
 

Swedefj40

Petty Officer 1st Class
Joined
Jun 9, 2018
Messages
203
I have a 94 gallon main and a 54 gallon aux tank on a 22’ Walkaround

Both tanks are mounted on centerline. One under the cockpit floor and other under the helm floor.

Both are accessible with removable floor panels.

Uses a two way selector valve to switch from one tank to another

The hard parts unless designed for two tanks, is to find a location to mount the tanks and the access covers
My main tank is under the deck, directly in front of my Mercruiser v6 engine. There is a bulkhead forward of the tank which lines up with the back wall of the cabin above. My thought is to put the aux tank below the cabin floor on the other side of the bulkhead, directly in line with the original tank. I currently have storage compartments in this spot.
 

Swedefj40

Petty Officer 1st Class
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Jun 9, 2018
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203
Depends on how much room you have, and on a 22 foot cabin cruiser there probably isn't much. Some use bladder tanks so they collapse. Head out and after burning 20 some gallons, place in main, fold up and stow
Yes, the limited space is an issue. Storing 3 jerry cans in the v-berth is a pain that I really want to eliminate, not to mention the safety issues with transferring fuel from them to the main tank mid trip.
 

Swedefj40

Petty Officer 1st Class
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Jun 9, 2018
Messages
203
Here's a shot of the area I was thinking of locating the new tank. The hull is about 3" below the floor. The steps are lockers that need to be replaced this off-season. I was hoping to reconfigure this area and incorporate the tank.
 

Swedefj40

Petty Officer 1st Class
Joined
Jun 9, 2018
Messages
203
Anyway, I guess what I'm asking is for a resource to know what exactly are the safest ways to add a tank. How to tie it into the fuel system, etc.
 
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