underfloor fuel tank upgrade advice

Hi guys, I've recently started doing alot of longer range fishing trips and am investigating the possiblity of upgrading my boats underfloor fuel tank from 265lts tank to something around 450lts.

My boat is a 7.5m hardtop ali, twin 150hp the current fuel tank in the usual spot  (aft area running port to stb). My ambition is to also use the tank upgrade to also improve my boats stability whilst static and underway if possible. My intiatal thought is to remove my current tank and put the new tank in the running along the keel up to about midships, to me this would lower the center of gravity whilst moving and fishing. and I'd like to have longitudinal kill tanks running each side of the fuel tank that are also floodable at rest (I understand that stability will vary as fuel is used, but my current tank I believe has limited stability improvements all together being down the back and running port to aft).

If anyone one has any knowledge / advice on this topic or can recommend someone to do the work, I'd love to hear it before I commit to the project $$$

 

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Feral's picture

Posts: 1508

Date Joined: 01/11/06

 I placed an extra tank in

Sun, 2018-09-16 22:26

 I placed an extra tank in between the bunks up the front .. Ive only used it on flat days but it does help lower the nose and slice water.. At the end of the day it can't hurt to do what your suggesting.. You've got plenty of power to push the extra weight and as long as its baffled correct it shouldn't make the boat rock around

Faulkner Family's picture

Posts: 17835

Date Joined: 11/03/08

 Have you thought about the

Mon, 2018-09-17 06:50

 Have you thought about the portable fuel bladders. Pack them away when you dont need them and can place them anywhere you like in the tub

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RUSS and SANDY. A family that fishes together stays together

Posts: 23

Date Joined: 23/11/14

 Thanks feral and faulkner

Mon, 2018-09-17 16:33

 Thanks feral and faulkner appreciate the feed back.

In regards to the bladder my main goal is to get as much use out of the underfloor area to free the deck up, including using the underfloor kill tanks I suggested to have cooler bags in them so I can go away from a massive esky on the deck. I have been using fuel jerrys but as mentioned I'd love to have it all underfloor.

My main concern is stability i dont want to compromise it, but I cant see how it would have a negative effect I assume it would be similar to a floodable keel on a crusher.

 

Theres just so much space not being used!!

Posts: 812

Date Joined: 09/10/06

 First thing l would be doing

Mon, 2018-09-17 20:18

 First thing l would be doing is going and talking to a reputable custom boat builder. 

Posts: 23

Date Joined: 23/11/14

 Yeah thats my intention

Tue, 2018-09-18 17:07

 Yeah thats my intention mate, just hoping to possibly get some real life experience from someone who may have done this mod prior and any things that could be done better if they had their time again.

 

Posts: 23

Date Joined: 23/11/14

 Yeah thats my intention

Tue, 2018-09-18 17:07

 Yeah thats my intention mate, just hoping to possibly get some real life experience from someone who may have done this mod prior and any things that could be done better if they had their time again.