Need advise on tank size

[michaelsen]

I am about to have a aluminum tank custom made to fit my boat. I will put in the back up against the inside of the transom. A 3 ft lenght would work good. That would give me about 1 ft. storage space on each side of the tank and that would give me a 23 gallon tank. I could make it 4 ft long and get 31 gallon, or even longer. How much will I need? Can I make it too big? I have no clue. It's a 18" bowrider and I have a Mercury 115hp (inline 6. It will be used for day trips on the river, tubing and fishing and smaller trips off-shore.<br /><br />Regards<br />Mike

 

[si-man]

Re: Need advise on tank size

I would watch where you put the tank i'm no expert but you want to try to keep some or the wieght away from the back of the boat. I have an 18' with a 190hp 4cyl 3.7 litre i/o and my tank is almost in the middle of the boat and I think it's abt a 30 gal tank

 

[michaelsen]

Re: Need advise on tank size

Unfortunately the only place where I have room for a tank is in the back. I just wish I knew how much gas the old 115hp is eating <br /><br />Regards<br />Mike

 

[si-man]

Re: Need advise on tank size

it's an i/o???

 

[michaelsen]

Re: Need advise on tank size

No, it is a outboard...

 

[mako]

Re: Need advise on tank size

The first thing that came to mind is the extra weight. What did you have for a tank before and where was it located? Most boats I've seen have the tanks located more to the center but I was just looking at a Monark boat with the tank built right into the back like you want to do. It was an 18 ft. center console, I'm not sure of the capacity. You should take the boat out with portables and see how much fuel is used on a typical day, and a go a little larger. Also there are some companies out there that have pre made tanks, Todd is one and they are located about ten miles from me. I think they make aluminum and the plastic ones too. If your getting a good price go for it. Gas weighs about 6 lbs. a gallon so if you go with a 31 gallon tank that would add about 186 lbs plus the weight of the tank, compared to 138 lbs. for a 23.

 

[MIKE F]

Re: Need advise on tank size

I don't know, what type of boat you have, but don't you need, room for a bilge pump, back there?

 

[michaelsen]

Re: Need advise on tank size

Do I need a pump? I've had two smaller boats before, but never any pumps.<br />I have tried to look around for a picture of the type of boat I have and I found this http://www.fun-a-float.com/bwrdr16b.gif . It's a typical tri-hull from first in the 70's. I will have single seats instead of the double seats on the picture and then I will make a bench in the back. The fill and vent holes is in the back, so the tank must have been there originally.