18SF tank size
 

Just yanked my tank out today and was surprised to find that it was only two thirds the size it could have been.

https://lh3.googleusercontent.com/-G...2/IMG_1257.JPG

Did SeaCraft have any particular reason for this in the 18 footers?
Would it be detrimental for me to have a tank made to accommodate the entire space? I imagine I could pick up some range that way, but also some weight.
It is down low though.

Anyone out there who's rehabbed an 18 want to weigh in?

And does anybody have a favorite tank manufacturer here in the North East?
I know I could get one shipped from Florida pretty easy (Sunshine, RDS, Florida Marine) but anybody recommended up here in the Cape Cod vicinity?
I think New England Propeller builds tanks but I have no direct experience with them.
Just looking for opinions.

I used Sunshine and very satisfied

I would highly recommend Eric Kent at KentFab; I believe they are now in Pembroke, MA.
Very high quality work and a nice guy to do business with on top of that. Good luck with the project.

If you plan to go with new motor technology ,you won't need extra capacity. I would use it for storage,or move tank forward to counter the added weight of 4 stroke or maybe a bracket if you are thinking of going that way with it. Food for thought.

I bought a plastic tank at a place in Portmouth RI, I can't think of the name offhand but someone else may chime in.They had many sizes to choose from.
P.S. I will be calling you soon to set up a time to get the footrest to you.I will probably be in Chatham next sunday.

I bought a 1975 18 SF in the spring & had it shipped from Louisiana to the North East. The boat is in unbelivable shape & there is no soft spots or cracks anywhere. The two brothers I bought if from took very good care of it & they kept things very simple , no unnecessary holes to deal with. Anyhow, they replaced the fuel tank with a plastic one & they provided me with pictures of the install.
Its a 40 gallon tank made by MOLLER , fits just right in the coffin box of the 18 SF & measures 60"L x 23" W x 7.78 " H in the middle & tapers out to 6.87" H on the ends. Part # FT4032 . The top of the tank is flat & the bottom is chamfered or beveled @ the sides. There is an 8" flat section on the bottom of the tank in the middle where it measures 7.87" high & the ends or sides that are beveled on the bottom & measure 6.87" high are 7'5" wide on both sides.
Hope that helps.

I have a 77sf18 that I'm gradually restoring. I did the fuel tank 2 yrs. ago and found the same undersized tank that you did. I looked locally for a fabricator on cape, but settled on Speedy Tanks in NJ. I gave them the measurements and they had a custom built aluminum tank on my doorstep in about a week. I don't recall the exact dimensions, but I think I went from 35 gallons to 43. Because the extra capacity is forward it should improve your COG I believe, at least when full. I do agree with Sidelock's comment however, that you probably don't need a lot more range on an inshore boat with efficient power.

You should have had a 30 gal tank when she left the plant in Miami. THE 80'S 18SF's were 47 gals originally. Im not sure about the space being bigger than the tank in a Potter 18.

Danny my '78 I'm pretty sure had a 47, may have been an option

Measurements on the tank show it to be about 30 gals, which is in keeping with the factory specs.
I was just surprised to find about 18 inches of foam filling in a cavity in the tank coffin ahead of the tank. A much larger tank could have been installed but wasnt. I'm guessing the coffin mold for the 18 is the same as the 20, and they just put a smaller tank in because it was a "smaller" boat.

I think I'm going to go with the plastic Moeller tank that sidelock and sceptre20 refer to.
Holds slightly more gas than stock, fits in the coffin perfectly without any mods and is about half the cost of a fabricated aluminum tank.
I think it will suit my needs perfectly.

Like I said I think 47 was an option and would have filled it up, although blocking it to the front would help on weight distribution

Mine was replaced about 9 years ago. Don't know what size came out of it, but, it currently has a 35 gal. tank.