Re: '78 Ebko Lebaron - Therapy
OK, here's my engineering side on your tank issues...even though I don't hold any kind of engineering degree [I can spell it though...
] or even play one on TV...
First off, take into account that you don't want solid hard substance contact between the tank and hull...
So, get some kind of rubber, like I mentioned before... cut some strips to place on the bottom of the tank...check to make sure of your installed height, after that...then use rubber strips everywhere else to fill any gaps between the sides and the deck...don't make it so tight as to make it like a solid mass...
The reason being, when the tank has fuel in it, the fumes will want to expand and contract depending on temperature and how much fuel is in there...
You want a snug fit, but not so tight that the constant expansion and contraction, plus flex in the hull while hauling butt on the waves, could cause a stress fracture...some fuel tanks can change dimensions by as much as 1/2 an inch or more...
The idea of foaming is not bad, but if you don't keep a ton of weight on the tank while pouring the underside of it, the foam could easily raise the tank above your deck height, which would cause you to shave it back down to the correct height...then again, you could screw the tank down, pre-spaced from the bottom, so it doesn't move...
Don't get me wrong, I really don't know what I'm talking about, but I have worked with fuel tanks and expanding foam before, not necessarily together, and know that each of them have their quirks...
If you notice that older cars just had the fuel tank hung underneath the car with a couple of steel straps with some kind of rubber insulation on them and modern cars use fuel tanks that are made of a polyethelene type plastic...this was all done so they can expand and contract...
That is another reason some boat manufacturers foam their tanks in...the foam has a little give to allow the expansion and contraction...others just use either a plastic type tank or the same type of strap set up that they use in cars...
Then again, some are even rigidly mounted, but usually with just a couple of mounting tabs attached to some sort of structure, but the rest of the tank is free all around to expand and contract...
Boy, oh, boy...I hope this long winded babble is of some help, cause by now I am not sure if it is...:facepalm:
I guess that was my 2?, plus or minus a nickle...
Later,GT
PS- editing for obvious reasons...by the time I got done jibber-jabbing, you had already foamed everything in place...Very nice job...that looks like it will work just fine, just don't put anything too solid between the deck and the top of the tank...
