Benny,

I found this question/answer:

LUNATIC: Just finished my DD and was wondering how you are securing the fuel tank... I have plenty of foam wraped around it
for a tight fit, but I want more security...
Sport Flyer: I put J-hooks into a hardwood rail on each side of the tank and secured the tank with an elastic.
phillybaby: i cut out a strip of plastic and screwed it down on top of the centre ribs
jlong34016: Velcro.

Edgar