Surely those little loops youv got your lange fastend to wont hold that??
i have them in my van and they dont seem strong enuf to hold a tank.
Dave
THEY'RE NOT

Any sort of shock and they'll break, they're only designed to be luggage restraints. You should put eyebolts down through the chassis and if the hook of the strap won't go through the eye, use some BIG "D" shackles.
Also the straps should go from the rear eyebolts over the TOP of the tank, then to more eyebolts in front of the tank, also bolted down through the chassis. Those straps look to be about 5 ton, but they're useless if they're not anchored properly.
The way you've got the straps going under the tank, there's nothing stopping the back of the tank coming up and over and smashing into you

For your own and your passenger's safety you should sort it before you drive anywhere.
Cheers,
Ian