I was keen to fit an underslung LPG tank to our van to free up valuable interior space, and to me it seems safer keeping the gas outside the van. 

I opted for a Gasit 20L easyfit tank. This makes fitting the tank really easy as it comes with welded feet that simply need attaching to the underside of the van to ensure the tank is sat at the correct angle. This is the tank:

It comes with all of the fittings pre-installed and pre-tested, with a heavy duty plate covering the valves:

Gasit do sell mounting kits for other vans, and a generic mount designed to attach to the floor, but it seemed easier and cheaper just to make my own. I paid around £10 for a metre of angle iron and a meter of flat bar from my local fabrication shop.

I made the mounts out of 3mm angle iron with a piece of 3mm flat bar lap welded underneath the angle iron (overlapped by around 3mm). Both the angle iron and flat bar were 25mm wide and cut down to match the span of the feet (180mm):

 I opted to lap weld to give a bit of clearance under the floor supports that the mounts will attach to:

The mounts then bolt onto the sides of the 2nd and 4th floor support from the front with 4 M8 bolts:

Hopefully in this picture you can see how lap welding the joint allows the mount to sit inline with the bottom of the floor support:

The tank then gets gently jacked into position and bolted to the mounts:

As I still have the van on the rollover jig I also got some pictures with it rolled over:

Gasit also sell the fill point which I’ll be fitting just in front of the rear jacking point.