This is a really interesting home made all terrain vehicle. This truck is apparently made to be a homemade crane to lift motors and parts, etc. They opted to make it run underwater too.
From their Youtube page NZ Offroaders describe the details of this rig:
A truck a mate built at a farm in New Zealand. Its an old school safari with a 3.3 diesel motor and a welded rear diff and PTO winch on the front with a number of pulleys so it can lift things eg Motors gearbox’s etc. Its one very cool machine and one of a kind and with Roy driving it will go some places haha