Using the fording kit, a jeep could operate for more than 15 minutes while under a foot or more of water. It was published in the January 1947 issue of Popular Mechanics.
This December 1943 article from Popular Mechanics highlighted an early attempt at a water proof jeep. In this case it was accompanied by a waterproof trailer.
Look it’s Nessy! Looks like it took a few years to figure that exhaust doesn’t smell good and to figure out you definitely need a snorkel. Can you imagine the sweat you’d have in that heavy rubber suit. Whew, it would be alright for winter but still with the sweat in there with you it wouldn’t take long before hypothermia to set in.