I was a light infantry mortar section fire direction computer in both the 9th Infantry Division and the Berlin Brigade in the 1970s and early 1980s. We used Goats as mortar carriers and as one of only two sergeants in the company with no troops assigned I was the (additional duty) Motor Sergeant in both units. As it's been since about 1980 in West Berlin since I floated a Goat my memory is a bit fuzzy but the TM is a pretty good starting point for you.
If memory serves (but the TM will confirm or deny) you can float with any two of the standard accessory kits (IE winch, MG etc) but be cognizant of balance. A winch and MG add a fair bit of nose end weight and the low free-board is already kind of strong pucker factor without them. Nearly empty fuel tanks can add some flotation but may effect balance.
Make sure that you don't have the cab on it. You would be far from the first drowning victim trapped by one. If you MUST swim with the cab be sure and strap and not bungee cord the door open or remove the door. A bungee cord won't hold up to the water trying to push the door closed.
In addition to all the other things covered I'd advise that you don't wear heavy boots. They can get hung up in the pedals while you are trying to bail out. We also used to ditch the seat cushion to make rolling out of the cab easier.
Run it into shallow water first to check all the lower hull openings like axle and drive line seals before swimming it. The first time you float it on any given swim attempt I'd advise having a stout tow rope hooked to the pintle and run it slowly into a very gently sloping entry point (preferably with a stone bottom and not sticky mud....) until you are floating and staying afloat. Have the recovery vehicle on firm ground with all axles engaged and and alert operator that you trust with your life-literally trust with your life. If you get into trouble you will still have your head above water, be able to pop the gear shift into neutral, kill the engine, signal your tow vehicle and get dragged out. Remember that a Goat filled with water is a lot heavier than an empty Goat so be sure that your tow rope and recovery vehicle can handle the load.
Put enough water into the hull to test the bilge pump before swimming. And be sure that any pump hoses and seals aren't dry rotted. After all, you baby could be pushing 50 years old and those parts aren't exactly high on the routine inspection and replacement list.
And be darn sure that your tailgate is dead flat, that the seal is soft and not "dead" and that it makes a good seal all the way around. A leaking tailgate will sink you faster than no drain plugs-it's a lot bigger opening. We used to fill the carrier with water to see if the seal was OK.
Lastly, pay attention to the TM for approach and departure angles. It doesn't take much of a slope to turn a Gamma Goat into a submarine. Like an M113, a Goat has so little free-board that it is easy to drive one right to the bottom of the pond (or have one fill up on exiting) on a too steep slope.
Well, enough of my rambling....
Lance
