We used it to launch, and we couldn't get the tongue extender pulled out on the trailer so the back end of the truck went in the water right up to the bumper! I was a little nervous but it ran fine after that -- no problems. We did buy their extra insurance for 9 bucks. Figured that was worth it.
We only need to move the boat twice a year -- to launch in the spring and put way in the fall. Renting is definitely worth it for us!
Tongue extenders are known to be a hassle when they rust. Some peopl avoid them for that reason. Just keep the thing greased and it won't rust. It's messy and you have to avoid touching the extender with your clothes when it's out, but it works. A neighbour of mine kept his lubed up with lithium grease, used it for years and never had an issue.
Trucks have a breather/snorkel hose that runs from the back axle up to the frame just below the underside of the box. In general, as long as that hose end doesn't go below the water it's ok.
If it does go below water, then water can go down the tube, get inside the differentrial+axle and eventually damage it.
If it was salt water, I'd rinse the brakes and wheels and body down with fresh water afterwards. A hand pump yard sprayer works well for that.
Yeah, for $9 the insurance is a no brainer, especially since it eases the hassle of dropping it off.
