I know it was mentioned here already, but I can't stress the importance of a dive mask and dive knife enough.
A few years ago, the tube rope got tangled around the drive shaft. I spent over a hour going under the boat and pulling the rope out (without a knife or mask). This is what sealed the deal for me for always carrying these 2 tools on board.
Now fast forward to yesterday. While cruising across the lake at 26 mph to go eat at one of the local restaurants, the boat slowed dramatically, and I could tell we had something in the prop. I immediately shut it down, and knew I was going to have to get wet. I donned my mask and jumped in. What I found was a long blue rope tangled around the drive shaft. I pulled up on the line that went into the abyss, and wound up pulling up someone's anchor they abandoned.
Luckily I had my dive knife on board. In about 20 minutes, I was able to cut the rope off of the shaft, and get to dinner and a cold beer.
I would like to thank Russell for circling like a shark and calling me 'Scuba Steve'. On the bright side, I now have a 28lb anchor to sell.