Re: bravo 3 duro prop
The outer nut is 1 and 7/16" and you can find a 1/2" drive socket if you look real hard. But a 3/4" drive socket in that size is real easy to find at Farm and Fleet or Lowe's, for about $15. Mercruiser also sells their tool for about $35-$40
The inner nut is 2 1/4" and the deep socket is a Mercruiser only tool. (1/2" drive) You can make one out of a semi-trailer wheel bearing socket, or fab one yourself, or buy the Mercruiser wrench online for about $60 (I think. And Iboats might sell them). There is also a hand wrench that guys have. I think it's available at a place called properthing.com or something like that.
I hope you have just bought that boat and that you haven't owned it since it was new and have never removed the props! And I really really hope you haven't kept in the water every summer, cause you are not going to like what you see, when you get them off. The rear bearing carrier is what corroeds on a B3 drive, and 7 years slipped in the water is more than enough time to ruin one!