TFL Expanding Hole Opener Reamer 0-14mm For RC Model Body

TFL Expanding Hole Opener Reamer 0-14mm For RC Model Body

This is a great tool for all rc vehicles. 

But for boats, this is extremely valuable. Use a small drill bit to drill the first hole. Then use this reamer to bring the hole up to a diameter a bit smaller than the diameter of the fitting you are installing. This helps to insure a water-tight hull.