Baby bob on a old version mast head...
The bob comes with a kit # 30116. This is an instruction and 4 short screws.
http://static.hobiecat.com/2010_archive/support/pdfs/30116.pdf
<<2. & 3. Hobie 14 and Hobie 16 without Comp Tip Mast Head. Tools required are a number 20 drill, a 10-32 tap and a drill motor. Place the Mast Float and Bracket over the mast head casting such that the centerline of the float is perpendicular to the center line of the mast. Make a mark on the casting at each of the 4 holes in the bracket. Remove the bracket and drill and tap the 4 holes. Caution: Avoid drilling into the sheave if possible. Using the 4 each 10-32 by 5/16" screws and lock washers secure the Mast Float to the mast head. The Hobie 16 mast head casting is narrower then the Hobie 14 and it will therefore require that the ears on the bracket be bent in.