RE: Fin screw and dishes for isonic101
If your new Isonic 101 has the large oval counterbores then all you need is one screw, one SS flat washer, and one rubber sealing washer for each fin screw.
Take the screw and install the SS flat washer, then slide the sealing washer on the screw below the SS flat washer.
Install the fin and screws (short screw goes in the front if you have different length screws) and tighten them up.
Your fin will now be installed tightoly and sealed well to give you maximum performance.
The large white rubber "dish" was not really supposed to be shipped with your board. It's designed to protect the sailors feet, the foot of your sails, and your boom arms from the sharp corners on the hex head fin screws *bd used to use.
Hope this helps,