Best way to drill a hole in fiberglass transom?

[Feydakin]

I finally got the engine mount trolling motor put in the Four Winns. The cable is plenty long enough to run over the top of the boat, but I want to run it under the swim deck somewhere next to where the upper unit enters the boat to clean things up and make it safer to use.

I figure I'll need to use a firewall grommet for a seal, but really have no idea what is the best way to drill the hole and then make sure it's sealed well.


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