I am mounting a Humminbird heading sensor to the front of my deck.

Because I don’t want wires exposed from the heading sensor to the back of my Humminbird unit, my plan is to drill a hole right through the carpet/deck and run wires in through hole behind my graph mount.

I plan on using a step drill bit to make the hole the size needed.

My question is, will the carpet start to unravel when I drill through it?

I don’t want it to catch and pull a whole string up through my carpet.

Anyone do this themselves? Tips?

Yes, the carpet will unravel. To avoid, drill thru the carpet with drill in reverse, once you have a hole in the carpet, switch to forward to drill on through. I wouldn’t use a step drill.

I cut a small x in the carpet, lift edges and put bit in place, drill hole.
trim the carpet back or just push in the hole if not using a grommet.

using a step bit will help a lot.

plus one on not using s step bit... use a forstner bit.. much less risk of poking a hole in someplace you don't want to.