Thrugh-hull drill size

[phorvati]

Grocco installation says
STEP-1: Cut a hole through the hull
and backing block slightly larger than
the thru-hull fitting OD....

What is slightly larger?
I have an old datamarine transducer hole that is 2-1/16" in diameter. I want to put a 1-1/2" bronze grocco scoop strainer. Grocco does not say what it's OD is. any info on that would be great. I looked up the OD on a 1-1/2" NPS pipe, and it says 1.9".
So my question is....is 2-1/16 slightly larger or too big in comparison to 1.9"?
Thanks

[model 10]

5200 will fix that. If my math is correct, that's only like .0080 on each side.

[phorvati]

Its actually 80 mils or 0.08". which translates to 40mils or 0.04" void around the through hull.

[model 10]

Originally Posted by phorvati

Its actually 80 mils or 0.08". which translates to 40mils or 0.04" void around the through hull.

Dang! an extra 0. I still don't think there is a problem.

[phorvati]

After further inspection I had a bigger problem. 5200 was used to fill a void created after removing balsa around the hole in the sandwich structure. after I took that out, I had no choice but to pour thickened epoxy. i waxed a 1-1/2" fitting and left it in there, then poured epoxy in the void and gap. Now the hole is snug with the fitting and there are no voids in the walls. Everything filled quite nicely.