If you liked that through hull, you'll love this one for the sink drain;
It had a piece of painted marine ply for a backing plate, and gobs of 2 different color sealants on the outside flange. No big surprise that it rocked slightly.
I was using those old calipers to measure the OD for the new base.
Set on a G10 backing plate with black 4200 as sealant. I also used pipe dope with teflon to seal the tailpiece threads. I feel that I got the epoxy fillet just right on this one.
No comments on my proposed hardware upgrades (1" Bronze prop shaft, Vetus Bullflex Coupling experience, PSS Shaft seal, Vetus K75 Engine mounts) in the OP yet?
Right now, I am leaning away from the Bronze shaft because the PSS seal is stainless, and the seal and the shaft would be in direct contact. I believe that a stainless prop shaft is OK because there is a Nylon reducing bushing between the bronze prop and the shaft, and a rubber cutlass bearing between the shaft and the bronze strut. Make sense?