Transom trailing edge

Some sources indicate a rounded trailing edge of the transom produces less drag. Another mentions having a chamfer, starting 1-2% of the beam from the trailing edge of transom (about 2 inches on boat in question, 8 ft. beam). Is this information correct? And, if just radiused, what radius? Thanks, Ron

What kind of boat, how fast does it go?
A sharply defined edge is great for planing speeds, but for many slower boats, it doesn’t matter, or the transom may be above the waterline anyway.

I should have noted; Sailboat, slow. The transom edge is mostly in the water, but probably more so when heeled. Thanks for the reply.

For "slow" (i.e. 5-6 knt) displacement hulls it depends on the sailing buttock lines. The buttocks at the transom, in sailing condition, should be shaped to stabilize the boundary layer growth. If the buttocks are too steep, then rounding out can help. If the buttocks are too flat, the they should be cut off square like a planing vessel. Heorner discusses this in Fluid Dynamic Drag.