thru hull and seacock size for 1973 irwin 28.5

[dsi1333]

I'm looking for the size of the cockpit drain seacock and thru hull for a 1973 Irwin 28.5

[JimsCAL]

Measure it.

[rbrasi]

Measure the hole, figure out whether it's going to need a mushroom or flush head, and measure those for the flange diameter. I would venture to guess 1-1/4" with a 2" mushroom, give or take.