CONTINUOUSWAVE

Good afternoon. I am restoring a 1968 Sport 13. This is my thisrd restoration of a classic Whaler. As I'm sanding the interior and dealing with the much loved "spider cracks" i am wondering:

Q1: what is the purpose of the circular cover in the bow, just ahead of the anchor locker? It is about 6-inches in diameter and sealed.

It purpose is bugging me to know. I'm sure someone here must know. Thanks

The feature of the 1968 SPORT 13 you describe is probably the SPRUE or a circular cover over the sprue. The sprue is the hole via which the liquid which expands into foam was introduced to the interior of the hull; as the liquid expands to become foam, and and expanding foam is expelled via the sprue.

SPRUE, noun: (https://www.merriam-webster.com/dictionary/sprue)
--the waste piece on a casting (as of metal or plastic) left by the hole through which the mold was filled;

--the hole in which a sprue forms

I figured it must be something like that...thanks, now I know.