Drains on 1979 21-footer

[Red Boston]

Q1: where do the two white drains go that are below two open drains at the stern of a 1979 21-foot hull?


BACKSTORY
I have purchased a 1979 21-foot hull that has two engines. A day after the boat was launched, water accumulated on deck close to the stern. I pulled out the boat from the water. I removed the drain plug. A lot of water came out.

I am not sure what [drain] plugs are missing. The stern has two open drains and below each of them there are some white drains.

[jimh]

Q2: where is drain from which you removed “the drain plug” and from which “a lot of water” flowed when the boat was hauled out?