Metal plug/bolt on strut drowned!

[Adnaan]

I was diving on my prop to check and replace zincs when I noticed two little bolts/plugs with Alan wrench heads sticking out on each side at the bottom of my strut where the prop goes through it. In the dark and murk, I thought they might be attachment points for more zincs. As I undid the second one, I lost my grip and it sank to the bottom.

Obviously I want to replace it as soon as possible, but how urgent is it? Don't want sea life growing inside the strut... What are the plugs for, though?  What are they called, so I can order a replacement?

I was anchored out. Sailed off anchor, but had to run the motor to get into my slip. Didn't notice any ill effects. Please help me not damage my prop shaft beyond repair!

Cheers, lads.

Adnaan

[Dolce_Vita]

I believe these are setscrews that lock your cutless bearing in place.  Looks like they are standard 1/4" setscrews, the same as those used to lock stainless steel tubing in place in fittings, like on a bimini.  Sailrite carries them.  https://www.sailrite.com/Set-Screws-Stainless-Steel-Replacement-for-Fittings

[Rusty Pelican]

OOPS,
You just lost the set screw for your strut that holds the cutless bearing in place.
There are 2; one on each side.
Depends on your strut if you can skate on zero or 1 set screw.
boat model

[Adnaan]

Thanks for giving me the name. Hard to Google the damned thing when I didn't know what it was. I'll order a replacement and avoid motoring til I get em back in.