Any idea where to get them?

I would think someone with a 3D printer could duplicate that pretty easily.

Why don't you get your guy to do the SeaDeck or whatever brand you are using there so it matches the floor?

Did u ask your son? Lol I do agree some plastic and a cabinet guy could make them.

StarBoard, table saw, router.

I am pretty sure the original pieces were some sort of an acrylic, which can be a pain due to the brittleness. We had some made and the came out good but were not perfect

These may work for you
https://www.marineindustrieswest.com...7&productid=88

if you order them now, you should see them buy January 1st 2022. Place is painfully slow if parts aren’t on the shelf already.

if you have one of them, any acrylic shop can reproduce them. all they need is a template. most good ones have cnc routers in house.

Like someone said before those would not be hard to 3D print. Likely printed in red ABS with some yellow inserts also made of ABS. I'd be happy to print a set of them for you. I have multiple printers and have done similar items for boats and cars.