Hi Mark
I still remember your search for "What is this?" a few months ago!
I am glad that you were able to find what it was and it looks very good - your scratchbuiding 

A real lucky strike for your happiness was the fact that you could found several of them to take pictures -you're a lucky guy!!!!!
It looks like you will have to make two of them, so I guess it is a good exercise 

Have you find out how to make the floatation buoys?
Perhaps blue styrofoam? Just a hint 

Congratulations on an original model/dio that will come out of your work (for sure!!).
Keep us updated on your progress, please!
Skipper