What’s this?

I’m just trying to figure this out.  My best guess is that suspended from a 20-ton capacity A-frame is a set of underwater hands, a sampling device, a seafloor-drill, all tallied 14 tons of instruments  and tools in a seafloor frame. 

I can’t tell you the division of labor between the equipment lowered/raised through an approximately 10′ x 10′ moon pool by the 90′ derrick and the seafloor drill.  My guess is the the seafloor drill can function at great depth.   Note the Panamanian registry.

All those portlights . . .   relate to the 50+ crew the vessel can accommodate. 

The helideck . . . 62′ diameter, can accommodate helicopters of the Bell 412 type, i.e., up to about 3.5 tons. 

If you didn’t click on the equipment and specifications link earlier, my source for all I pretend to know here, you can click here now.  Since she was anchored in Gravesend Bay yesterday, the tide pushing her stern toward shore, I managed to get my first photos of her stern.   I have seen the vessel, working to amass wind farm bottom terrain data, several times since January 2018.   With the green light to transform South Brooklyn Marine Terminal into a dedicated wind farm construction hub, I suspect some interesting and exotic vessels will be transiting the Narrows in the next few years.

All photos and attempted interpretation, WVD.

Maybe a reader out there can explain how this equipment really works and what super-detailed examples of bathymetric chart of the New York Bight look like.