"Denis M" wrote

When I look at the stern I saw what appears to be an hydraulic crane. If
so why was that design selected in lieu of a fully articulated hydraulic
crane seen on navies frigates?

It's a hydraulic A-frame which works better for handling the gear deployed
on oceanographic vessels fora lot of reasons I don't have time to go into
now. I put an articulated crane on my first oceanographic vessel years ago
and she now has an A-frame.

--
Roger Long