the proteus is the AHC. it's either a standalone one with a LARS (winch), all sold by DPDW, or they can adapt a proteus to the winches their customers already have installed on their vessels.
here are pics of two LARS (winches), a 3000M and a 4000M one, each installed on the "swordfish", a brand new ship built for veolia environmental, NYSE: VE: http://finance.yahoo.com/q?s=ve
this post is the first of several in the thread, so scroll through to see them all. the 3K meter lars is bright blue, the 4K meter one is grey:
AHC and Proteus are both the same thing. AHC is the generic term. Proteus is a trade name for DDI's brand AHC. But I think the Proteus may become a class of it's own. They also call it an "Active Heave Compensated in-line winch system".