The big hose that connects from the C drive to the hull is open to the sea. Be careful if you play with that.
You would only get sea water if this is leaking.
If your C drive is like the one on my Yanmar , the big bracket is held on to the C drive with 4 bolts. There is no oil there.
Check the hoses from the expansion tank of the C drive.
If all is good then you probably have a leak from the very large lip seal on the C drive . It is in the sail drive facing the engine. I would look under the sail drive towards the engine and see if there is any evidence of oil leaking there, If so it would probably be the big lip seal. To replace that lip seal you would have to move the engine forward and disconnect the coupling from the C drive from the coupling/transmission.
I just replaced that lip seal on Kimberlite.
Kimberlite Amel Super Maramu #376
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Saturday, May 27, 2017 2:26 PM
Subject: RE: [Amel Yacht Owners] Oil leak on the "c" drive
We have eliminated the oil from the engine, which was my first choice of source. We do have to fill more oil on the reservoir above after ca 100 h.
Will see if the allen screws are all tight and if it breath from the oil reservoir