the southern one is behind the Hotel Presidente and is very shallow ..only scuba and small fishing boats
the other one is north of the "bay" ....and should be ok for you. But it is also somewhat crowded, especially when their is a fishing tornament going on.
They have two large Cruise ship piers
south f the ferry piers. There is plenty of room on the inland side of the new pier, but I doubt that the cruise ship people would like you there.
It doesnt look too good. Try to find the harbourmaster email and ask him before. I will bet that you have to anker in the "bay" in front of Charly and Charly...
There are two boats ankered there from the sailing center in Coz 20 and 30 feet all year long. Its pretty unprotected I am afraid but the holding should be pretty good.
Again check with the harbourmaster first.
I have a pic of the rental boats ankered there
find out the email from the harbourmaster from.. www.seaurchindive.com Tell Isidro I send you. And if you go diving , definitely go with him. !!!! He is the best.