We spent two weeks in the Mazatlan area at Marina Mazatlan which is just north of town. We are not seeing derelict boats in marinas down here, the dock pricing (in general costing twice what we pay for berthing in California) seems to discourage any poorly kept vessels from lingering.
One afternoon we took a dinghy excursion of the waterways surrounding the marina area with Dale and Dena from Double Dharma and our new friends Gary and Nadine from Harlekin. We saw many very nice waterfront homes (one would almost think that they were touring some of the canals around Fort Lauderdale), interesting wildlife including various birds, iguanas and jumping fish, and several places along the estuary where you can stop for eating/drinking.