Cortez,
Marina
San Carlos and the adjacent Marina Seca (dry storage) are first class operations. They will transport your boat on hydraulic tractor
trailer from the marina to the
work or
storage area. Very professional operation. Their quality of work for bottom painting, barrier coating, etc. is very good, but you should expect stateside prices. You can also do the work yourself.
There is a
marine supply store close by, Star
Marine, and they have or can get most of what you would need, including rope!
There are also at least a couple of machine shops / fabricators in Guaymas about 12 miles away. I have used Hernandez brothers in Guaymas several times, and the work was excellent.
On the other side of San Carlos is Marina Real. They have a similar operation. Their slip prices are a bit lower. We have stayed at both
marinas, and prefer Real for their price. They are a bit N of town so a car would be very handy.