Sub contractors rates?

In south Florida, anywhere from $80.00 to $120.00 per hr. depending on the trade

Hmm....Paying peanuts and getting top quality is never going to happen. Cheapest is not always a good bargain, also how busy are they in the season? Ask around local boat owners for what rate they pay and the level of service they receive.
My business partner and I have been doing it a very long time, we pick and choose our clients, not the other way round.

Were @ $80/hour hands on.
Out of this; shop rent, capital Van and truck, loads of insurance (corp and health), 3 work boats.
Then continued education and licensees.
We have bacon on the plate (sometimes bologna).
We do FL east coast deliveries and local towing. More money working on the docks though.

Currently 3 weeks out.

When folk see that hourly rate their eyes roll back.
They just do not understand the expense to put us on site with the tools and support to do what they need.

If I don't retire again; I can see 2019 or 2020 we will be near $100.00/hour hands on.

$120.00 per hr. & up. Last yr. paid $135.00 per hr. for a new install of a 65 HP hydraulic thruster / PTO pump and plumbing on a 30 meter vessel in Stuart, FL. Much to my consternation the contractor would send two techs every time they came to the vessel for a total of $270.00 per hr. When you figure a week of billable hours $270 x 38 hrs. being a tad above $10,000 dollars plus the 15% the yard is going to tack on for allowing the sub to work in their yard this quickly becomes untenable. When I brought this point up that it certainly doesn't take two guys to measure a couple of short hose runs from the reservoir to the PTO pump the response was to drag their feet for future scheduling the completion. This sub is a well respected outfit in South Florida with a great reputation in the industry but good ,well qualified specialty subs are in such high demand that they've become primadonnas and as fish says, they (subs) can pick and choose their customers rather than the other way around. In other words, they've got you by the shorties...

For most things labor rates seem to be just shy of $100 an hour in miami and ftl whether mechanical, air con, hydraulics, etc...

I got really ticked off at my air con contractor last week when they charged me $160 to come look at a problem on the watermaker then 9 hours of labor to replace the HP pump, a task that took 4 hours, plus maybe an hour of travel time.

A few years ago i had a similar issue with another air con company. After chasing 3 hours of missing labor, i was told that the clock started running when the guys showed up to work at the shop, including stocking up the truck. And then the two of them stopped for breakfast on the way...

And then you have those who cant work alone and bring a helper even though the two of them cant fit in the spot where the equipment is installed...

BOAT. Bend Over And Take it.

Service managers are under pressure to insure that all of the techs on payroll are billed 8 hrs a day and what used to be billable time "pothole to porthole" is now like you say, Billable as soon as they punch in on the companies time clock. I was told that a particular large electrical company in Ft. Laud. service dept. meets every afternoon before quitting time for the techs to get their next day assignments so they can sleep on it and think of what they need parts wise on the truck next day etc. Fair enough but travel and svc truck stocking should be billable @ half rate maybe? I realize that costs to the company are high but for some reason outside of insurance costs & real estate, I cant see why labor rates have gone up 80 % in the last 25 yrs but the techs rate of pay has remained rather stagnant @ the $18.00 dollar an hour to top of the mark $25.00 per hour? This is what leads to good techs hanging out their own shingle after a few yrs. It costs these companies much more to hire & train a new employee rather than pay their existing qualified employees a livable wage for the skilled labor they perform.

Bradford charges $82/hr for general labor and $95/hr for skilled labor; specialty trades such as electricians, engineers, hydraulics is $95/hr.

Right on par with Derecktors Shipyard although neither would be classified as subcontractors per the OP's question.