I remember getting out of the Navy too....
Here's some advice from a guy who EAOSd in 1989, but I'm sure it holds true today.
First, if you're still in, start making contacts now. Drive all of the Marinas. Ask the dockmaster if he's happy with his current service provider. Why? Why is he unhappy, or why is he happy? If his clients are happy, he's happy. It's no skin off his balls to tell you what you want to know, if he's happy he isn't going to recommend you, if he's unhappy he'll let you know why.
Have 3 months living expenses in savings for you and the family. This business will not come up overnight, and Spring is the busy time in the SE. Everyone wants to get the scabies off of their boat. Start now. You can start with a 12", a 4", and a 1 1/4" scraper. If you are going to do shrimp boats, you will need a chain with wooden toggles at each end to clean the keel coolers. You want to do Shrimp boats and commercial fishing boats, BTW.
I used to charge by the tank. It was $150 to get in the water, then $100 bucks a tank for the second through whatever. That was for cleaning, ropes in the wheel, pulling wheels, whatever you wanted me to do. If I had to go offshore because a trawler had backed over his gear, the price went up exponentially. If the weather was bad, the price went up exponentially for offshore work. Seems they never back over their nets unless it's blowing a gale.
Never turn a job down, unless it's really unsafe. Then, don't take the job in the first place.
Go get a drysuit. Marinas are full of poopoo. Shrimp boats are disgusting, crewboat crews will flush a brown trout while you're under the boat just to have a laugh. You will probably end up with an AGA and a tender unless you plan on using your 17/27/37. You can do it on scuba, I did, but I wasn't trying to make a living, I was trying to make rent in the winter. Beer money, etc. A compressor, gas distribution panel, and tender, just like you were taught is the safest way to go.
I can easily see spending $25-50 K to have a compressor, gas panel, comms, masks or hoods, etc. You can do it for less money. How old did you say your kids were? Should they be without a daddy?