I'd 2nd the course work recommendation. The do (at least mine did) teach the subjects you will be tested on. But, at least in my course it went into more than just teaching answers. In the class room environment
we had a wide range of experience. A couple had allowed they license to expire and were starting from scratch but knew enough to teach a class on their own. We had real life experiences that drove in some of the class room material and made if far easier to remember.
The Map work is generally the most difficult and don't be too surprised if some are a bit tricky. In our school
they had 4 different test for each section. As I recall
they had 4 total sections: Rules of the Road (90% to pass) Deck
General (70% to pass) Nav General (70% to pass) and Chart Navigation
(70% to pass) Each section has a different number of questions about 50 for the first and I think about 35 for each of the others except the Chart Nav which is 10 questions about half or more are actually plot questions and bet one is a set/ drift in reverse of what you would normally do.
You also have to pass the physical & eye exams, Complete and pass a USCG approved First Aid and CPR class and be drug free and be on a certified random retest program.
All this would be difficult for someone on their own to get accomplished effectively. A school
will generally have everything set up.
And the School was FUN.... we has old salts, new para- flyer boat owner operators, Husband and wives, Father and sons and a Mom, her son and her boy friend, Mom and a knockout daughter, Commercial deck
hands moving up to skipper
status, and a few guys and women who just wanted some additional training and to see what it was all about.
time is the critical issue for most non commercial
people as most of us never documented our time on the water
ever well. A min of 4 hours a day is needed to count as a day... but working 16 hours is still just a day. You may want to get copies of the CG-7195 form and start pulling your data together as you do it. More info is required if your sea time is on a boat not owned by you.
Good luck, I'm sure you will enjoy the trip to obtaining your license... I have. I'll be doing my 100 Ton next spring when I return from the islands.