I worked at a boatyard which specialized in diesel
work but we did the full range of services. I was an electrician. My opinion (and that's all it is) is that you need to get experience with a wide range of motors and installations to be a "good enough" mechanic
to work on others diesels. To do that you probably need at least a couple of years, or more, working with more experienced mechanics as a trainee.
You would certainly be somewhat of a help with those in need in remote
locations but you would quickly find that you will be stumped by a variety of issues that are brand specific and installation
specific, not to mention the huge variety of gremlins that can cause problems on boats.
A diesel school
will cover the basics of basic diesel motors but usually will not address the specifics of marinized diesels. They aren't really that much different in many ways but enough to be an issue. You will also need a big set of tools. Offshore
sailboaters often already know a lot about their engines, and many of them will certainly know more than you do when you show up on their boats.
You won't have the opportunity to rebuilt motors out there. You'd need a shop with a lot of equipment
Having said all that, it would be invaluable for you to learn all that for your own purposes and to help with the occasional problem on other boats. I've seen many guys out there who tried to make a living off of maintenance
and repair of variety boat bits (water makers, electrical
, diesels) but it is very hard to make much money
and you get lots of opportunities to irritate (and more) those who hire you and then find out you don't really have much experience. Real damage can be done with good intentions. E.g. a non-boat diesel training program will not teach you how to align a motor
to a prop shaft, or how to replace/fix all the hundred different varieties of raw water
pumps/impellers. And you need the right tools for all that.
And, having said all that, some few are natural born mechanics and they can get through it all. IME very few. It is easy enough to get bad work from experienced mechanics.
If you do want to go to school for this, you'd be best to go for 2-4 semesters. One semester would get you to where you could do some very basic troubleshooting and oil
changes. There are also some good marine
tech schools that have good diesel training programs. You should check some of those out. Unfortunately, they may not be close to where you live so that would be a definite issue. In all honesty you're looking at 1-3 years to get where you want to go.
I wanted to learn marine electrical
so I basically apprenticed (at 50 y/o) at a boatyard and it took me a couple of years before I felt more comfortable on my own in some situations. And I am still no where as good as the guys who have been doing it for 10-20 years or more. But it is possible. I had hoped that after 5 years full time working with one of the best electricians I have run into, plus two years of part time classes
at a marine tech school, plus ABYC certification
, that I would be able to find enough paying work to make some real money
. I found out that I got the occasional big job. You have to be in one spot and build up a reputation to get regular jobs and it has to be where lots of boats come through.
And word gets out very quick if you are seen as not knowing very much, or worse, screw up a couple of boats. You could get more work with power boats in general. Sailboaters are cheap(er) and more self reliant and will only pay for help for very hard problems. Or they'll get "free" help from guys like me.
So that's one person's brain dump. Some others might disagree. I wish you luck with it as all things are possible.