Be very very careful about using mechanics, engineers or boat maintenance "professionals" even if they are recommended.
I recently bought a yacht with a Beta Marine engine, asked the local Beta agent to undertake a service and was ripped off to the tune of $600. They came highly recommended. I cant even list all the errors and mistakes they have made.
When you employ a professional, they will not (generally) give the job as much care and attention as you would yourself.
Nigel Calder has a very good book on electrical and mechanical systems on board.
I strongly recommend investing in, and reading this book carefully. He describes installing a fridge, fitting the heads and just about anything else you might well come across.
If you yourself are not the most practical person in the world, you will still learn a lot and understand what is involved in completing these jobs. You will be less likely to be ripped off.
It may also get you out of trouble when you have problems and you are in a quiet anchorage on your own.
Be as self sufficient as possible and understand your boat and systems.
