Jroyle - I agree that the factory provides abundant documentation on installed systems, Garmin, Volvo (I have the Volvo not Yanmar engine), A/C, Fusion radio, thrusters, etc etc. What is lacking is documentation on the boat itself - plumbing, wiring, venting, etc. You're quite right, the factory does a credible job in answering inquiries, but my point, and I think that of some of the others, is we would like to be familiar with what's under the deck BEFORE it goes south. There isn't always a professional mechanic available when you need one. I have been playing with boats - 12'-45' (mostly sail) for 65 years and I am pretty good at figuring stuff out. That said, I am not from a mechanical/electrical background: I am a writer. But Wouldn't it be easier, nicer, more efficient to have a systems manual ON THE BOAT in addition to the "how to operate" manuals on the electronic, a/c etc. I have the PDF one for my 21EC and keep it on the boat referring to it from time to time. (My kids and grandkids tell me instructions are for people with no imagination. Oh well! Guess that would be me!) Sorry you disagree but there you are! Merry Christmas