rlgeorg,
How many hours on those MAN's? Check with the folks at MAN down in Pompano (website -
http://www.man-mec.com/home.htm) and see if they can give you service intervals, this way you know what you are getting into. Also check to see if you give them the engine serial numbers they can get any kind of history on them. Somebody (delaer or licensed technicians)probably worked on those engines and has a history. I ran a 61 Sunseeker with 1,050-hp MANs and they are great engines, but need to be looked after. If memory serves me correctly, there is a major servicing at 1,000 hours.
Also, newer MAn's have common rail engines, cleaner, quieter and better efficiency. The Man's inthe Viking will undoubtedly be the mechanical type, maybe a little smoke at startup, bit more vibration. Oh yeah, on the 1,050-hp, at idle only half the cylinders are firing (built to do that) but gave a fair amount of vibration. Check to see if the 1200 does that.
Hope that helps.
Capt Tom