"To say it is preferred is against all accepted criteria regarding diesel cruising speed. I don't agree with smitty447."
If you would really like some good feedback go to boatdiesel(dot)com and ask this same question.
Or you can go to Tony Athens site or call him up and ask his real world experiences with engines of this type at sbmar(dot)com.
Or just go to the sbmar site and read "Tony's tips" for some good background.
Its been 25+ years that I have run similar sized 6 cyl 4stroke diesels with plenty of feedback from similar owners with all good results.
Cruised long Island waters for many years now likely have been out there on the water with you at some point.