As much as I appreciate CR experience and competence, I actually think his guess (he did say "I wonder...", in fact) is not correct in this case. To my knowledge, MAN always measured engine power according to DIN standard, which is at the flywheel but with all engine accessories installed (and within certain temperature limits for fuel/air/raw cooling water, but that's irrelevant in this context). I never came across official MAN tables or drawings reporting 860hp for their D2840LE401 engine, or other different power numbers related to any of their engines aside from the DIN ones of their spec sheets that I previously attached, for that matter. But if you are aware of something like that, I'd be curious to see it. BTW, even if usually each engine model is often mated to a particular gearbox model, boatbuilders ultimately chose whatever they prefer, as long as it fits the flywheel housing size - i.e. SAE 1, in most MANs.