No it should not, however you'd be exerting continual and varying strain on the trannyo couldn't resist), unlike when leaving a manual transmission car in gear when you park.
That's basically what I figured, but I wouldn't think that the strain against a still prop at ~8 MPH could possibly be more than the strain it's under when pushing 22,000 lbs @ 23 kts.
Again, not an engineer. It might be fine. But I'd worry that problems could arise from the strain being variable and in an unlubricated tranny.
Long post to clarify one thing, it doesn't save fuel to run on one. I had a 370, the older brother to the 406. Running on one engine did not save fuel in any way at all.
In and around Long Island where so many do not know the rules of the 'road,' combined with little room for error on weekends due to everyone out on the water, I'd not risk losing the control of having two engines to save money; it becomes somewhat of a safety issue with the large number of boaters that don't consider ANY vessel being the 'least maneuverable' and thereby having the right of way.
Hi, Unless it is a fully mechanical gearbox the answer is yes, if it were a fully mechanical gearbox it would eventually turn the crankshaft as well so that would do you no good. Having traveled from the Seychelles to Lumut, Malaysia and then most of the way from Cairns to Seattle plus several Atlantic Crossings on large yachts running on one engine I can honestly say I have a lot of miles running on one engine as against the two fitted. I can say with some certainty that running on one works to increase the range and save fuel as long as it is calm and you do not try to run the one engine at full nana. Most bigger diesel engines with mechanical injection won't turn at full output RPM when running one alone, it will simply overload the engine and waste more fuel than you will ever save. Going a bit slower makes fishing a lot more productive but has to be abandoned as soon as the swell picks up deep sea as once you start pitching the speed drops off to a crawl (4 or 5 kts) quite easily.