crazy prop shaft angle

Nothing particularly unusual. Guess at 15 degrees which is maximum for most engines. Clearly wanted to install the engine as far back as possible and still swing a large prop.
 
I wouldn't say it's crazy, but it looks steeper than most. Certainly more than the 15 degrees some have guessed at. If the crankshaft is parallel to the prop shaft, I wouldn't get away with it with my engine (which, FWIW, sits at 10 degrees compared to a permitted max of 15.)
 
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macd said:
I wouldn't say it's crazy, but it looks steeper than most. Certainly more than the 15 degrees some have guessed at. If the crankshaft is parallel to the prop shaft, I wouldn't get away with it with my engine (which, FWIW, sits at 10 degrees compared to a permitted max of 15.)
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Could be a Farymann engine with Hydraulic drive such that the engine can sit anywhere and installed horizontal.
 
the angle looks a bit steep the prop wash only hits the last 3rd of the rudder so manovering would be limited , seems inefficent... there is also a plank seat at the stern so the crew can keep; the stern down while under power
 
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macd said:
Could be several other things as well, none of which I discounted. But isn't it the propshaft angle we're discussing rather than how it's spun?
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I think jcorstorphine infers that the use of a hydraulic drive allows the shaft to be installed at an angle more divergent from the axis of the propshaft than would apply in more traditional arrangements, thereby allowing the engine to be sited further aft.
 
Spirit of Glenans said:
I think jcorstorphine infers that the use of a hydraulic drive allows the shaft to be installed at an angle more divergent from the axis of the propshaft than would apply in more traditional arrangements, thereby allowing the engine to be sited further aft.
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He may well have inferred that. He more likely implied it ;)
But I'm not sure either necessarily explains the somewhat steep shaft angle. Surely one benefit of hydraulic drive, apart from giving flexibility in engine location, is that it allows similar flexibility in placing and orientating the shaft how you want. My take is that the OP isn't asking by what means the shaft can be engineered to work at this somewhat steep angle. He's asking why.

I'll certainly grant you that his somewhat minimal opening post allows other interpretations.
 
macd said:
He may well have inferred that. He more likely implied it ;)
But I'm not sure either necessarily explains the somewhat steep shaft angle. Surely one benefit of hydraulic drive, apart from giving flexibility in engine location, is that it allows similar flexibility in placing and orientating the shaft how you want. My take is that the OP isn't asking by what means the shaft can be engineered to work at this somewhat steep angle. He's asking why.

I'll certainly grant you that his somewhat minimal opening post allows other interpretations.
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I stand corrected:)
 
macd said:
Could be several other things as well, none of which I discounted. But isn't it the propshaft angle we're discussing rather than how it's spun?
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My usual thread drift, I suggested the hydraulic drive as a means of getting the steep angle as macd mentioned engines not being happy at what looked to me nearer 20 degrees.

However, cant look at pic any more as boat has been sold / withdrawn :)
 
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