Quote:
Originally Posted by gap
...
Max speed points for both diesel and electric propulsion are substantially aligned on the same straight line, wereas min speed values can be interpolated by two lines whose gradients are similar to the ones seen in the previous graph, with electric propulsion having a lesser slope than diesel propulsion (0.0262-0.0280 vs. 0.0357-0.0366). This makes me to think that the max speeds reported for each speed order are sort of theoretical values. What do you think guys?  |
I believe that both sources are more than credible. A linear speed-RPM dependency is normal for propellers in water (as opposed to air) for an example look at
this chart and we here are talkin about very low RPMs at which this linearity would be even more pronounced. Let linearity here not confuse you: water, as opposed to air, is almost incompressible at these speeds that is why propellers are not loosing much of their effectiveness. It would be way more interesting to see speed-P.S. charts where there would be a lot more 'curviness'. As in terms of max-speed: I would go with British repots since German ones most probably give a brand-new boat specs as opposed to the British 'old-boat' ones and while at the moment we don't have a possibility to 'degrade' engines' performance we better set it slightly lower straight from the start.