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Paddlewheels versus Propellers
"a" wrote Even more aviation: you could not maintain altitude: couldn't get up on to planning speed. But 5 knots? My 25 foot swing keel O'Day (think of the keel as a vertical wing) could do that in a reasonable breeze and it was NOT a fast boat. s Not surprising, to me. Every boat has a "hull speed" than can be calculated, relating mainly to length, that applies in a strictly displacement mode. The longer, the faster, generally. The O'Day 25 (used to have one) had a hull speed of about 6 1/4 knots. To go faster you would have to apply enough HP (LOTS more HP) to get up on plane, and I suspect the one engine in the power boat did not have enough power to get it over the hump. Also consider that a considerable amount of one engine's HP would be consumed by rudder drag, since the rudder would have to be nearly 45 degrees to keep the boat going straight.. Also, the 5 knots mentioned is probably not terribly accurate, since the accuracy of a power boat's "speedometer" is not very good at low speeds. It hurts my head to think about what parts of the two engines were common, and which were different. Not that bad, I think. Camshaft, crankshaft, oil pump, water pump, harmonic ballancer, distributor, alternator. _ Jim in NC |
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