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Old 06-15-2014, 03:38 PM   #2
Nomad Willy
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City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
I'm almost positive it's engine rpm so your stbd engine will be under more load. And more thrust on that side. If you don't have counter rotating props you maybe better off switching gears on one side to the other to counter the tendency for the boat to turn to one side depending on prop rotation.

If you do have CRP then the engines will be in out of sync when the rpm causes the harmonic vibration to make the hull drum. Rather like a twin engine aircraft slightly out of sync. The closer one is to sync the lower the frequency of the drumming harmonic vibration. Sync them w tech or w ear. No drumming when in sync. Engines must be able to maintain rpm well.

Never heard of it but theory would say you may have prop harmonics when the engines are in sync. And if you do I would think the only escape from harmonic vibration would be gears w the same ratio.
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