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post #39 of Old 08-07-2013
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Re: Yanmar hard starting question

Yea, I didn't appreciate his blatant direct attack on me either... when he obviously missed the whole point on light vs heavy duty designs and didn't understand the marine environment and what in essence is an Archimedes' screw trying to "screw", albeit inefficiently, through a fluid medium when at speed (as in a planing hull) combined with the primary forces in effect which are a combination of all three of Newton's laws of motion depending on several factors. He somehow mistakenly thought there was a 1:1 relationship on the prop's engagement to its medium as there is in a purely mechanical link to a load as in a direct connected machine or rolling stocks traction to its road. A prop does not have a true 1:1 engagement. The actions of the water on the hull almost always absorbed by the the prop's slip and do not impart enough delta to the shaft/torque to activate an internal governor. But he missed all that.

But hey we're all idiots in his mind.

Most of the marine installations I've seen were governed solely by the prop. In diesels where the engine included internal governing as part of its injector pump design... if properly propped... the prop's upper end of governing and the engine's internal will meet only near 100% torque and the max rpm the prop will allow at that torque input. If over propped it will not even get near the governor's max rpm setting. If under propped it will and prevent over revving. But he missed that too.

I also tried to explain that insulting every one did him no merits... but its doubtful he'll listen.


1980 Seafarer Swiftsure 30
1978 Bayliner Buccaneer 270 (now sold and being restored in FL)
1962 SeaMac 14' Plywood Runabout, mahogany decked, with 1959 Evinrude 35 Big Twin (owned since age 17, I'm now 60)

Last edited by dem45133; 08-07-2013 at 10:25 AM.
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