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Propeller rotation - important? - Yes, it is.
the trust bearing is wrong.
anders.lassenNEJTILSPAM (at)adr.dk wrote: Hi, Recently my propeller threw off a blade. I ordered a new propeller from Michigan and today it arrived. BUT - my local dealer made a mistake: He ordered a right-hand propeller - but the old one was a left hand rotation! I just waited for four weeks - and really wouldn't like waiting another four weeks for another to arrive. So here's my question: Is it possible to reverse the direction of the transmission instead so I don't have to change the propeller? The engine is a Yanmar 6LP-STE and the transmission is a Hurth/ZF. And: Should I do it? I mean - Is there any drawbacks in changing rotation? Anders Denmark Hi Anders, I hope it will be not too late for a reply to your question. Rotation is not a your choice, but it is depending from the boat manufacturer designer. You don't specify WHAT kind of transmission you are using, but presuming you own a classic one comprising an Engine, a Marine Transmission, a Propeller Drive Shaft and a Propeller... ...you will have these problems... It is depending from engine rotation (LH or RH), kind of transmission gear (LH or RH, Forward Ratio and Reverse Ratio, Forward Torque and Reverse Torque, Internal Gears design etc.) Some technical details: Usually all engines are "LH" (seen from Flywheel side). Usually Forward is "direct drive" meaning that there are only TWO gears engaged... so Rotation of Propeller Shaft is inverted versus engine rotation ( LHRH=RH) ... so Propeller has to be RH . Reverse is done by THREE Gears... so Engine and Transmission Shaft have same rotation ( LHRHLH=LH ) so a RH Propeller rotates LH and does REVERSE. Where is the matter? You will have NEVER the same ratio Forward and Reverse: Forward has TWO Gears coupled together and transfers a lot of power (direct drive). Reverse has THREE Gears coupled together and the Second One is a small one rated (designed) for a limited Torque and use. So you cannot use "Transmission Reverse" for " Boat Forward". So, if you wish to use a "Reverse Propeller" you have to replace ENGINE with a RH one! Of course there are other options, but these are the most important ones. +++ Otherwise... if you have another kind of transmission, and specifically the one with Forward and Reverse similar to the one used on Outboards ( Three Bevel Gears Style with Cog Clutches ) there are no matters... Forward and Reverse have same Ratio, same Torque, same Cog Clutch.... so RH or LH are optional choices and are not involving any other part or performance... +++ The answer is exclusively depending from the parts involved in. I hope this could help you. Regards, WinXP PS.- I don't know who-where is your Supplier... but any decent Supplier has "a lot" of used Propellers available for speed tests or power test or saved or... so he "has to have" a decent one for emergency purpose... Important is it has same HUB and same Rotation... Pitch, Outer Dia and number of Blades is relative... By the way, it is a good idea to have a "replaceable" propeller on board... |
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