Yanmar-Kanzaki clutch slipping

[double u]

I dont understand this “no sailing in reverse“ rule. The torque on the cone should be in the same direction as motoring, no?.

[a64pilot]

Originally Posted by double u

I dont understand this “no sailing in reverse“ rule. The torque on the cone should be in the same direction as motoring, no?.

I’m not sure for cones, but my clutches are designed in such a way that the more torque applied by the engine, the more compressed the clutches are, that way they don’t slip and self compensate for wear, any force feeding backwards meaning coming from the output shaft would result in loosening the compression on the clutches and may make them slip.

I’d imagine that the cone type of transmissions would be similar.
What’s the advantage of cones anyway? Why replace clutch packs with cones, clutch packs have been around forever and seemed to be pretty much bullet proof?

I just put my engine in neutral let it idle for awhile and shut it down, my autoprop will feather or saying it another way, without their being any rotation, the blades will position themselves into the water flow for least drag.
They have to, they are simply blades on a bearing, they aren’t geared together or to anything, centripetal force drives them to flat pitch and water flow drives them to feather, underway the forces balance each other, remove the centripetal force but still have waterflow, they feather, they have to.

[S/V Adeline]

Originally Posted by AnglaisInHull

RANT
I can't believe how hard it is to get information about some marine parts. I tried for two years to find out where this transmission came from and get any info about it. And then the Yanmar technical bulletin starts with a complaint about the customers: "We keep getting questions about ..." Well, if you actually put this kind of information on your website maybe people would stop asking the same question all the time. Or if you had a dealer network that knew something about the parts and was willing to talk to people.

And don't get me on about Nanni engines.
/rant

I agree with your rant. Just purchased a new Twin Disc cone transmission. One manual, direct from manufacturer's website states the tranny must be in neutral while under sail. Another manual, also direct from manufacturer's website (different page, but same transmission id) states reverse can be used to prevent shaft rotation under sail.
Emailed manufacturer, noted discrepancy, their reply: :crickets:

[dfelsent]

Cones have been around forever too.
I drop to reverse to feather/fold then neutral.

[kenbo]

Originally Posted by double u

I dont understand this “no sailing in reverse“ rule. The torque on the cone should be in the same direction as motoring, no?.

The difference is when you're motoring both the input and output shafts are rotating at the same speed.

When one or the other shaft stops rotating you are asking the cone clutch to do something it's not designed to do, act as a brake. Admittedly the damage done while sailing in reverse takes time to be fully realized, the damage I can be quite instantaneous if you were to wrap a line around the prop while motoring. You'd be fortunate to only waste the cone clutch.