Winch Orientation

[HeinSdL]

Here is a technical issue which is not immediately obvious but in my view can lead to much higher loads and wear & tear on the winch internal mechanism, as follows.

From my own research reading manuals I have come to understand that the drive cog that drives the winch drum needs to be positioned on the same side as the side where the line enters the drum. So for example, for the starboard genoa winch, the sheet comes in on the outside and therefore the drive cog should also be on the outside.

This makes sense because it minimises the resultant force on the central bearing considerably. With eg a force of half a ton on the sheet then should the drive cog be positioned on the other side of the winch the resultant force on the central bearing would be about 1 ton. Double the sheet tension in other words. With the cog positioned correctly the resultant force would be much much smaller, in fact the central bearing would not be doing that much work at all.

Is this a known issue to look out for? Reason I ask is that on my boat both genoa winches were 180 deg out of line. So I rotated them discovering also that the fixing holes are not nicely symmetric, meaning filling and drilling a couple of new holes.

In use you'll never know, but I do believe it's worth giving this some thought because that central bearing may otherwise have a very tough life indeed.

[tkeithlu]

That's a nice engineering question. The arm is the center of the winch; the distance to the cog is another arm. Ergo, the second arm is always the same length - think of a socket wrench on top of the winch; the load to crank it is the same wherever you have the wrench located. Ergo, it doesn't make any difference.

You can move on to the next of a thousand or so issues. By the way, does your winch only have one cog? Clean it, grease it (waterproof, probably lithium base), and remount it in the same holes.

[HeinSdL]

I made a picture, it's in the attached pdf, hope it attached OK to this message. Winch when viewed from above. The black line is the force being exerted on the drum by the line, the red circle is the cog driving the drum exerting the red force on the drum. The green force is the resultant force exerted by the central bearing on the drum.

[HeinSdL]

I added a part of the Harken manual to my pdf, now attached again. This is what I mean, it's important to get right. Why I make a point out of it now is that the winches on my boat were installed exactly wrong, and I am assuming this was originally the case, out of the yard, so this is something I would check on my boat. As mentioned, during use you won't know, but the unintended internal forces on the winch will be huge.