I was afraid someone would ask that..
If the rudder works fine with whatever arrangement you already have, I wouldn’t change anything. I think people have been happy with the stock pull arrangement.
But.. I think what I have works very well but has a potential reliability risk. Pulling from where I have the pulley results in the pull being on the order of 50% more effective for holding the rudder down than the stock location and then I have a 2:1 leverage on top of that.
If you look at the attached diagram, the most effective way to pull the rudder is if the pull vector is lined up with the rotation direction. The way I have it, the pull vector is only about 15 or so degrees off from the direction of the rotation but for the "stock" hole location (the unused hole to the lower right in the picture), the pull vector is not at all lined up with the rotation direction - I measured it to be about 65 degrees off. There is also a moment arm involved and where I have the pulley, it’s a shorter moment arm (5 inches - worse) and the stock location has a longer moment arm (7.5 inches - better). Very nerdy of me to calculate this.. but a figure of merit of the pull effectiveness is Cos (angle)* moment arm.
Ill give the details if someone wants, but this ratio ends up being 1.51 i.e., where I pull from is 50% more effective for pulling the rudder down. As I said, add in the 2:1 leverage on top of this and what I have does a really good job of holding down the rudder.
The risk is that you are drilling a hole sort of close to where these aftermarket rudders had a breakage problem in the past. In the US, a lot of people buy an aftermarket rudder from Idasailer (now the company is called rudder craft) and at one time, these rudders would break just above where I have the new hole drilled. This company came out with a newer version which corrected the breakage problem and this is what I have. This rudder is now going on its fifth season exactly like in the picture with no problem. I cant say I wont have a problem from drilling this hole... but I have grounded this rudder at least a few times, left it down when I pulled the boat up the ramp a few times, had it stuck on the ground at that shallow mooring (including some side force) and I’ve done a lot of sailing with this boat. But when I sail, I have a fairly light touch on the tiller and the rudder is always held tightly down. I havent changed anything on this setup for many years.
If the rudder works fine with whatever arrangement you already have, I wouldn’t change anything. I think people have been happy with the stock pull arrangement.
But.. I think what I have works very well but has a potential reliability risk. Pulling from where I have the pulley results in the pull being on the order of 50% more effective for holding the rudder down than the stock location and then I have a 2:1 leverage on top of that.
If you look at the attached diagram, the most effective way to pull the rudder is if the pull vector is lined up with the rotation direction. The way I have it, the pull vector is only about 15 or so degrees off from the direction of the rotation but for the "stock" hole location (the unused hole to the lower right in the picture), the pull vector is not at all lined up with the rotation direction - I measured it to be about 65 degrees off. There is also a moment arm involved and where I have the pulley, it’s a shorter moment arm (5 inches - worse) and the stock location has a longer moment arm (7.5 inches - better). Very nerdy of me to calculate this.. but a figure of merit of the pull effectiveness is Cos (angle)* moment arm.
Ill give the details if someone wants, but this ratio ends up being 1.51 i.e., where I pull from is 50% more effective for pulling the rudder down. As I said, add in the 2:1 leverage on top of this and what I have does a really good job of holding down the rudder.
The risk is that you are drilling a hole sort of close to where these aftermarket rudders had a breakage problem in the past. In the US, a lot of people buy an aftermarket rudder from Idasailer (now the company is called rudder craft) and at one time, these rudders would break just above where I have the new hole drilled. This company came out with a newer version which corrected the breakage problem and this is what I have. This rudder is now going on its fifth season exactly like in the picture with no problem. I cant say I wont have a problem from drilling this hole... but I have grounded this rudder at least a few times, left it down when I pulled the boat up the ramp a few times, had it stuck on the ground at that shallow mooring (including some side force) and I’ve done a lot of sailing with this boat. But when I sail, I have a fairly light touch on the tiller and the rudder is always held tightly down. I havent changed anything on this setup for many years.
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