Same question that seems to repeat itself with no clear answer. The NS 30C specs show the “Wishbone Choker” length should be “7 ft 9 inches”. The NS 30U specs show the length of the same line as “9 ft, 6 inches”. I have seen postings that suggest using the “7 ft 9 inches” length for a NS 30C and NS30U.
The length of Wishbone choker is critical in terms of being able to apply enough tension on it to move the wishbone to the best position when sailing. What is the group’s recommendation for the Wishbone Choker line on a Nonsuch 30U, A) 7 ft 9" inches or B) 9 ft 6 inches?
Other than looking it up in specs as you’ve done and having replaced mine a few times over the decades ( this spring being one of them).
I would think a length long enough ( say the longer of your two listed lengths) such that the block and tackle that rises up & down within the prescribed area of operation along the stbd side of the mast.
When I installed the recent one I snugged it up on the stationary port side ring and then had a crewman tight down till the rubber bumpers touched the mast. Then loosened it up completely to see how high the block / tackle would rise to. Once I saw that the assembly stayed within operational area along the stbd side of the mast I made the final knot to hold in place. Hope this helps.
This does not specify the length of the line, but it should guide you in determining that length. It isn’t the length of the line which is important, it is the geometry of the choker and its relationship to the blocks on the mast and on the boom which are important.
I can’t speak to your specific situation, but I can say that I rigged a new choker line for a friend’s N36 at the 9’ length specified in the N36 manual, and it left the choker block and tackle pretty close to the bottom when pulled all the way in.
It depends very much on how your boat’s rigged, though. The N36 I was working on had a turning block fixed to the mast at the bottom of the floating tackle as the limiting point. Not all are set up that way.
Mike, the choker arrangements on the early 30Cs was different than what was used on the Ultras. I have found the best option was to start with the length of your current choker. If it works stick with that. The original system likely had a 3:1 purchase. If someone changed it to a 4:1 purchase it might have been necessary to change the length of the choker line to allow additional movement of the tackle blocks. Mark
Mike, the line length on the 30U is greater because of the extra purchase of the single block on the chocker line suspended in between two turning blocks.
It adds a few feet. I can show you a sketch made by Earnest from Toronto. As soon as I find the sketch I will send it to you.
