Just replaced a very chafed (pictured) Wishbone Choker line – the 7’9" line that connects through the block at the forward end of the wishbone boom. The chafing occurred between the block at the forward end of the boom through to about 1 foot below the cheek block on the mast.
Last replaced about 5-7 years ago. I suspect this is just normal wear and tear, as the line touches the boom for about 3 to 6 inches between the forward block and the cheek block (pictured). This is normal, correct?
Any suggestions to reduce or eliminate the chafing? I noticed the problem at the end of a weekend regatta with 18-22 knots steady and gusts 25 -35 kts (much more than we usually experience on the Hudson River), so we probably gave the line a real workout.
Thanks
Tony Martin
Sheba (Nonsuch 30C 212)
Nyack Boat Club
Nyack, NY 10960
Tony,
Is it possible that the mast was rotated to an out of position place?
It doesn’t seem right that the turning block is out of alignment to the choker line.
Brian
Boat-less in New England
From experience on the same chafe, I suggest that you examine very closely the roughness on the upper leading edge of the choker turning block including the mounting shim over which the choker line passes before entering the sheave in the turning block. On a new Gauhauer turning block with a stainless steel guide, there was just enough roughness to wear through the cover on my 1/2” choker line after several years of use. Using very fine files and wet/dry sandpaper, I rounded the edge to reduce chafe but you’ll never completely eliminate it. I’m eye splicing a new double braid 1/2 “ choker line this winter.
Ken/Tony
What about the friction of the line around the mast, would not that cause a sawing effect to the mast integrity?
Brian
Boat-less in New England
I don’t think so. The line will give out long before and is prone to chafe at the forward top edge of the turning block cheek and mounting shim. Some chafe will occur against the mast surface but I think most at the turning block.
Ken
Crazy as it sounds, the turning block is positioned such that, in general, the line does chafe as it moves. One of those “less than perfect” bits of design. On my (just sold … boo hoo) NS 22, I had the same problem.
It has nothing to do with the mast rotating (which I’ve never known to happen).
It’s hard to tell from the perspective of the picture. It does make it appear like the turning block is further back around the mast than I would’ve expected, but like I just said, it’s hard to tell. And, as you can see on the attached picture, the block and eyestrap actually are pretty far back.
My turning block on my previous N26C failed before the brand new line the previous owner had recently installed. That’s why I’d taken this picture.
The interesting thing, indicated by the red arrow, is that someone had welded a half-round bar to the base of the turning block, angled just right to give a smooth, chafe-free passage. Unfortunately, the sheave on this original Nicro Fico was completely gone on the opposite side that you can’t see in this pic. No one sells a cheek block with the matching trapezoidal pattern any more, either.
After I paid a rigger to re-drill the hole pattern in a larger, new block, I heard that you might be able to talk to the people at Garhauer Marine (www.GarhauerMarine.com, +1 909-985-9993, info@garhauermarine.com, open 7:00 am - 3:30 pm Pacific time M-F), and get one of their blocks made with a base plate that matches the pattern. Since I didn’t find out in time, I didn’t try them, but I’ll be they’d do that. And I wouldn’t be surprised if they could be talked into welding on a half-round piece, either.
Alternatively, Mike Quill may have remaining stocks of a block he made at one time (mqyr.com).
Another alternative solution is what I found on my current N26U, where the cheek block is replaced with a hanging turning block, as shown in this picture. There are some aspects of this I want to fine tune, but I generally like the idea.
The hanging block is kept away from the mast by a vertical line tied off on the mast eye for the boom hangers (red arrow), a horizontal line from where the cheekblock would be (blue arrow), and the pull of the choker line (yellow arrow).
It needs some tweaking to be ideal. I’d like to slightly shorten both the vertical and horizontal hanging lines for the block. Currently, they let the block go too far forward and down. Too far forward prevents the boom from being pulled back as close to the mast as I’d like. Too far down twists the block at the front of the boom. That block really should be lashed to boom front, anyway – the current arrangement, with two shackles to an eye rigged to a cover plate over a worn out attachment hole, deserves a caption of its own. Like, “Rube Goldberg goes to sea.”
Nevertheless, once it’s tweaked, I think it’ll go from being a very handy hack to being a really nice alternative.
Looks to me when the mast was built the track was placed on the wrong side because as Bob mentioned the blocks are in the wrong place.
One possible solution is to use Dyneema for that section of line. Have one made up with loops in each end and use a soft shackle at the terminal end. I’d file the sides of the blocks smooth as possible. Check it every year.
My line just got replaced after 20 years and there was no chafe, so if you are getting chafe it should be mitigated.
