Sunday, December 6, 2015

Sta-Lok Side Stay Repair

This fall when I was putting the boat away I checked all the stays to see if there was any rig damage that needed to be repaired.

The fore stay and back stays checked out fine but my lower side stays both has some strands of the cable that were visibly broken.  I am sure these are the original stays so they have seen a lot of use over the years.

The S2 6.9 original equipment has 1x19 5/32 stainless steel cable with 5/16 thread for all stays and shrouds. The threaded end of the stays all have a right hand thread to tighten.

Broken Strands
I first looked into having totally new stays built with swage fitting on each end to replace the old ones. These swage fittings are compressed onto the cables with a heavy duty industrial press.

I even thought about replacing the stays with new rope stay material called Dyneema. After all, the sailing ships of old all used rope for their stays to support the mast.

The Dyneema rope is just as strong as the stainless steel wire material and much lighter.  You can read more about it at this Sailfeed link if your are interested.
The total replacement of the shrouds would be more expensive so I chose to just replace the ends. The 5/32 1x19 316 stainless steel cable costs about $1.00 per foot. So it would cost about $32 for the two lower side stays.  The T-Ball swage fittings that go into the mast cost about $25 a piece and the threaded swage ends go for about $17.  I would then have to find someone to compress these onto the cable.

The rest of the existing cable seemed to be in good condition so I opted to just replace the threaded end with a mechanical fitting.

There are several companies that make mechanical fittings for wire cable. Sta-Lok, Norseman and Hi Mod are the three companies that I know of.  I did a quick Internet search and found a 5/32 Sta-Lok long barrel threaded fitting on the P2 Marine site for about $44.  Make sure to get the long barrel terminal, it will provide about the right length compared to the old fitting.

These mechanical fittings are very reliable and are actually stronger than the cable you are attaching them to.  The fittings can be reused also but a new center cone and forming cone will need to be purchased.

The first thing you have to do is cut off the old terminal to prepare the end for the new one.  I used my Dremel tool with a cutting blade on the end to zip it off quickly. Make sure to make a nice square cut so all the strands of the cable are the same length. Use a file to clean up any burs on the cable.

Cutting off the old fitting
There is a real good video on YouTube that details the whole process of replacing a fitting of this type. Check it out for the step by step instructions.

The video also has many good tips like sealing up the connection with silicone to prevent water intrusion into the fitting.
Sta-Lok pieces

The Sta-Lok fittings have just 4 parts. The main threaded barrel(at bottom), the top nut(top right), the forming cone(middle) and the spreading cone(top left).

First place the top nut onto the cable. Next spread the cables outer strands by giving the cable a counter clockwise twist. Slip the spreading cone insert, skinny side first, onto the 6 inner strands of the cable.

The forming cone fits in the bottom of the main threaded barrel. This is what will form the strands into a nice round shape as the nut forces the strands around the center cone.
Strands before pre forming strands
I followed the procedure used in the video and first tightened the nut down to preform the strands around the inner cone.  I then unscrewed it to see if the strands all formed properly. I was lucky that it worked fine.

I then filled the fitting with silicone and tightened down the nut again.  I used lock tight on the threads as suggested in the video and tightened down the fitting until snug.

That is it! I should be good for many more season to come.


Finished connection