Running Backstay tang

[Evan]

Hi,

I have a masthead cutter rig on my 40' catamaran, and it came with fixed intermediate backstays to oppose the staysail forestay. I don't like these because the main will chafe on them sooner when let out, but also because you have to have a tremendous amount of load on them to get only moderate inner forestay tension.

I want to replace the fixed intermediate backstays with a high modulus rope running backstay.

The existing rigging is 5/16" wire, and the tang looks like this: (I think it's an old Navtec model).
http://bp2.blogger.com/_nqJ71MFvkNI/R-SbxbN7qUI/AAAAAAAAAUA/QdNjM-aNkTs/s320/CIMG1024.JPG

he mast is up right now, and I don't want to take it down if at all possible. Logistical hassles due to the boat's location.

I am leaning toward just a pivoting strap tang with a single bolt. Should I:

(1) just thru bolt the new tang a foot or so above old tang?

(How do I do this safely without drilling thru the halyard holding me up?)

(2) drill thru the existing tang with my thru bolt

(3) custom make a tang from a block of solid aluminum that fits in the existing tang slot (good luck getting those old s.s. machine screws out)?

(4) anything else I'm forgetting?

(5) maybe try to get a stemball fitting that will fit in this type of tang with an eye for HM rope.

I'm grateful for all advice; good or bad.

Evan

[Evan]

What I ended up doing was removing the fitting from the mast with an air driven impact driver. Removed the old wire easily. Drilled a hole through the top part of the visible casting (opposite where the wire enters). Rounded the entry and exit for the hole with a dremel and a cone shaped bit. Then lashed the Spectra backstay eye to the fitting with lots of turns of 1/8" Spectra. Very flexible and as the loads won't be too great (just the runner for a small staysail) I think it will work quite nicely.