Shrouds

Sylvester · 09 Mar 2018, 08:52

Anyone seen this before? More to the point how do I replace as one side is greyed, looks to be a proctor alpha on my newly acquired 3120 tigress. The other side has been replaced by joining. Any advise would be appreciated. Thankyou.

Sylvester · 09 Mar 2018, 08:58

Don't really want to replicate this

gbr1918 · 09 Mar 2018, 10:24

Messy! Yup, in about 1970-something I crewed on a quarter-tonner that had shrouds that worked like that: there were soft eyes in the shrouds and that thing that looks like a giant rivet in your pic goes through the eyes. The giant rivet thingy must come out: your pic isn't very clear but it looks as if it has internal splines. I suspect it is in two halves threaded together and you can unscrew it using either allan keys or torx drivers. But I may be totally wrong about all that, of course!
Dave

PS the quarter tonner's mast was made by Kemp (dunno what became of them!). I remember it had another weird feature: on either side of the mast there was a textured strip (ran all the way from the gooseneck to the top) which was supposed to be a turbulence-generator which (the skipper said confidently) improved laminar flow across the mainsail. I've never seen that anywhere else, either!

NTOACertification · 10 Mar 2018, 09:43

This method of attaching shrouds to the mast was pioneered by Needlespar in the 70's.
They used a solid aluminium for the pin, which was ,with some work, removable and the shrouds could be replaced and a new pin ( supplied by Needlespar) could be fitted.

Proctors followed suit but used a hollow stainless steel pin, which was difficult if not impossible to remove.
It would not be wise to remove the pin if you cannot replace it. The damage shown on the second photo is not clear, but the shroud slicing down the mast was very unusual unless a rigging failure has put an different stress on the shroud.

You could look at fitting T Terminals but this may result in the shroud attachment point moving too far up or down relative to the jib halyard point.
Also Old fashioned tangs could be fitted but this is pretty messy.

If the shrouds are fitted significantly more than 100mm above the Jib halyard, the mast have more pre-bend (and will be more flexible in the gusts). If the shroud point moves down the amount of pre-bend will decrease.

Hope this helps

Kevan
NTOA Hon Certification

Sylvester · 12 Mar 2018, 11:32

Thankyou for your replies. I have decided to replace and swage the ends of the pin with a jig made from an old cycle Axel and bearing cones. This is mainly as I don't trust my self with a hammer near the mast. Thanks again. PS. Could you be the Kevan that made my lovely sails?

icecreamman · 01 Apr 2018, 02:40

If it is any use my father had a Needles par back in the day on his Whisper and being the engineer he is did not like the aluminium pin that was driven through the mast to hold the shrouds. He replaced that with a stainless steel bolt to which he attached plates not unlike a bit of Mecanno and from these hung the shrouds.

Sylvester · 02 Apr 2018, 12:04

Thanks icecreamman! That's kinda what I'm going to do. I have an old gold procter solo mast with the same diameter pin but external tangs, going to bolt them on. Other 12 has same mast but with the same tangs, doing it this way will mean the shrouds will be interchangeable.