Spinlock rope clutches as-built fit. Rope Size?

[Sea Simon]

Help please,

What size of ropes can be used in the Spinlock rope clutches as fitted by the yard to the cabin top on a BRe?
Min/Max please.

I need a new halyard.
I have the length; I will allow another 3m this time for trimming back. Shortsightedly, I only went 1m over length last time. All used (3 seasons!), and needs trimming again as the outer sleeve has worn right through.

I don't have the range of the sizes that these clutches can deal with. I think there is a rope size sticker on the clutch, but foolishly did not write it down (I can now blame my long-Covid!). I'm thinking smaller D, but at high strength might be better?
Boat now mid river in a nasty wind over tide rip. Don't fancy a trip out to look today; looking quite iffy at the moment.

Current rope has not lasted the conditions at mast top well at all. Have been trimming twice yearly. Clearly ought to have end-for-ended this winter. Drat.
Clutch area is fine, v little wear. I'm sure the way I've been attaching halyard to the sail is very hard on the rope.

Small sheave, angry sharp metal headboard to sail (I've attempted to fair this a little with a Dremel).

Any suggestions for improvement?
How do others attach their halyards? I've been doing it dinghy style, with a "bobble on the bight".
Do I need a clip/shackle? Is their sufficient length on the hoist?

Thanks.

[Sea Simon]

Visited the boat. To partly answer my own question...

The clutches are marked 6-8 mm.

I have 7mm braided dyneema fitted at the moment, but this has not lasted; the braided polyester cover is completely shot, core OK.
Maybe some UV issues?
Now have a long length of similar in 6mm D.
Seems I will just have to trim/end for end more regularly?

I will also start using a shackle halyard>headboard. Is this what others already do?

Note. I don't use the winch on my main halyard.
I find a ClamCleat power grip adequate.

[TimLM]

Hi Simon, I know my boat has a different rig but all the boats I've sailed always had metal to metal on the main halyard. I also use dyneema cored halyards with polyester cover 6mm and 8mm on the 2 fore sails which give enough tension with simple clutch and jammer just leaning back on a byte without a winch. I use a Wychard snap clips to connect both throat and peak halyards If you have the space they make rigging so much easier.
The "Bomb Proof" halyard is the same dyneema with a "technora" case, this survives even ceramic clutches but does increase the wear to all it runs through.
I was very sad to hear you've suffered long covid I do hope you recover, Tim

[Sea Simon]

Hi Tim, good to hear from you. Thanks for info.

Metal sheaves? Agreed. My thought being a smaller D rope may better suit the sheave/reduced turning radius? Can't see that a bigger sheave would be possible, nor desireable at mast tip.

Ropes. May follow your advice re Tecnora next time, but in my impatience to get sailing have already ordered more poly/dyneema...more meaning longer, with more spare tail! I'll try to chop/end for end more frequently.
Interesting that my similar (but "classic" poly/D, from same manufacturers) jib halyard is aok.
Black v Buff colour maybe?

Alloy head board easily faired up a little; it was like a knife edge.

Attachment. I've gone for a Wichard D shackle with bar. But, I'm now concerned that splicing the halyard to the shackle may mean the halyard will not fit the sheave...whole assembly will be quite long. Perhaps just knot it?
I may yet need a snap shackle; at least the D-Bar was a "free" shed find.
How have you attached halyard to snap shackle?

Covid. Thanks Tim.
We've been very lucky. I caught it at work, I'm sure (in NW England-plenty there, and a globally sourced workforce too!) But due to fortuitous self-isolation before positive test, I managed to not pass on to family or friends/local community (no others hereabouts have been infected; at all).
Nasty business. I was not hospitalised, but I never expected the long version at all really, never mind for it to be so debilitating. No Dinghy racing at all last year, and still now barely able to walk up the slip, never mind pull a dinghy up too. Feels like I've aged 15 years.  ?
I think the dinghy will probably be sold next spring?