I don't think there's any explanation that you're missing.  My boat as it came to me from the GB factory after recycling has 5 shrouds threaded one way, and one shroud threaded the other.  It would be less mentally challenging to rig the boat if they were all threaded the same way, but other than that, I can't see that it makes any practical difference.

Peter Nyberg
Coventry, CT
s/v Silverheels (1988/2016)

> On 2023-02-15, at 20:26:09 EST, Ed McNamara wrote:
>
> Thanks for replying Graham. I guess I wasn’t clear in what I was asking. Two of 
> the threaded ends of the shrouds have right hand threads and two have left hand 
> threads. I know the turnbuckle has both and that the stubs (technical name?) 
> threaded in at the opposite end of the turnbuckles  have to have the opposite 
> thread of the shroud end. But why would the shrouds not have all LH or all RH 
> threads. I can’t think of a rational explanation for 2 of each but wonder if I’m 
> missing something. 
> 
>