Kris,
Are you thinking that running a 3/8" or 7/16" soft shackle through a 3/8" soft eye with cordura sheath would create too much of an acute bend in both thus derating their strength? Is there a chart that shows the minimum safe radius based on rope diameter?
Yes, to a degree. I have seen line on line connections without issue. Ultimately, you wont gain that much increase in radius using a thimble, but it helps.
I have seen a recommendation once but I can not remember where and I can not seem to find it. I do know that Samson suggests a 1:8 minimum sheave diameter, which for 3/8 would be 4". But thats on something the line is moving around.
If I finally go with thimbles they will have to be able to handle a 3/4" pin, but a 7/8" pin would be even better. Have you seen any tube thimbles designed for 3/8" rope that will accommodate those pins?
The 3/4" shackle I have in my splicing bucket has a 7/8" pin. The pin on this fits through a 3/8" sized tube thimble, but the ear of the shackle will not. You can step up a size in the thimble to a half inch where you can get the ear of the shackle through.
The larger thimble is stainless steel....
You can run any diameter line through the thimble provided it fits. The larger thimble also has an added bonus, less likely to get pulled through the fairlead. Its been so long I can not remember what diameter line is in this picture. I want to say its 5/16..