[Milsurplus] Rope Snubbers?

[KD7JYK DM09]

I am looking for snubber similar to what is shown in the picture, BUT, if
possible, for 1/2" rope.  Does such a thing exist?  I've had no luck
searching the web for several days, but did come across four of these used.
I need the following, preferably twice this size, any suggestions or sources
that I can buy outright?:

http://thumbs.myopera.com/sz/colx/ai4wm/albums/4948222/100_0992.jpg

I don't require Military, there MIGHT be something along the lines of other 
rigging, but I need something for rope, something I can run out, tighten a 
line by hand, no tools and not absurdly expensive.

Thanks!

Kurt