The January issue of Practical Sailor had an article suitable for a few lines in Post-Apocalyptic Boatbuilding.
It notes that retired climbing ropes (they call them ropes) usually have very little UV damage or wear. And are retired early and often. While they stretch a bit more than our top low stretch lines, they have many uses where stretch is expected or even useful.
This gets you a peek. http://www.practical-sailor.com/issues/37_61/features/Testing-a-Dynamic-Traveler_11899-1.html
There are 5 different kinds of ropes, but I gather that single dynamic are what we want.
I’ve used ex indoor climbing gym dynamic (stretchy) ropes for an anchor bridle snubber for years. It is very stretchy and does provide a bungee jumping sort of experience in very strong wind gusts. But I do think it reduces shock loads on the anchor.10mm rope on a 7 ton, 40 ft cat.
Evans Starzinger, a very experienced cruiser uses them for this use and for Traveller control lines to reduce shock loading for accidental gybes.
The knots are different and heavier for climbing. In a jam you can use hardware store rope. Had an x climber on board and used some climbing gear for minor things. I firmly believe that when in doubt Aviation Grade does the best job.
Being an ex climber I agree with this comment but I think for sailing purposes static lines would be much better than dynamic lines. Mooring lines would be good using dynamic due to the high stretch they have. Peter