I do this stuff in the rigging shop all the time on "The Punisher" (visualize a 30 foot I-Beam, a couple of load cells, some 8mm BB chain and a 40,000lb hydraulic ram).

We test different splices, knots, and blocks and their effects under pressure.

Watching a bowline cut itself is interesting. Testing working load on a new block is even more fun.

Checking the integrity of a eyesplice on a 27,000lb rated piece of spectra usually clears the room....

high-modulus fibers - known as spectra, vectran, technora, etc.