A test

Here is rope that you normally find in lower end retail and is fairly cheap to buy,  it comes in 100 ft coils all nicely wrapped and the rope itself is very bright in color which varies across the spectrum.

In big letters it says 1/2" IN Braided Rope.

In very small letters on the back it says 300 lb breaking strength .

It is made with a poly foam core and has a thin braided sleeve on the outside. 

I have tested a single rope and found out early that it will stretch almost DOUBLE it's length. It has served for several purposes one of which includes anchoring in moderate wind with my 3000 lb boat. I never relied on it alone by having an additional anchor out to catch it if it broke.

Recently I have found the time to try an experiment with 3 of these braided 300 lb ropes. 

Here is a picture of the test piece.

What you are seeing is 3 ropes braided the whole length and eye spliced onto the anchor chain . 

So now it's a 60 ft braided 3 strand rope with 900+ lb breaking strength that will stretch past double its length before failing. I am guessing the " strength in numbers multiplier would be about 30% per strand, making it a 1200 lb breaking strength rope. 

I honestly hope I don't have to test it's full capacity. 

I do feel it will be much safer for obvious reasons plus some other not so obvious ones.