Why do people think knots are best when lengthening ropes?
Knots have their uses but to permanently join two ropes together it’s better to splice them.
Most any knot weakens a rope at the point it is tied.
For example, here are two types of ropes, same knots, and the percentage loss of strength of the rope’s breaking strain.
Using Double braided nylon and double braided polyester.
Bowline 44.5 and 45%
Clove hitch with two half turns, 35 and 37%
Round turn and two half hitches, 52 and 36%
Figure 8, 42 and 47%
Double fisherman’s knot, 46 and 48%
Standard factory eye splice only loses 22 and 12% respectively.
Most of you will be familiar with paracord.
The usual breaking strain is 550 lbs
Hence the popular name for it i.e. paracord 550.
The loss of strength is staggering when using these common knots.
35% to 52% pencils out as your paracord only holding 357 lbs and 264 lbs respectively. Bit different from thinking you’ve got 550 lbs to play with isn’t it?
Now look at splicing. 12 to 22%. It still holds 451 lbs and 434 lbs.
Hardly any losses what so ever.
So apart from swapping to twisted rope which will allow you to easily splice ropes, (avoiding natural fibers like sisal or hemp like the plague as they get slippery when wet and their breaking strain varies wildly), you may like to look on the Internet at the Norson splice. It’s a nautical knot and one strong way of putting eyes on the end of a braided rope.
Of course if it’s too difficult to learn to splice, you’ve still got to be thinking about every time you add a knot to a rope it will weaken it’s breaking strain. Probably why I always double my paracord when it’s supporting me especially when slinging a hammock.
Learn to splice folks.
It’s good fun and could save your life!