HOw much do various knots weaken a line

[Kukri]

Right, I’ve just tied an Estar hitch round my fountain pen… “ I learned a new trick today!”

 

[zoidberg]

Here I am at 0100am, learning new knots more than 65 years after my ould mum sewed my Wolf Cub Proficiency Badges onto my green sweater.
How time flies....

 

[thinwater]

Google must be broken today.

• You cannot state how much a knot weakens a line without knowing the exact type of rope, state of wear, and whether it is wet or dry. Figure about 60% loss to be safe, though many knots are better.
• The rope breaks at the first sharp bend.
• Halyards are sized for stretch, not thrength, and they fail due to chafe and fatigue. If the knot fails, the rope was grossly undersized. This is true of most rigging. Docklines subject to wakes are an exception.
• I'm a big believer in knot over splices for many applications, but splicing Dyneema is dead simple. There is no reason to use a knot except to terminate a lashing, where enough half hitches are well proven. A triple fisherman's knot has also been tested.

 

[zoidberg]

When I started rock-climbing - Glencoe, Arrochar - in the early 60s, many of the climbing club members had boots with Tricouni nails and carried hemp ropes. I'm fairly sure I recall one or two had Alpenstocks.....

Within a year or so, 3-strand nylon rope became common.... slings were tied with Fisherman's Knots..... and some of the more progressive guys began using reamed-out truck wheelnuts threaded onto slings for 'protection'. There were a few strange knots in use around then, and one of them was the Left-Handed Duntocher Ham Hitch With Two Half-Whatsits. I'm offering that as a candidate to the magisterial Ashley Book Of Knots, or ABOK.

It seems faintly ridiculous to describe the behaviour of a crew of coarse apprentice welders and fitters from the Clydeside shipyards and machineshops as a 'culture' but there certainly was a consensus that one simply didn't fall off. None of us trusted any of the knots, nor any of the ropes, to save our sorry pink butts in the event of a seriously bad decision.

Mostly, we got it right.

I s'pose today that process of 'Should I or shouldn't I' and weighing the consequences might now be called 'Critical Thinking' but whatever it was, it served us well. I'll stick with it.....

 

[Stemar]

I still reckon that the only time a rope should be stressed to anywhere near its braking strain is emergency towing of large vessels. Large in this case may be a deep sea tug towing a panamax+, or the GAFIRS RIB pulling a heavy yacht to keep it off Bramble Bank in a storm because they can only carry a certain amount of rope of limited size - it's a matter of proportion. If you're breaking your mooring lines, I can't help thinking that there's something wrong with those lines or the way you're using them. Either they're too old and worn, they're undersized or not elastic enough. Or you're doing something wrong.

I see a lot of boats tied to our club pontoon with a metre length or less of line twixt pontoon cleat and boat cleat. That's asking for trouble, even in good weather, because there'll be some muppet along sooner or latter in a little mobo, just off the plane and throwing up a 2 foot wake (how TF does a 20 foot boat do that?) and setting both pontoon and boats leaping around. Oh, yes, and one or two of those boats with short lines are using retired halliards as mooring lines. No wonder they break, or the cleats get wrecked.

I always used to take the stern line on my Snapdragon to the outside cleat on board, and preferably to a cleat one the pontoon at least a couple of metres aft, to give a bit of length (=elasticity), and I'd pull the stern in fairly tight, as it made boarding to the cockpit easier. That meant I had a decent length at the bow too. Now I've got a pretty much rectangular cat, I take both bow and stern lines to the outside cleats on board which, again, gives me a good length of line to stretch when it needs to.

 

[KeelsonGraham]

Its very unprofessional to not pass the eye of a mooring line ashore! A seamen always pass a spliced eye ashore and makes up the loose end on deck, not the other way round. Thats for MOBO's who know [--word removed--] all about ropes, knots and splices.

Bowlines are for boy scouts!!! Splices for seamen.

When was the last time you saw a bowline on a mooring line passed down from an MN or RN ship.

1 rope 1 job.

Really? sounds like tosh to me. I hope you were being tongue-in-cheek. No-one in their right mind is going to criticise a yottie for passing a rope end. Ever heard of OXO? That’s what they teach on RYA courses.