Ok rope splicing Guru’s

[Dunderbird2]

I have some double braid nylon ( not common in my part of the world) which I am going to splice. I got a 100m reel of 16mm sent to me. When I measure it the core would be 16mm (5/8 roughly) but with the cover it’s about 20mm diameter. Are these ropes sized by core ? More importantly when I work out my 21x diameter for splice do I use 16mm or 20mm.

Thanks. Know you guys can bring this one home for me !

[Wotname]

Usually it's by the cover size.
What part of the world are you in?
Did they send you 3/4" by mistake instead of 5/8"?

[Dunderbird2]

Tasmania- I am think that maybe the case.

[HankOnthewater]

I agree with Wotname's assumption that you have been supplied a larger size.
Hmmm, I could do with some 20 mm (3/4 ") double braid nylon, happy to take it off your hands.

When you decide to splice that rope, treat it as 20 mm. What is the purpose? Docking lines? Anchor rode? How big is your boat?

[Dunderbird2]

I picked up a nice para anchor second hand so it will be the rode for that. Also use it for drogue, tying stern in, spare anchor rode, and cyclone tie in if I get up to northern Australia.

[Dunderbird2]

It’s a n Arends 33 (33ft)

[deblen]

https://www.animatedknots.com/indexsplicing.php / Len

[Mike Banks]

Work on the external diameter. The splice will be longer but stronger. If you do not have a set of fids or a special splicing needle, use a wire coat hanger, preferably one coated in polymer paint.

[HankOnthewater]

Originally Posted by Dunderbird2

It’s a n Arends 33 (33ft)

Those are nice boats, particular if you got one that have been well maintained! 20 mm (or 3/4") may be a bit large for your boat, just requiring more space and weight to store. When I had a boat that size (34 ft ferro at 10 tonnes plus), I used 16 mm nylon as anchor line and 14 mm nylon as docking lines.
BTW, if you protect your line from chafe.... it is hardly ever that the rope breaks, it will be the cleats and dock fittings.

[Jim Cate]

FWIW, I'm also in Oz, and a few years ago I special ordered some 16 mm double braid nylon for our snubber. When it arrived (I was in a moderately remote area at the time) it too was way more than its nominal 16 mm diameter. Didn't measure it, but it sure sounds like a similar situation. I did an eye splice using the dimensions for 16 mm and it has held up just fine over the years of service.

I thought iit was just a shipping error at the time, but now I wonder!

Jim

[thinwater]

The question of sea anchor rode size is an interesting one. Obviously it must be bigger than anchor rode; you will face worse weather with no protection from waves. 20 mm is larger than is typically recommended, but there have been failures due to chafe and due to nylon overheating.


What do we think the working load will be in a survival storm (the only time you would probably use a sea anchor)? ABYC gives about 2400 pounds for all chain at 60 knots, but it is accepted that the actually load with nylon rode is 3x less, or about 800 pounds. But add to that breaking waves, and 2400 pounds might be light. Then assume 100 knots and loads in the range of 4-6000 pounds are probable. if the BS of 3/4-inch rope is 17,000 pounds and the WLL of 3/4-inch rope is 12% of that (2040 pounds), then 3/4-inch rope sounds pretty reasonable.


Can you fit 3/4-inch on the cleats? Do you have other anchor points? Other problems to solve.


The storage space in inconvenient to be sure, but that is what good design calls for. Also look at JSD size and strength recommendations.

[Dunderbird2]

Interesting. It’s from Whitlams . I think if you stretch it out and close one eye you might be able to call it 16mm. I put some good size cleats on boat a while back so should be ok. I think apart from weight it’s handy to have a long solid line on the boat. Probably not going to be concerned about it being too heavy when hanging off it in bass strait or tied to a mangrove tree in a cat 5 !

[Benz]

Working as a rigger, I've found that many manufacturers' nominal sizes are not actually the size of the line--New England Ropes is notorious for calling lines a different size than they are. And then some lines are a certain size on the reel, and fatten up pretty quick.
One reason for calling a 1/4" line 3/16" is that in the specs it looks like the line is stronger than all the other guys' lines, and you buy it not knowing that it's stronger only because it has more fibers. The reason for lines fattening up quick is because they are poor quality--a well-made line keeps it's diameter better.
For splicing double-braid, I recommend the Samson splicing fids--you don't have to worry about measuring x amount of diameters, there are measurements on the fids.