Comparing techniques used for eye splicing double braid polyester (=Class 1)

[s/v Jedi]

I don't think the tail will move under tension either. I think it will move while not under tension, flapping around etc. and that it will then bunch up against the thread. Because that is why the thread is there: to stop that movement. From that situation, during the next tensioning cycle, it needs to move as it tightens and this is when I fear the thread cuts into the fibers... because the tail has moved a little.

[s/v Jedi]

We're on....

[s/v Jedi]

I started a new thread about my halyards here: http://www.cruisersforum.com/forums/...ml#post2364935

this is for both Dyneema and polyester double-braid halyards

[s/v Jedi]

I just finished the first splice in the Samson XLS Yacht Braid 7/16" following the Samson instructions. The core that I ended up cutting off was exactly one fid length

The splice is a beauty:

[Alan Mighty]

Originally Posted by s/v Jedi

The core that I ended up cutting off was exactly one fid length

Thanks for the data point on the amount of core you cut off.

Originally Posted by s/v Jedi

The splice is a beauty:

Ahh! A Wichard thimble shackle.


I've not used one before.


What is the crotch angle (the angle between the two legs of the splice)?


By eyeball, the crotch angle looks in the 30 - 40 degrees range. I'd be happy if you could do a better job of measuring for me.


A wire rope thimble (i.e. a thimble originally designed for wire rope but now sold for use with laid or braid rope) has a crotch angle of about 40 degrees. That crotch angle is too large for rope splice - it creates a tearing force, a force that tears the two legs apart. Better to have a smaller crotch angle of 14 - 26 degrees (26 degrees is about the biggest crotch angle that is acceptable if you are subjecting your splice to a high cyclical load).


The apparent advantage of a Wichard thimble shackle, compared to a wire rope thimble, is that you could make your splice loop longer and the thimble shackle would stay in the splice loop. In contrast, if you use a wire rope thimble and bend its legs to give a lower crotch angle, the thimble is at risk of falling out of the splice unless seized on the rope.


If you are interested in exploring the tearing force and how it changes with crotch angle, and if you know your likely working load (in kg.force) and the effective diameter of that shackle pin (in mm), I've attached a worksheet with which you can play. (it's really an *.xlsx that I've quickly renamed to *.xls - your spreadsheet program may or may not complain about the extension or you could rename it to *.xlsx).


You can input just the 'working load' and 'crotch angle'; or 'pin diameter,' 'working load', and 'flattened loop length' or 'loop circumference'.


Attached: splice geometry.xls, about 14 KB

[Alan Mighty]

S/v Jedi:

If you used a Wichard thimble shackle 10 (10 mm shackle pin) then the diameter of the pin around which the splice loop is made is about 20 mm.


I've corrected minor typos in that *.xls: see attached splice geometry.xls (still about 13 KB).

[s/v Jedi]

I did another Samson class I eye splice in Samson 7/16" XLS and documented it in a blog post with plenty pictures.

Again the core was 1" longer than the cover after balancing the rope and I ended up cutting exactly 1 fid length of core off just like the previous time.

Here is the blog post:
Samson eye splice for class I double braid rope - s/v Jedi

[Seaworthy Lass]

Originally Posted by s/v Jedi

I did another Samson class I eye splice in Samson 7/16" XLS and documented it in a blog post with plenty pictures.

Again the core was 1" longer than the cover after balancing the rope and I ended up cutting exactly 1 fid length of core off just like the previous time.

Here is the blog post:
Samson eye splice for class I double braid rope - s/v Jedi

Hi Jedi
Excellent write up.
I like your tip of inserting a tiny fid to safely cut the cover strands for the taper. I have been using small nail scissors the last few times.

Did you use Samson's method for "tapering" the core? They instruct to cut off half the strands where the core coincides with X. This abrupt taper is the main thing I don't like about Samson's method. It is bery easy for this to mobe slighly into the eye portion and create a sharp transition. I have been gradually tapering the core. It makes the final bury slightly harder, but not overly so.

SWL

[s/v Jedi]

Originally Posted by Seaworthy Lass

Hi Jedi
Excellent write up.
I like your tip of inserting a tiny fid to safely cut the cover strands for the taper. I have been using small nail scissors the last few times.

Did you use Samson's method for "tapering" the core? They instruct to cut off half the strands where the core coincides with X. This abrupt taper is the main thing I don't like about Samson's method. It is bery easy for this to mobe slighly into the eye portion and create a sharp transition. I have been gradually tapering the core. It makes the final bury slightly harder, but not overly so.

SWL

I use the core tapering method as from the official Samson instructions... step 7A in this document: http://www.samsonrope.com/Documents/...Splice_WEB.pdf

it tapers per strand...

[Seaworthy Lass]

Originally Posted by s/v Jedi

I use the core tapering method as from the official Samson instructions... step 7A in this document: http://www.samsonrope.com/Documents/...Splice_WEB.pdf

it tapers per strand...

I missed that the written doc was different to their video.

Check out the tapering used here about 12 minutes into the video:

https://m.youtube.com/watch?v=cmGMP23vAUw

[s/v Jedi]

Indeed. The thing with a video is that you get one persons way of doing it so I always use the written instruction as the guide and use the videos to check out details