Splice the Mainbrace (a covid shutdown article from Jim)

posted Jul 25, 2021, 5:17 PM by Posts Editor   [ updated Jul 25, 2021, 5:17 PM ]
Jim Stockton is caught up in the joys of the Melbourne lockdown and has been using his down time productively - here is a tale redolent of hemp and stockholm tar... (or maybe not).

For 25 years I used galvanised wire for the rigging that holds up my mast, replacing it periodically when it began to corrode. I’ve avoided stainless steel because there is often no warning that it is about to fail. Meanwhile, I’ve learnt that the Enterprize uses rope extensively in its standing rigging and that small boats were using hemp not that long ago, so is it feasible to use rope on a small boat? Hemp rope is still available, but expensive, are there other possibilities?
Ultra-high molecular weight polyethylene is the new black in rope fashions. Don’t be put off by the chemistry; it’s sold under a number of brand names that are much easier to remember.
It’s strong, doesn’t stretch much and you only have to sell your mother to buy some. It is braided and has a slippery, slimy feel so it probably does not hold knots well. If you believe the shore bandits who run boat chandlery stores, it requires special hollow, pointed tools called fids for splicing and you need a different fid for each size of rope. All this costs money, and no member of our club willingly spends money, especially as you’ve already traded your mother for the rope.
The other cute thing about shore bandits is that they only quote the breaking strain of the rope, not the rated capacity for normal use, which is generally one-sixth of the breaking strain. This means that the 900kg breaking strain of the rope I bought for the standing rigging on a 5 metre Oughtred Ness boat has a rated capacity of 150kg, which is ample. If the load on the rigging is more than 150kg, then I’m in trouble.
It turns out that the fid claim is doubtful. Courtesy of a couple of websites, all you need is a double ended knitting needle or something similar that will slide easily through, and inside, the outer braid. Here’s the arrangement that I used, with the needle joined to the rope with filament tape (which is used in packaging)
 

For good descriptions of the splicing process, take a look at these websites.
https://www.instructables.com/Spectra-Loop-Splice/
http://cofc.co.nz/docs/dyneema-spectra-splicing-manual.pdf
Here’s an example of an eye splice. It’s neat because the working part is fed back inside the standing part after being passed twice through the standing part. I know that sounds silly but the websites explain the process clearly. The only modification I have made was to cover the whipping at the join using heat shrink tubing (as used in the electrical wiring on boat trailers).


 How well does it work? I’ll let you know after the next sailing day (unless I win the Broken Oar award for the third time).
Meanwhile, you really can tell people that you could splice the mainbrace with a knitting needle.
Note:
Wikipedia tells us that “Splice the main brace” is navy jargon for “Issue alcohol”, so things could get confusing is you start handing out knitting needles instead of drinks.
JS