Violence against cables

You recall the impotent bottle-jack debacle of course.  Well I went to Biltema (a magical place) and after long stingy consideration decided to get two 6 tonne jacks this time.  The next size up was 4, but the thought of them being too weak and having to get even more jacks convinced me that overkill was the right choice.

Got some stash

Took the wimpy old jacks off and hid them with their shame in the cupboard.  These beefy fellows will surely get the job done.

Beefcake!

Hooked up the temporarily spared victim and got to cranking.  Some tense high-tension creaking filled moments later and BANG!  We have breakage.  :-)

Feel the pain!

It's all a bit inconclusive though.  We didn't get a nice break in the middle like I wanted.  You can see that the splices are mostly intact, but it's not obvious that they didn't contribute to the break.  I had some more test pieces that I had made whilst practicing more, but even after breaking two more, I still had no clear answer :-(

I have been pondering various ways of actually measuring the tension in the cable, and even tried some, but none of them really worked.  I thought I could measure the cable stretch before it broke, and compare it with some standard stretching measurements for this size and kind of cable.  Problem is that the stretch is so little, only a couple of mm at best that it really is impossible for accurately measure, especially while you're anticipating a violent breakage of the cable.

A force gauge that can measure things like this is gonna be way out of my price range, so if I am to accurately measure it, there's gonna be more time wasting!

I found a video on youtube of a dude that had added a pressure gauge to a bottle jack.  By knowing the area of the piston and the pressure of the oil you can calculate the force required.  I might try that, but it requires some rather non-trivial modifications.

Whoops, there goes a shackle!

Service

Of course splicing isn't the only consequence of my choice of galv wire for the rigging.  Stainless steel, one might assume from the name is a magical substance and free from the wroth and detrimental effects of corrosion.  In reality, not quite.  It certainly stays more or less shiny, but stainless steel's corrosive effects require the presence of oxygen.  Get seawater and stainless together in an anaerobic environment and watch the fun begin!  Galv, is certainly more susceptible to corrosion, and perhaps that's even a feature.  You don't assume that it won't rust, so you plan for it. And, when it starts to rust, you really notice it.  As long as you can sort it out soon, it is usually only cosmetic.  But galv isn't shiny, and it's not cool, so people don't like it.  It is cheap though, and I'm all about that!

Traditionally galv cable is treated against corrosion by what's called worming (not needed on smaller cables), parcelling, and serving.  I won't go into worming since I'm not doing it.  Basically what that means is you slather the cable in slush (usually a mixture of tar and linseed oil), then wrap it in long strips of tarred cloth, or cloth tape (parcelling), with the lay.  Then you tightly wrap that with tarred twine using a device called a serving board, or a serving mallet, against the lay.  Finally on top of that, you paint it with yet more slush, this time mixed also with some varnish and driers.  If you do all this well, and remember to re-apply more slush every year or two, you should have cable that last indefinitely.  Or so I've been lead to believe.

Sounds like a lot of work right?  Perfect for time wasting!

So I found a company that sells tarred nylon twine, which is what "The Rigger's Apprentice" told me was a good thing to use, and I bought some.  Memphis Net and Twine, by the way.  

TWINE!

Happiness is some warm twine?

I got some different sizes since I wasn't sure what would be best.  Although my bible, "The Rigger's Apprentice" is super awesome, it can sometimes be vague, or even contradictory in its details.  It's a good guide but you definitely need to experiment to figure out the details.  (maybe that's the intention?)

Plus, the twine is sold in weird sizes which don't correspond to the diameter or anything reasonable, but rather the weight (in pounds) of a certain length.  Americans are weird.

I can't remember the other sizes, but the one I settled on using was #30.

Now I had to make the serving mallet to apply the twine tightly to the cable.  The bible has many different drawings of a serving board/mallet, each different from the next, with no concrete information.  But I had a wooden mallet so I tried to replicated the one that looked like that.  The theory is that the twine must be wrapped very tightly, and the mallet gives the required leverage for that.

Looks ok

I cut a groove in the top of the mallet, like in the pictures, and attached a fancy spool holder!

One of my favourite knots, the icicle hitch

I stretched the cable between two points nice and tight and gave it a burl.

The twine is wrapped around the handle to give an even tension

OMG, service?

I didn't bother with the parcelling, or any slushing.  Just wanted to get the feel of applying the service. It's a bit tricky to start off since you have to wrap the service over the end of the twine.  Likewise, ending the service requires some more trickiness, which I won't go in to now (how annoying of me!).

Serviced cable around a thimble and snug in the vice.

Of course at this point I realised that all the galv thimbles I had bought were now useless.  They were 6mm, which made perfect sense at the time.  Thimbles to match the size of the cable right?  Of course I forgot all about the service.  The twine I had chosen was almost 2mm in diameter, so I figured that with all the stretching and compressing of it, it would probably be safe to go with 8mm thimbles for a nice tight fit.  Also one extra thing I didn't think about when I got the galv thimbles was the fact that unless I also had galv turnbuckles, they'd have to make contact with stainless.  And even if I got galv turnbuckles, unless I replaced the chainplates (not right now thank you) then a galv turnbuckle would be in contact with stainless too.  Why is this a problem might you ask?  Well apart from the fact that it's a little more difficult to tar, parcel, and serve thimbles and turnbuckles, the contact of the two different metals would lead to galvanic corrosion, especially bad in the presence of a salt solution (aka seawater).  So I figured that using stainless thimbles that would never come into contact with the galv cable under its protective covering of service and slush, I'd be OK.  Plus, I'd already bought a bunch of stainless turnbuckles.

The metal squid!

The quest for new rigging

So for some reason I decided that it would be a good idea to replace all of the standing rigging on the boat.  Well, that idea in itself isn't necessarily a bad one or a waste of time.  I have no idea about the origin or state of the existing stainless rigging, though it looks fine enough.  For all I know it could be original, over 40 years old!  Probably not, but hey, who knows?  So like all my time-wasting activities, it started with good intentions, and cheap intentions, and more than its share of the old "How hard could that be?"

After researching how much stainless cable and terminals cost, the miser in me decided that galv steel would be a fine alternative.  After all, it was more or less the same strength, and has been used extensively in the past by sailing vessels of all types with great success!  If it's good enough for them then it's good enough for me right?  Once that decision was made the whole train started a-moving.

Of course stainless rigging might be more expensive, but there is a reason it is so common, apart from its shininess.  It's relatively easy to set up and relatively maintenance free.  "Bah!" says I, "How hard could it all be?"

Well first there are the terminals.  Swages?  Nah, too much equipment required.  Poured sockets?  Maybe, maybe.  Cable clamps?  No way!  Ugly!  What about splicing?  Oooh, traditional, difficult, and oh such a waste of time!  Bing!  We have a winner.  So I gets me "The Rigger's Apprentice" for a look see.  Liverpool splice in 7x7 cable, too easy mate.

So now I need some cable.  The old rigging is all 5mm 1x19 stainless, with a breaking strength of 2100 kg.  Ok then, something stronger than that.  May as well go up a size.  After much searching I found a company in the UK (Tecni-Cable) which would ship to Norway (can't get anything here!) and had at it.  Bought 100 metres of 6mm 7x7 galv cable with a breaking strength of ~2300 kg. That'd give me a bit of a buffer to offset the slightly weaker splices.

Here it is in all its glory!

In my foresight I even remembered to get a bunch of thimbles to go with it!  Now surely there was nothing in the way of my first splice!

Failed attempts at securing with wire

Hmm.  How do I get this cable to go around the thimble?  Of course the rigger's apprentice had gone on about needing a rigging vice.  But I looked them up and they were really expensive.  That's not what I'm about.  I can make one.  More time to be wasted!

Yet another vice to be added to the long list ;-)

There we go, what a fine device.  We'll be splicing in no time.

And the Lord Brion Toss spake thus...

Reading from the good book.  That's a sharpened awl for a marlinspike.  A little beverage assistance visible in the background.

Meh?

So I managed after much sweating and sweating to get something that pretty much, kinda looked like the illustrations in the book.  Now I was starting to get an idea of what I was getting myself in to. More practice required.

It was at this point that I started wondering if my splices would actually be any good.  My unshakable belief that splicing would be as easy as falling off a log was starting to be gently dispelled by reality.

What I needed was a way to test them.  A splice destroying machine!

BEHOLD!

So much time wasting later, I had something I was fairly confident would be able to exert the required tension on the cable.  I got two 2 tonne bottle jacks and mounted them on top of two columns each made of 4 45x45 mm wooden beams.  Put a bunch metal ties to brace it all, and sundry attachements for holding the victim and there it was.

If I could break it, and the break wasn't at either of the splices, we'd be right, right?  In theory anyway.

The first victim for sacrifice

Put him in the rack!

I put as much tension on the cable as the jacks could manage and...nothing.  Well, a lot of nerve-wracking sounds, but no breakage (save for a minor stretching of the cable and thimbles).  Now I'm far too cynical to rejoice at the ultimate supreme strength of my splices obviously proven by this lack of breakage.  Two 2 tonne jacks I figured, ought to be able to to put 4 tonnes of tension in the cable right?  Or was that 2 tonnes of tension?  I'll admit, it's been a while since high-school physics.  In any case, it wasn't enough.  I'd chosen the 2 tonne jacks with the same miserly attitude of all my purchases.  They were the cheapest I thought would do the job.  2 + 2 = 4?  And with the cable rated at 2300 kg I figured that'd be plenty of wiggle room.  But I guess I couldn't pump them up evenly enough, or something else in the design got in the way, or I am an idiot.  Probably all three.

Well I'd have to come back to my cable destruction later.