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Discussion Starter #1 (Edited)
Sampson has performed UV testing on Amsteel that suggests a useful lifespan of 5-8 years, depending on how strength you can afford to loose. That is always the compromise with rope; strength fades starting day one. If you over size a bit, however, that life can be very long indeed, exceeding the fatigue life of wire, but now we're getting off topic.

However, while brommel splices do not require stitching, bury splices do, and many projects require a bury splice at one end. Given that the thread is going to loose strength much faster, how do we know how much thread is enough? Yes, some of the thread is on the rope and thus protected.

Thoughts? Since the thread does nothing but prevent the splice from walking before the load comes on, perhaps the strength requirement is so minimal as to be almost negligible. Further, I'm going to guess that the line becomes less slippery over time and slippage even less likely. Perhaps that last point is it; if there is enough stitching to hold the first day, it will always be enough.
 

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The lock stitching buries pretty deeply into the Amsteel. I wonder how much exposure it actually has to UV. If you are pulling your stitches tight they will disappear.

You can see this most clearly if you lock stitch in a contrasting color.
 

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I haven't seen any studies on it, but my guess is that the effect of UV on the thread is insignificant. Any amount of pull at all by the threading immediately pulls the finger trap closed, after this the line holds itself. The thread is really there just to limit the ropes sliding against themselves under no load conditions.

To try and limit this I still use dyneema whipping thread, or dyneema fishing line, but I really don't think it is necessary. But better to be safe.
 

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One can also periodically treat ones lines and splices with a urethane coating to extend its useful life, for example Maxijacket Urethane Coating, which can be used to color code lines as well.

FWIW...
 

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HyLyte, does that change the feel of the line?
Jim--

It makes the line feel "slick" to the hand. Note, however, that such coating is normally only used on line, or the portion of lines, that have the covers stripped off and are not normally handed, or on splices. For example, we have replaced our wire runners with 5/16" spectra with the cover stripped for the roughly 35 feet between a point about 3 feet above the deck at the turning blocks on the quarters to the mast. The portion of the runners through the turning blocks and to the secondaries for tensioning and setting up the runners still has the outer covers which protect the core from UV. The spectra is twice the strength but less than half the weight of the wire runners with the added advantage that it doesn't chafe the boom when they come into contact (and they do from time to time). We have also used spectra for our 2nd and 3rd reef lines with the covers stripped off save at the point at which the lines pass through the sheaves on the underside of the boom at the mast and down to and around the reefing winch. One quarter inch Spectra weighs almost nothing so have the lines reeved has no effect on the sail (although we only reeve the 3rd reef when we're going to be off shore for some period).

FWIW...
 

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Discussion Starter #7
How about Maxijacket on Amsteel or STS-12 lifelines? If chafe is managed, UV might be the limiting factor. Refreshing the coating every few years would be light work.
 

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Maxijacket isn't exactly a cheap option at over $50/qt.

The lockstitch, as said above, is just for when the line is not loaded, they provide zero strength. After a line has been loaded and used for some time, the outter core compresses the inner, and creates a texture of the inner core, further increasing friction.

If you're worried about it, just re-stitch it after 8 years. But most of us have other projects to work on instead of worrying about something that perhaps, maybe, might be an issue.
 

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Discussion Starter #9
Maxijacket isn't exactly a cheap option at over $50/qt.

The lockstitch, as said above, is just for when the line is not loaded, they provide zero strength. After a line has been loaded and used for some time, the outter core compresses the inner, and creates a texture of the inner core, further increasing friction.

If you're worried about it, just re-stitch it after 8 years. But most of us have other projects to work on instead of worrying about something that perhaps, maybe, might be an issue.

I hear everything you're saying.

a. Yes, $$, but very little is needed, far less than a quart. You can buy 4 ounces for $7 + frt.
MaxiJacket Coating

b. I was actually thinking about deterioration of the entire line this time.

And actually, most projects are "might, maybe...!" Just something to discuss on an internet forum.
 
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