Battling our arch enemies: rust and chafe.
Not that we’re trying to make a habit out of this work thing but Rebecca and I decided to put in a few more hours yesterday, ticking off some boat tasks. While she took on the job of polishing all of the stainless steel on the boat, a time consuming but important job, protecting the metal against one of our arch enemies, rust, I decided to do a bit of preventative maintenance on our lifelines, taking on the other villain, chafe.
It’s important to keep the rust at bay.
Long time readers may recall that almost two years ago I replaced our stainless steel lifelines with Amsteel, one of the newer hi-tech lines that are available. There was some concern amongst readers at the time that the line would be susceptible to chafe and/or UV degradation. While I can’t very easily ascertain what, if any, damage the sun has done to the line, I can check on the chafe issue.
Because the main chafe points are where the line runs through the stanchions, I decided to shift each lifeline an inch or so towards the stern so that a new piece of line would be running through the holes. I could also then see how much of a problem chafe actually is. I began by drawing a pencil mark on the lifeline on each side of a stanchion. I then eased the lashing by the bow, adding a bit of slack until the pencil marks were clear. When the opposite end was then trimmed in, the lifeline shifted aft, exposing each section that had been inside the stanchions. Having now done so, in my opinion, the chafing of the line is negligible, which is as I expected because Amsteel is promoted to be both chafe and UV resistant. Needless to say, I’m pretty happy about that.
Even though the knots holding the lashing together have not come loose in all this time, I decided to put a few more points in the Black Box by lock-stiching them together with some waxed whipping twine that I had on hand. My sewing job may look a bit like the stitches on Frankenstein’s monster’s face but the lashings sure won’t be coming undone without my wanting them to.
It’s a good thing that Amsteel is slippery or I never
would have been able too untie the knots on the lashings.
You can see the tiny bit of chafe to the left of the stanchion where the line is discolored.
Almost as nice as the stitches on Frankenstein’s monster’s face, a movie which coincidentally, we watched just the other day.
I’m glad to see you’re tying the lifelines around the stanchion itself, rather than the welded loop. I see far too many cases where the line is clipped to the loop, which is wrong. (The welds on the end of the wire aren’t always strong enough to withstand shock loads; you need a thick welded plate instead of a wire loop if they’re done that way.)
So it sounds like another positive report for Amsteel, which I’m getting more and more tempted to use in the future now that it’s looking like it holds up over time.
Nice to hear that I do one or two things correctly. 🙂
I posted this, regarding Amsteel lifelines, on Sailnet some time ago. I’ve made some edits as I’ve learned a little more:
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… some sailors simply go oversize (1/4″ and even 5/16″). The strength allowence will then forgive a lot of UV and chafe.
3/16″ 5,400#
1/4″ 8,600#
5/16″ 13,700#
3/16″ seems to be cutting it thin, IMHO.
Slide 10 of the study in the link below shows the UV effect; 65% after 2 years, and then nearly flat. I would guess that the UV only penetrates so deeply, the diameter of the rope matters, and they were testing individual yarns. They also don’t mention in the rope had the Amsteel Blue coating, but I think it did (or the results would be worse). I’m guessing 75% strength after 2 years is close for 1/4″ Amsteel, with slower change after that. Perhaps 50% a 10 years.
http://www.samsonrope.com/site_files…tic_Ropest.pdf
There is also discussion that after many cycles of heavy work the line can lose ~ 40% of it’s strength, and then the loss basically stops. But lifelines see very little of this.
That being the case,1/4″ Amsteel should last 6-8 years at greater than 5,000# strength … unless there is visable chafe or some other reasoning. Of course, the SS wire strength requirement includes an allowance for wear and tear, based upon expereince. I suspect 3,500 pounds is realistic for a well-used (not corroded) SS lifeline after 10 years. So 1/4″ should be safely good for 6-8 years and 5/16″ for 8-10+ years. Hard to say. Real-world long-term testing has a lot of variables and is too expensive…
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At the time I wrote that, race commitees did not accept Amsteel lifelines; now they do, with the same strength requirement as SS, though I recall they require evidence of 5-year replacement.
More than you wanted to know, perhaps. But I think I will be going with Amsteel soon, so as you would expect, I’m certain to research the hell out of it.
What diameter did you use?
Look around for some suitable ” adaptable cotton reels” in plastic or delrin or similar and cut a slot in them, to get them over the life line and possibly reduce the side cheek that has to push through the hole if necessary, and slide them into [position around the inside face of the stancheon support hole? I wouldnt be surprised if the stancheon manufacturers didn`t make them to match for a couple of bucks a piece? they would give you a few years extended life on the life lines?or maybe use “Rescue tape” at the apropriate positions, to take the chafe?
JMHO.
Those are good options, Rob. Considering how little they have chafed in two years though, I wonder if it’s necessary, especially given that I now have essentially a brand new piece of line running through the stanchions. Even putting tape on them would require me to redo the entire job that I just did (or at least half of it), not something I’m too keen on.
Thanks, as always, for the technical info, Drew. Replacing them every 5 years doesn’t seem to be all that bad given the relatively small investment in money and time.
We used 1/4″ Amsteel for our lines. It was on sail at West Marine at the time that we bought it too.
Matt’s comment made me think and notice something; you have no lifeline across the bow. Without that cross support, I’ll bet lunch that the bow pulpit has become a weak link. If you take a running dive against the rail, I promise the pulpit will collapse over the side before the lifeline sees 2,000 pounds. There is only one 1/4-inch bolt anchoring the inside and it won’t hold. It will also bend. Perhaps the front lifeline is in the way–actually, I know it is–but it is structurally required.
Arguing over whether the weld can hold 5,000 pounds–it can–is completely beside the point. The stress won’t get that high for several reasons:
1. Without the bow lifeline the whole works is going to leeward.
2. There really is no impact force beyond the 5,000-pound rating; the stanchions will bend and the force will come on gradually.
3. The other end of the line is attached via a pelican hook to a similar loop near the transom.
4. If we imagine the boat sitting vertically, the wieght on the transom and the bows pointing up, do we think we can hang 5,000 pounds from the bow pulpit, without it bending aft? What about the same logic applied to the stern pulpit? Less than half, I think, since there is no cross bracing.
This is why the line needs to go 360 degrees; things will bend on impact, but the loop will remain intact and the sailor will be retained. I’ve seen some badly bent pulpits and stanchions, but the lines were intact.
I’ve actually added bow gates, which use make use of the loop. I feel the safety of reasonable access for crew on-an-off at the bow is an overriding factor. Your math could vary on that one–at the time my bow crew was 12 years old and stepping over the rail just wasn’t working!
I don’t know why there is no lifeline there. There never was one when we bought the boat so we never added one. Having viewed other boats with one has made me consider it. I hadn’t thought of it as a structural element though, solely as a safety thing.
I bet the PO removed it because it was in the way. It’s annoying every time I go to haul the bridle back in.
I think I may go with 5/16-inch Amsteel, just so it will last longer (not initial strength, not hardly). It seems it would fit easily. Perhaps just on the upper, and stay with 1/4-inch on the lower.
You know, you may chose to replace only the upper at 4 years and both at 8 year. Just thinking.
And thank you for having patients with my longer comments! I enjoy the conversation and I keep learning.
If I could get my hands on some Amsteel down here I would add that forward lifeline. Strangely I do not see it in any of the chandleries! I’ll keep looking.
5/16″ would easily fit and is probably a good choice. The cost difference is probably minimal. I just don’t think it was available (in stock) at the time I purchased mine.
Definitely the top lifeline takes more abuse. It is the only one that ever gets grabbed. So saying that, replacing them on the timeline you suggest might be the way to go.
And keep posting… you add a lot of value to our blog!
Oh Matt, you answered my question before I could even ask it! I was wondering why the loop wasn’t used and if that’s not what it is for, what IS it for.
Also – stainless steel rusts?? I thought the whole idea of stainless steel was it DIDN’T rust.
Stainless only lives up to its name when it’s exposed to oxygen. It corrodes like crazy in moist, anaerobic conditions, like the gap between the hardware and the deck…. or the tiny voids left behind a not-quite-perfect weld bead.
That’s part of why you have to be careful with welds in SS- if done perfectly, they last forever, but slight flaws can lead to hidden corrosion. So on anything highly loaded, you design it with way more weld area than the math says you need, so that it’ll still hold after a bit of crevice corrosion. Little wire loops don’t meet this criterion once they’ve been in service for a decade or two; they’re better off being used simply to stop the lifeline from slipping down the stanchion. If you want to use the wire loops, that’s fine, just be sure that all of the weld beads are perfect (which usually means taking a few to the shop for professional touch-up).
Drew’s point about the strength of the pulpits and stanchions themselves is a very important one. They are rarely strong enough in bending (every single set I’ve seen are too slender). But if they’re made of good alloy and welded properly, they’ll bend without snapping, so the lifelines still catch you, and you end up replacing a bunch of stanchions at the next port.
Stain-LESS, not rust proof.
Mike – I guess I am thinking of the kitchen where I have all stainless steel utensils and baking sheets etc. because aluminium rusts but none of my stainless rusts at all, ever. I realize I am not exposing anything to salt air but I still thought that stainless never rusted.
I wish!
Ok, this will be funny. Me and Alabamia asking a Canadian how you pronounce something, but here goes. Chafe, like laugh of safe? Windlass, like air blowing an Irish girl or Wine d Less?
Its funny how we project familiar characteristics on things and people. I read you alot apparently with a Southern accent in my head, however on video, you’re definitely Canadian!
Thanks for keeping me distracted at work!
Chafe rhymes with safe.
Windlass: air blowing an Irish girl 🙂
Perhaps on the next video I’ll conjure up a southern accent for you.
We are probably changing out our vinyl coated steel lifelines with Dyneema this season on Our PDQ32 “Minaki” and I appreciate all the work shared by you and Drew on PDQ’s. It makes my life so much easier! The PDQ forum and your site have been valuable resources for us in our first 18 months of PDQ ownership.