Monday, 24 February 2014

MLD Trailstar guy line slips - how to secure the lines with the standard line locks

Before Christmas I treated myself to a tarp - the Mountain Laurel Designs Trailstar which is said to be a marvelous tarp and the best thing since the last quite good thing.

I pulled a face therefore when I read on the internet just now of a  catastrophic trailstar collapse event, by a fellow wild camper up Helvellyn in, shall we say, more than a light breeze.  Basically, he trusted the line locks provided with the tarp, and they slipped making his tarp collapse and letting him down like pair of cheap Japanese braces.  He wasn't injured, and had a back up bivvy.  But in the process the tarp got torn and he swore a lot.  No, I mean a lot - I saw the video he made from his backup bivvy.  He was indignant to say the least.  No it was worse - he lost some kit to the wind.  Titanium kit.  This is unacceptable and I panicked as I haven't even tried my new tarp out yet.  Checking a few other blogs, it seems the standard locks are known to be a bit suss when using thinner cord, but should be OK, with the 3mm supplied.  Well, evidently not, so I thought I'd have a look at this before venturing out with it.

I've examined the line locks and I think there's a couple of things to try before giving up and getting some other locks.  I've taken some pics to explain.

Here's the normal layout with the loose end of the line at the top and the tensioned line at the bottom, below left.  You can see that the loose end goes up through the rear hole of the line lock, over a plastic bar and down through the front hole. It has to be be this way round as explained in the third picture.

And here's a closer look.  On the left you can see the v-groove, indicated with the screwdriver tip, in which the two sections of the line sit under tension.  The loose end is in the bottom of the groove and the tensioned end presses down on top of it (or technically underneath it as these photos show the underside of the lock), and this is how the tension is maintained when all is well, but if the wind is buffeting about and blows the tarp in such a way that the tension is reduced briefly, the loose end can begin to slip (as per the right pic because there is nothing pressing down in the groove. Our hapless friend with the collapsed tarp thinks the friction of this system may have be overcome by strong gusts, but my guess is it was more to do with momentary release of tension that started things off!

Then when the wind stops the slack introduced will stop the tensioned end gripping the loose end and everything gets worse quickly, and all your pans blow away!

So, how do we deal with it?  Well the first trick is to take the loose end of the line and yank it back towards the tarp (see below left) so it doesn't sit in the V, and let the tensioned end sit in the bottom of the V.  Then what happens is the loose end of the line jams against the side of the V groove channel under the pressure of the tense line (see below right - loose end indicated by screwdriver agin).  This is a pretty solid arrangement and doesn't lose its locking effect if the tension is momentarily lost, but I don"t know how it will be affected by moisture, and I wanted more security....

 So, I found another way to arrange things.  Firstly, peg out and tension as normal.  Then grab the two line ends, between the peg and the lock, with your right hand, and the lock or corner of the tarp with the left hand and push them together - this will be pretty tight if you have already tensioned, but should be possible.  By doing this, you can make a loop of cord push up through the lock as below left.  Now, with the index finger of your right hand, pop the loop over the tab of the lock as below right, gently pulling the loop tight over the tab.

Now pull the lines fully tight to secure the loop as below left.  This is now pretty secure, but to be doubly sure yank the loose end of the line out of the v groove, and wedge the tensioned end in the channel as in method one, see below right.  Note, if the tension is making it tricky to slip the loop over the tab, you could peg-out and tension-up (this is sounding like a heart clinic now...), then slip the guy line off the peg. Carefully do this loop trick making sure not to alter the line length, before putting the guy-line back on the peg, pre-tensioned.

The final posture of the lines will be as below.  Its taken me about 15 minutes to write this and arrange the photos, but takes about 10-15 seconds to actually do it!

Hopefully, this will withstand the wind when I try it out.  I'm thinking of going to the Lakes next weekend and I was going to take the Terra Nova, but I think I might try out the tarp, with bothy bag back up of course!  I'll report back on how it worked out, and if its not as good in practice, I've lost nothing.

Finally, I have just discovered a really useful knot that looks to be about the perfect guy tensioning knot if you want to get rid of all the plastic bits completely - it's called the Farrimond Friction Hitch (google it - there's loads of descriptions and videos) and it's really secure whether tensioned or relaxed, but is also a quick release knot too.  It's effectively a Prussic knot on a bight - have a look if you are a knot fan.

UPDATE:  I took the tarp out a week or two after this post, and one of my dogs and I spent a very windy night camped on the Shoulder of Wether Hill.  I didn't get a lot of sleep out of being afraid the tarp might blow away or the guylines slip etc.

In fact the tarp stayed put all night and even though one peg pulled out of the soft peaty ground, the guyline never slipped and I was able to re-peg from inside, so it looks like this method works if you find the lines slipping.