Sunday, June 24, 2007

The Mythical Z-Drag

Most boaters have heard of the Z-Drag – they may have even thought to themselves at some point, “This might be one of those times when we need that z-drag thing”. Very few though, (at least in the novice/intermediate ranks), it seems actually know how to set up a Z-drag. And for good reason – you just don’t need to use one all that often. In my boating career, I’ve only set up one z-drag, and I’ve seen lots of pinned boats. Most boats can be unpinned with good old-fashioned elbow grease and/or vector pulls. Exhausting those options though, and assuming you still want your boat back, here’s the simplest Z-drag you could assemble. At a minimum you will need a rope, three prusiks, and two carabiners (preferably locking). The prusiks and carabiners should be in your PFD – it doesn’t do you any good if they’re in the pinned boat.

Jon's basic pin kit shown here is not expensive:
8' of 7mm rope:$3.36 (Tree saver strap, this is the one that goes around the tree.)
12' of 5mm rope: $3.60 (Makes two prusiks about 3' long, 5mm bites better on your typical 1/4 through rope)
2 Carabineers: $12.00
1 Locking Carabineer: $15.oo
2 Nylon wheels, $12
Roughly $35 dollars in addition to the throw bag you already own, remember the post about essential gear here.

Prussic loop completed

Tie one end of the throw rope to the pinned boat. Now hold up a second, if you are going to span part of the river with a rope, you need to make sure that kayakers coming from upstream have some warning and can pull over before they are clotheslined by your rope. Okay now you can proceed with tying the figure-eights or bowlines to the security bar, both of which are good knots for this purpose. Attach a dampener to the rope – this could be as simple as hanging a pfd or shirt over the rope. If you apply enough force, those security bars/grab loops on the boat can pull out. The dampner knocks the security bar down before it reaches you or your friend’s face. Tie one of the prusiks around a tree and clip your first carabiner to it. Run the throw rope through this carabiner. Now run that rope through the second carabiner and attach your second prusik to the second carabiner and the first length of rope via a prusik loop. Pull. (See picture below)
Using two pulleys in conjunction with the carabiners is admittedly a more efficient option – some of the mechanical advantage is not sluffed-off through friction. There is also the option to use a third prusik as a break for extended pulls. There are certainly better z-drag systems, this is just the most simple.


Scott said...

I found the illustration to be very informative and helpful.

Scout said...

Those are 2 Ryans in that first picture w/ a pin at the confluence of the Papallacta and the Quijos, Ecuador. Scout (me) is trying to look cool for the photo.