SMB Line Shortening Trick

[emorrow]

Hello,

A few months ago I was on a live aboard in Thailand and our dive master Chris taught me a great trick for shortening an SMB line. Unfortunately when I got home I forgot to practice it and lost the knack for the weave. Does anyone out there think that the following description sounds familiar and can provide some refresher advice? The best way I can describe it is something like a chained double slip knot that allows you to shorten a 10m line to about 1.5m. One end gets fastened to a small lead weight and the other attaches to the SMB. The cool thing is that when you are ready to deploy the SMB you drop the weight and the looped weave unravels from the bottom. You then fill up the SMB and do your safety stop while loosely holding the line.

Any help greatly appreciated,
Erin

 

[vshearer]

Did it look like this?

Chain sinnet - Wikipedia, the free encyclopedia

 

[String]

It was probably a sinnet similar to one of the ones here:
http://en.wikipedia.org/wiki/Chain_sinnet

However i will add that is possibly the most moronic method to send an SMB up that exists. Its a pain to stow, can tangle, involves dropping weights around the reef so if you misjudge you smash it up, its a complete nightmare if you then have to tow the bag especially if the depth is changing.
Get a reel (or a spool if "one of them).

 

[Charlie99]

However i will add that is possibly the most moronic method to send an SMB up that exists. Its a pain to stow, can tangle, involves dropping weights around the reef so if you misjudge you smash it up, its a complete nightmare if you then have to tow the bag especially if the depth is changing.

I've seen it work well in one specific circumstance, and I'll bet the original poster saw it being used in a similar situation.

It was for a DM led group, on a wall, doing a multilevel dive. The DM sent the SMB up when the first person reached ascent pressure. Because it was a multilevel dive, the rest of us would be relatively shallow at that point of the dive, and would be continuing to ascend -- so a fixed line length works. Since we were on a near vertical wall, there isn't any issue of stuff dropping onto the reef.

 

[emorrow]

Thanks to all for responding.

@Charlie99: my experience was quite similar to one that you described. The point of this method was to deploy when at or near safety stop depth. If you take the time to mark out 5m on the line you've simplified the task of maintaining the proper stop depth once the SMB is deployed. I simply let the line run up (or down) through a looped thumb and forefinger. Keeping the line shorter than 8m I was able to harmlessly deploy it in most situations. You get the advantage of signaling to the boat or launch without having to tether yourself to a buoyant object. Say what you will, but to me inflating a buoy that you are intent on holding (or even worse have attached to yourself) is a terrible idea especially at depth. I've yet to meet a spool of anything that doesn't foul at some point, and usually when you would least like it to.

Having said all that, the Chain Spinnet is not quite the same technique. The knot/weave that I learned (and forgot, and is now driving me mad trying to remember) started with a permanent loop tied just above the weighted end. That loop gets hung over one thumb resting the weighted line across the palm. The slack end gets hung over the opposing thumb and then some Cat's Cradle like trickery ensues and you can very quickly shorten the line. A rough estimate would be that this technique halves or even thirds the number of links required compared to the Chain Spinnet.

Any other thoughts? Thanks again,
Erin

 

[String]

Thanks to all for responding.
You get the advantage of signaling to the boat or launch without having to tether yourself to a buoyant object. Say what you will, but to me inflating a buoy that you are intent on holding (or even worse have attached to yourself) is a terrible idea especially at depth.

Why on earth would ANYONE consider ever sending a buoy up attached to themselves ?! Its complete lunacy. No agency teaches anything of the sort. Its a sure fire way to end up in the pot or worse.

I've yet to meet a spool of anything that doesn't foul at some point, and usually when you would least like it to.

OK so a mess of rope stuffed in a pocket somehow cant tangle but a spool which is no more than the same bit of string around a plastic drum with no moving parts can ?!
A properly wound reel or spool cannot jam. It also doesn't form a birds nest style mess that lose rope does. (Nor does it run the risk of bouncing off a reef, getting lost if deployed in a current as you didnt have hold of it, can be sent up from depth when needed instead of waiting until shallow having already drifted a mile or so getting to that shallow depth and so on).

It really is a ridiculous method of sending up a dsmb.

 

[Randy43068]

Shortening the line to a SMB?? Isn't it on a spool???

Wind it up man!! Wind it up.



I do like how they tie those knots if that's what it's called. Had an instructor who wound the rope on markers like shown in the picture.

 

[emorrow]

OK,

So I sat down the other night and worked at it until I figured it out. If anyone is interested I can take some photos of the process and post them. I think that this knot is pretty useful for other things such as climbing or camping.

I also think there may be some clarification required here so no one thinks I'm out there deploying an SMB with the line wrapped around my neck or something. Here's how I was shown and continue to deploy SMBs using this method.

1. Between dives shorten the 7m line using this chain slip knot
2. Roll up SMB and wind shortened line around it - only takes about 3-4 winds!
3. Stow SMB and line in BC pocket
4. Get in the water and have some fun
5. Upon reaching safety stop depth remove the SMB and line from BC
6. Ensure that the distance to the seafloor is greater than length of line
7. Unwind shortened line from SMB
8. Release weighted end (I use a largish lead fishing sinker ~75g) which causes the chain to unravel automatically from the top as the line extends to its full length
9. Add air to SMB and release
10. Hang out for a couple of minutes then go up and meet the launch (I like to mark the line at 4, 5, and 6m I can easily maintain depth)

I like this method because during deployment the line goes down instead of up. If the line is somehow fouled (which can happen anytime a line is used regardless of method) it is apparent before there is any buoyant force in the bag. These factors essentially eliminate the danger of an uncontrolled ascent during SMB deployment. I own a spool and am happy to use it for some things, but for drift diving I find this technique works as well or better. Plus I have a thing for clever knots.

Cheers,
Erin

 

[scjoe]

I have seen people employ your method, but without the chain slip knot. They just wrapped the line with the weight (usually some form of clip) around the SMB. It worked just fine in recreational tropical diving settings, but without the neat knot. I would not call it moronic or ridiculous, just different than what you would typically see. Obviously, a reel gives you the ability to make multiple stops in the water column, but the statement "a properly wound reel or spool cannot jam" is one of the sillier things I have read on this board. Give any open water student a properly wound reel and they will jam it with a bird's nest in minutes, if not seconds.

 

[Puffer Fish]

I have seen people employ your method, but without the chain slip knot. They just wrapped the line with the weight (usually some form of clip) around the SMB. It worked just fine in recreational tropical diving settings, but without the neat knot. I would not call it moronic or ridiculous, just different than what you would typically see. Obviously, a reel gives you the ability to make multiple stops in the water column, but the statement "a properly wound reel or spool cannot jam" is one of the sillier things I have read on this board. Give any open water student a properly wound reel and they will jam it with a bird's nest in minutes, if not seconds.

Well String actually used the term "Lunacy", not "moronic", but it was a bit over the top.

I have seen people use that method, and while I don't recommend it, in some places it works just fine.

The major problem with String's post is that emorrow only asked if anyone knew how to do it, not if it was a good method. He dumps on him, then someone comes to his defense.. and oh joy... we are yelling at each other. Thanks for showing some restraint.