Safety system for 60m buoy diving.

[timm]

Hey

A few of us are looking at doing some CW diving from a buoy, and I was thinking through a safety procedure taking into account there is probably going to be 3/4 of us and just a buoy and rope.

I have had a chat with friends and come up with a couple of ideas, but any advice or expereince would be great.

We are looking at a 60m rope, hopefully in 25 m vis water and max dive times of 2m 30s. Plan is for safety diver to be meeting the diver at 25m. If the safety diver cant see the diver by 2.30, he signals to the surface who starts the procedure, now we have come up 1 of 2 options here.

1. We ony have 2kg on the line as we only need to keep it straight for CW, we have 10kg on the other end of the line sitting in the boy, rope runs through a couple of karabiners. We chuck the 10kg weight in and then can start pulling the diver and rope up, using the counter balance to even out the weight somewhat.

2. Again with a light 2kg bottom weight. Surface diver dives down to 30m, attaches and opens an FHOF (small tank and lift balloon) to the rope bringing the diver to 30m. The safety diver has resurfaced and prepared breathig up for a 30m rescue dive.

Option 3 from JM
3. Same set up as 1, 2kg, with a 10kg counterbalance. Surface diver realses the 10kg counter, and dives with it to 30m, meets the diver, and does a rescue using the FHOF to surface from 30m. (like the thinking resue no limits)

Any thoughts, opinions, alternatives would be great.

Tim

 

[samdive]

I think option 2 would be best. I don't think 10kg would really be enough to get things going, especially with the diver also trying to go down on it bearing in mind the buoyancy of the suit and I guess this is going to be in te red sea so the divers will be pretty buoyant.

However - attaching and firing an FHOF can be fairly slow and fiddly, particularly under stress so reliance on FHOF is not ideal if the person firing it is breath holding.

I'll keep thinking

 

[timm]

I was initally going with the FHOF aswell, but after talking it through the counter balance seemed the less complicated.

I am working on worst case scenario, as in diver hasnt appeared in 3 mins, so you gotta do something.

I need to test it, but was hoping the 8K difference would make pulling the rope up manageable between 2 people. Probably pull it up by pulling underwater as we have assisting in getting the bottom plate up at Salt Free.

Was thinkning if I could get the diver to the surface anything under 2 minutes from 60m, this would be good / successful and much quicker than the FHOF solution, as the FHOF dive and rescue dive would be more than 2 mins.

Tim

 

[laminar]

Hey Tim,

Further to what Sam said I wouldn't count on a safety free diver diving to 30m to operate an FHOF solution to raise the diver from depth. That's a pretty stressful thing to do, no matter the skill or ability of the diver who is asked to make the dive. That a dive deep enough to cause complications if the safety diver is freaked out, nervous, scared or afraid of what might happen if he or she doesn't succeed.

Pete

 

[OceanMan]

Quite agree with Laminar. I would definetly not go for 2. 30m twice is a lot in a safety situation.
I would go for 1 : the simpler the better.

 

[turtle]

Hi Tim,

It all sounds really well thought out. I would suggest going with the simplest option - if you have 2 kgs bottom weight, and a hefty buoy to lie over, you can pull up someone very fast hooked on to a 'biner. If you are diving in a group of 3, this is quite efficient. The biggest moment of risk for safety diving seems to be the time it takes to a, realise something is/has gone wrong then b,to act on that. Having relatively complicated safety plans that take an effort to set into motion just increases this risky period.

I don't know of any buoy-based counterweight systems that have ever functioned really satisfactorily enough to be really reliable and effective or worth the effort but i'm sure there must be some way of doing it properly that's not been done yet.

Anyway, those are my uninformed opinions. I'll be really interested to see what you end up doing mate.

Fred

 

[timm]

Yep simplest seems the best, pulling them up seems the way forward, I want to try with some sort of counter weight to see if it helps. I know its not going to pull them up by itself but I reckon an extra 8Kg would ease the pull and would make some difference.

The buoy is on its way so I will be having a play and let you know.(Sam you will probabaly be seeing the results, if thats cool, you can even be victim no.1 if you trust me?)

My only first thought / issue with this solution is the problem with knocking the diver out with the 10kg counter balance weight when it descends. Anyone got any ideas on how to make this a bit safer.

I was thinking of wrapping the weight in something spongy, dont think bubble wrap will help the speedy descnt though.

Tim

 

[BennyB]

Tim the Canadian team at the Worlds had a counterbalance system based on two floats about 6-8 feet apart and attached with a metal pole of some type. I only saw it once when they walked past on the beach but you could probably get in touch with them to get the specifics.

Something as simple as two floats with a broomstick separating them could potentially work though you might want a bit more distance between them to ensure the unconscious diver doesn't receive a rescue clonk on the head on the way back up.

Cheers,
Ben

 

[fcallagy]

Could you pass the line through the pipe with some sort of protection to stop it catching fraying a ninety degree bend on each end pointing downwards so the rope is sliding through it. Bouyed at each end.
Regards Feargus.

 

[timm]

Yeah I remember seeing them walking it along the beach.

I think it might have even had the rope descending down the middle of the pole between the 2 buoys. A very nice set up. But I am trying to keep equipement to a minimum for travelling, 1 buoy 1 rope, they had a load of stuff.

Maybe some sort of 1m or so bar that sits ontop of the float and just give that extra 50cm seperation between lines, hmmmm... would that be enough.

 

[AltSaint]

Shame it's not practical to have 60 metres of lightweight high pressure hose, otherwise you could inject compressed air from the surface down into a liftbag on the plate.

Alun G had a lift method of sorts that he used at Dorothea, but I don't think he posts here any more. Steve Millard knows how it all worked, so it might be worth contacting him ( his email is on some of the team posts ).

 

[AltSaint]

Something slightly more sensible than my first suggestion goes back to your option 1. It means you must have a freediver confident in doing deepwater rescues, to 33 metres ( and who doesn't get involved in the rope pulling! ). When setting everything up, once you have let out 32 metres of rope, you attach something like a climbing ascender to the rope ( to stop the rope moving past the float shackle in the reverse direction ).

If you have to deploy your 10Kg counterweight, then the counterweight shouldn't be able to make contact with the victim, assuming he is dangling down from the plate.

The safety diver should be able to descend at the same rate as the descending counterweight, and if for any reason the victim is further up the line, then move either the weights or the victim.

It's not completely ideal, but then neither is any counterweight system.

 

[tecdave]

Alun's system was very effective in getting the diver to the surface but was a pain to lift the weight to reset it.(hopefully it doesn't need to be reset!) we used a 2m metal bar with 2 large buoys on the end, 2 pulleys on the end of the bar and a sailing rope clutch set on the middle of the bar. The rope ran through the pulleys and the rope clutch and the weight was held to the buoy with a quick release shackle. if it needed to be deployed, you opened the clutch and pulled the shackle toggle. this sent the 20kg down 2m away from the diver coming up. The pulleys reduced friction and increased speed you then use the clutch to stop the rope when the diver nears the surface. Hope you can follow this!!!!!

I will try and dig a pic of it out and post later.

Dave

 

[timm]

Dave a pic would be great if you can find. Although it might not be an option for travelling, weight allowance and 2m metal pole should never be used in the same sentence. But would be great for some UK diving so if you can find please post.

Mark I see where your coming from I think, but wouldnt the climbing ascender get in the way of the lanyard when diving, or did I get confused....

On the same subject concept though, if the divers are comforteable to 35m, then why doesnt the counter weight operator dive with the counter weight down to 30m they will then make sure the weight doesnt hit as they meet the diver(we can still add some padding to the weight), meanwhile the safety diver has resurfaced and started hauling rope. Counter weight rider can safety rescue the diver or surface and pull rope depending on them.

 

[laminar]

I had an idea for a simple and effective safety system based on a single buoy idea last year but never had the time to test it out. Perhaps it might be a solution:

The concept is that you have a wheel or drum with a circumference of one metre with a crank handle on each side. The rope spools around the drum and the drum is fixed just above the water with buoys (more like boat bumpers) on either side. I envision a thin light aluminum frame to hold it all together. It wouldn't very large at all, no larger than a large buoy. In fact, you could also use an inner tube. The drum itself could be hollow as much as possible so that it is easy to turn. No more than 2-3 kg of bottom weight would be used. It's not for competition, just for training.

Anyway, clutches or carabiners could be used to stop and release the rope. But the concept would be simple. One (or in a real emergency, two) attendants could turn the crank(s) to lift the line. Given the circumference of 1m, the line would likely be able to be lifted at more than 1 m/s. You could choose to make the drum have a larger circumference.

An additional safety protocol is to decide on a timing for the dive (ie. the freediver's expected dive time +10 seconds) and then start pulling up the line at 1 m/s. Then you are sure that if a retrieval is necessary, the freediver won't sink deeper before getting pulled up. The line could be reeled in on every single dive. It would be some work (although I'm sure you could figure out some mechanical advantage with the crank) and it would be best to have a dedicated attendant and safety freediver to make it safer.

I'm sorry I don't have a drawing of it. I'll try to get one up.

Pete

 

[Jon]

I know that others have fancier systems, but here's some shots of the one I put together.

I separate the two floats, and the weights, with a 10' long piece of PVC piping. This ensures that when the counter balance weight drops it is about 10' away from the diver on the way up.

I use rock climbing pulley blocks to run the rope through to lessen the friction. These split apart and make it very easy to put the rope in once I have the system set up.

I use standard lanyards, there are other threads on here to show you how to make them, that get clipped onto the down line. I am using something 30-40 pounds of ballast on the counter balance. If you wanted you could start out with you smaller amount of weight and then add in a second float ball that could suspend another 10-20 kg off of to make it a faster ascent from greater depth. I think that I saw a picture that showed Kirk doing this now. This would allow more lead in the water, broken up into smaller parcels, so it's easier to deal with.

Once you have deployed the system the hard part is retrieving the ballast. Using an "ascender" for climbing and a lift bag/pony bottle set up would allow a dive to swim down, fill the bag, and ride it to the surface. Since the drama is already over with there is no urgency to this task and you could repeat it as many times as needed from much shallower depths- so as not to strain the divers. Of course this means investing in a pony bottle and getting air fills.

I don't have a sailing clutch on my system, which would be GREAT to have, but use a couple of cleats to tie things off to when I bring it back up. The only time I use mine is when I have a bunch of divers around- so there are always enough people to share the work with when it comes to retrieval of the ballast.

IF I had the chance to do more depth training, with a smaller group of divers, I would just buy myself a pony bottle and lift bag to take the work out of it- and get all of those free lift bag rides back to the surface to play around with.

I know that others have more thought out systems, but at least you can see some pictures of how I did mine.

Jon

 

[apneaboy]

Hi Timm. We stopped using the counterbalance system over a couple of years ago but i have it in my possession and enough buoys and ropes for you to have a go to at least rule it out. It worked but it was enough of a pain for it not to be practical and that is without transporting it abroad, which i assume you are going to do with it as you wouldnt need it in salt free?

A 10kg weight would not be enough to lift a negatively buoyant diver and also for another diver to ride it on the way down i'm sure. Taking out enough weight to do the job would be like transporting, well ... erm Scuba kit. :head Any weight you take out also will drop the amount of buoyancy the surface float can hold, so bigger surface float (s) needed. You would need a permanent base i think for that method.

Also i can rule out the 'FHOF from 30 metres idea' as last year we were playing with a variable system that left the weight at about 27 - 30 metres and we were using the FHOF to lift it back up afterwards to save some work. All we had to do is go down, attach a clip to a loop and fire the cylinder but they are really fiddly as Sam said to say the least, they are also very slow to fill. Again i have two so you can try if you want. Once fired they would only leave the diver (if they started at 60 metres) at 30 metres. Not the surface, (unless you had a lot of counterbalance weight aswell). Most the FHOF systems ive seen only have about 25 - 30 kg of lift so are not rapid on the way up and would leave 30 metres of dangling line to dodge for the rescue freediver on the way up. The FHOF's are not like riding a sled the are really slow especially if the incident you have has the diver with no air in their lungs. You would also need a method of attaching it that is reliable, quick and fool proof. Plus you need to fill the cylinder. If you use an emergency cylinder (about 0.8 litres??) it would need to be filled every day before you set out from a Scuba cylinder (incase they have leaked in the night or have been used as there is no way of testing the pressure in them, just turning them on a bit and hearing them hiss might mean full, or might mean 20 bar, it sounds just the same !!!!!!). If you used a 3 litre pony they are big and bulky and you would have to swim it down.

Add to that some stress ...

FHOF's are a great safety back up for scubies to use on deep dives, or i suppose if the diver b/o'd in front of you and you had one in your pocket handy, not practical in my experience for freedivers in this particular situation.

The option we use is to have two buoys on the surface attached together by a metal rod. The line is measured at intervals of 1 metre and we simply put a loop in the line at the right point and attach it to a karibiner which means that you have a line attached to the surface that is practically impossible to snap. The spare line is fed onto a reel but that is not rquired only useful. We use a 1 kg weight but it is fresh water and no movement. The reason two buoys (apart from extra buoyancy) is better is that the diver just lies between the two on the metal rod with a snorkel in and its very effective and very quick to lift a diver just lifting the rope hand over hand and we have tested it many times and are happy with it. We know what times our dives are to almost the second and give a big tug on the bottom so can tell when things are not quite right early on. We have also bought an echo sounder too, so we can see where the problem is. This is not something we have used to its potential yet but when summer comes and we are diving deep again we will give it a proper go. We have a platform made for the summer so once we have that platform the counterbalance may be worth using again.

If you want to come up and see us you are more than welcome, i have sent you my phone number in a pm. But bring yer thermals, its grim up North.

By the way when you said the weight will be 'sitting in the buoy' do i take it to mean you are using one of those cloth bags with a car innertube in it and zipped up like the ones used in Egypt? If you are make sure you think carefully about what would happen if the attachment point snapped as they are only stitched. I have one and i am trying to think of a way to make it more secure before i use it. If your not just ignore me

Steve

 

[timm]

Jon thanks for the pics, makes a huge difference seeing something, but still might be a bit too much equipement for travells.

Steve, how you doing good to hear from you. Would be great to come and see you guys and the counter I was thinking of dropping you an email at some point to see if it possible to come up to dotty. Once I have sorted when it would be poss I wil drop you a line, have got a little road trip idea in my head which my pass you guys if poss.

Ta for the info means I can discard half the options, So the FHOF is definately out, and riding the 10kg weight also, it would be more of a drag the weight down. And a double buoy system is out due to travelling.

I am still thinking of trying the 1 or 2 kg and 10kg counter balance just to see if takes alot of the effort out of dragging someone up, if anyone can answer there questions it would help

How much would a diver roughly weigh the line down at 60m? Forget salt or fresh etc, just a rough idea anyone.

Steve have you guys, or anyone, timed pulling up from 10, 20, 30m just with 1kg or 2kg and a diver at the bottom, how long?

If it no too much difference it might be easier without the counter. Will have a go myself and let you know anyway.

Yes the same cloth bag things from egypt. Got the buoy yesturday and had the same thoughts as you about the attachment point. To get around it I am thinking of adding some rope running across the point, it will run horizontal across the bag and the up and tie round the tyre inner tube at 2 points 180 deg from each other. Reckon this would double up with the attachment point and I would trust it more.

Tim

 

[apneaboy]

I have done a 40 metre lift with a diver, don’t remember how long it took or exact weight but in terms of a physical effort it was reasonably easy. The diver was still with full lungs and still had a weight belt on. Sam Still remembers pulling Alun up from 50 metres in 50 seconds on a practice session and it was getting more difficult by then. In real life your under water safety diver would be on his way down to assist by dropping the victims lead and swimming the diver up too.

Having a stable platform is everything though, if you fell off the buoy all the line sinks and it becomes a mess. It is hard then to know which bit of the line is the bit to pull so a second person on the surface can sort out the spare rope at the same time you are pulling up. I think using just one of those buoys is potentially a problem as it is not easy to pull a diver up and maintain your balance sitting on top. We cant fall off between the buoys. I think four people are ideal. One diving, one timing on the surface and feeling the rope for pulls to see if there is a problem and tells the safety divers around if they have turned etc (they then become the rope puller). One person is breathing up ready to dive to assist underwater. A second person who is either second safety diver or surface support depending on the scenario. If the incident was ever serious it would also leave someone to go for help and still two to help the casualty.

Maybe two buoys are not out of the question as they are quite light and pack small. The picture of Jon’s is good to work from, maybe you could have shorter points between the buoys so transporting short plastic poles is easy and you would have a more solid base to work from.

Sam has also done an 80 metre training lift in the Red Sea with a single buoy by attaching a loop under the buoy for his foot, then he lay upside down under water and pulled hand over hand. It is good for someone with a good breath hold and doesn’t mind a bit of lactic. It is quicker because pulling up is easier as you are in a better position.

Another important point about our system is the way that we dive, small incremental increases in depth, never dive right on our limits, consolidate at every depth (with increases no greater than one metre), we pull back for cold weather, pull back after breaks in diving and dont ‘ride ears’. Basically we are very conservative so that the safety system we have never needs to be used. We talk to each other candidly if we think someone is ‘close’. The risks are always there and the system isn’t as ideal as counterbalance, scubies with FHOF’s, loads of safety free divers there so we minimise the problems by diving extra cautious, thats our choice.

 

[Jon]

I should mention that my PVC pipe breaks down into two separate pieces- so it stows in my car for travel without a problem.

One modification that I am making to the system for this year is that the buoy that supports the counter balance weight has been replaced with a dive kayak. This will give it a lot more buoyancy to support a heavier weight and also allow for extra storage of fins, water bottles, cameras and even a complete scuba rig if I wanted to.

The pole will attach right in the center of the dive kayak and I will be able to paddle the whole thing out into deeper water- in the past I either swam it or pulled it with my dive scooter. Another extra safety feature by using the kayak I don't have to worry about one of the floats breaking. I am not worried about the stitching come out of the bottom, I had mine specially stitched for me by Global Manufacturing, but the zippers on the top are not always the strongest and one of my floats now needs to have the inner tube tied into the cover to keep it in place. Replacing the whole buoy with the kayak seemed like the best thing to do.


I will keep the other float on the diver line so as not to have anything too large, or solid, for a diver to run into upon surfacing.

I'd be interested in seeing some pictures of this system that runs a hose from the surface down to a lift bag at the bottom- seems to have potential to me if you can keep the supply hose small enough.

Jon