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safety issues / FHOF

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Semi aquatic monkey
Jan 16, 2003
Hi, creatures of the blue.

we are diving in switzerland, no saltwater, often bloody cold, viz under 1m. So we always use a bodyline/lanyard, to not loose the line. In theory in case of emergency it would also be possible to pull up the line and hence the bodyline including the missing diver. I personally doubt, that it would be possible, because there s the ground weight plus the divers weight to be pulled up. Not an easy thing if your in the water ! So it would be very interesting to use a system like presented in the article on safety in Cyprus : the FHOF (Freediver Hook On and Forget) strange name, but basically it s a ballon, attached to the diver, with small bottle of gas. Pull the gas, balloon fills up, diver goes upwards.

Has anyone of you made experiences with this system ? Good ones/ negative ones ? Anyone knows who produces it ? Or someone built one ? What happens with the diver in the last meters of an ascent with a fully filled balloon (guess its very very fast) ? thank you for your posts !
we use FHOF all the time in saltFree
each of our scuba diver safety divers carries one and has practiced using it.
You can buy them from the freediver web shop
www.freediver.co.uk or from any dive shop.
They are basically a scuba diver SMB with attached cylinder. They are made by BUDDY (called SMBCi) or Aquatec. You then need to attach a big carabiner to it and a wrist strap with D ring to each freediver

They work like magic. If you attach it to a freediver at 15m in our lake they come out of the water to the waist... it takes a few seconds to take off but once it goes you rocket to the top, much faster than finning. Several of us have had a go - its fun! but don't do it if you have sticky ears as it is quite fast.

We have also tested them in HMS Dolphin from 30m and plan to test them deeper with saltFree

Here are a couple of pictures


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this is me on the FHOF


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I've been F'd up (fancy terminology huh?) from 25m by SaltFree safety before, and it was HELLA fun! :)

The rate of ascent was very quick, and the last meters go by in a blur so if you pack your lungs very full it's best to let some air out before you normally do because you'll hit the surface before you know it!

The SaltFree scheme is to attach the FHOF to a wrist D-ring (as in the picture. I believe the Canadian scheme is to attach a lift bag to the line under the lanyard, but I've never seen it in action.

Peter S
hi again.

this is why i LOVE this forum; within 12hrs you get good information, and even more than I asked !!

The DRUMS-idea seems to me a very good idea, basically what we need over here. Thanks to Fattah/Scott for their golden angel !

As well the FHOF seems to be very effective, thanks for your answers samdive and longfins.

It seems though the FHOF is used with scuba-safety divers. We normally just have freedivers as safety in training. So here comes my idea: Every diver takes a FHOF around his waist, the trigger of the gas cylinder attached to the weightbelt, so that if the diver or his rescuer drops the weightbelt, the FHOF start to inflate and pulls you up. What do you think about that ??

Greetz, Dan WISR
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Quick question - if you're doing maximum depth dives recreationally (ie not in comp with a bunch of SCUBA divers), and you're diving deeper than your buddy can, how do you activate his FHOF if he gets nto problems?
Good question. The saltFree always have a safety SCUBA diver with an FHOF positioned at the depth of the deepest freediver, for just this reason. Of course, you can limit depths so that you are always shallow enough for your buddy to be able to rescue you. If you want to go for your maximum, and that's deeper than your buddy can do, then you have some risks to weigh up.
loopy, that s really a problem; all of our divers are within the same 10m max depth. except for one ( national recod holder with -56m) so none of us could ever get him up (unfortunately he is not only the deepest, but also the heaviest of us ;-). So this situation speaks strongly for the Fattah DRUMS system.

The whole thining leaes me to the next question: When I did Skydiving we used a system on the parachute, that measures the Airpressure (altitude) and time, and calculates speed. So you can tell the system: if at 500m above ground i still have a speed of 50m/s pull the trigger, to open the parachute. This is for that the parachute opens even if you black out. Now for the technicians out there: wouldnt it be possible to create a system like that ? Saying: longer than 3mins under 30meter (or whatever numbers you take) and the system inflates the FHOF ??

Another alternative system of retrieving freedivers is using a counterweight system on the line. The freediver is hooked to the weighed line via a lanyard, and the line is hooked to a larger set of weight at the surface. Any trouble and the surface person release that weight, bringing the entire line with the diver attached to the surface.

Here's a schematic of the system used by martin stepanek:


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the French system is also good if you don't have scuba divers to FHOF you.
Everyone wears a lanyard. the line is lowered from the boat with a bottom plate at your estimated max depth. As soon as the guy on the boat feels you turn he starts to pull the line up slowly. The idea is that you normally get up before the line, but if you don't for some reason, at least you are on the way up somehow. Bit like drums really...you just need someone strong on the boat.

FHOF opens and fills by opening a tap like those on a scuba cylinder valve so would be hard for the freediver to open it himself in an emergency (not to mention bulky to carry on every dive). I guess you could fit it with some kind of quick release cylinder like the small ones on life jackets but then you would only be able to use it once - and it may not have enough air to get you to the top quick enough. Our FHOFs have 0.2l cylinders.


What was the diameter of the PVC pipe used in Martin's system?

Do oyu know what size line, and blocks, they were using?

I want to make one for Ted and I to use.

The air storage that is reusable by filling from a scuba tank or compressor is great on SMBCi, but I wish it would inflate by just the pull of a string or lever rather than the turn knob.
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I believe their PVC piping is 3-4" diameter, has drilled holes for rope loops to go through to attach the buoy and rope blocks, the way they do 'soft attachment' of blocks onto spars and such. The PVC piping only serves as a standoff and doesn't bear any tension from buoy and weighed block (the rope loops do). The mushroom anchor is ~18 lbs, enough to do constant ballast; more weight for free immersion.

The rope blocks they have are just some sailing blocks Doug P has from back in the day. I personally plan to get snatch blocks so I don't have to thread the rope. Diameter: I don't know. Their rope is a custom-braided rope that's longer than 100m.

NOTE: The safety release for the big weight is not clearly shown on the schematic. The release (snap shackle) is actually 10m underwater. The logic is that the safety diver at 10m, if suspicious that the freediver is in trouble, needs to only travel 10 feet across to pull the release instead of coming all the way back to the surface to do so.

Hope that helps,

Peter S.
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Let's look at the various freediving safety set ups which exist:

Class 1: Setups which involve SCUBA divers
1. Classic scuba setup (scuba divers must toss the body from one diver to the next to get him back up)
2. Scuba w/FHOF (must have scuba divers all the way until the bottom)
3. Scuba w/Counterbalance system (divers communicate to the surface operator when the counterbalance must be triggered -- does not require a diver at the complete bottom)
4. Scuba w/FHOF AND Counterbalance (does not require a diver at the bottom)
5. Scuba w/ line lift bag (line lift bag = french method of attaching a lift bag to the line bringing up the bottom plate and the diver)
6. Scuba w/ FHOF and line lift bag
7. Scuba w/ FHOF, line lift bag and counterbalance
8. Scube w/ line lift bag and counterbalance

Class 2: Setups which involve no scuba divers but require a boat
1. Boat based manual DRUMS
2. Boat based electric DRUMS (sebastien murat's method)

Class 3: Setups which involve no scuba and no boat
1. Blind counterbalance [using ballast] (Doug Peterson / Martin Stepanek method)
2. Blind counterbalance type approach, but using manpower to pull up the line
3. Manual in-the-water DRUMS (FSS GoldenAngel)
4. Electric in-the-water DRUMS (no one has tried it yet)
5. Very experienced, deep safety freediver (still cannot cover more than about 25-30m of depth)

The system which offers the fastest recover of the diver is Class 2, method 2, 'Boat based electric DRUMS.' However, it is not practical for most divers.

Obviously, class 3 is of most interest to the average diver. In my next post I will examine the pros/cons of each of class 3.

Eric Fattah
BC, Canada
Thanks Longfins,

I can understand how that would be nice for Kirk when he's traveling, but I have the added luxery of only being able to drive to my dive sites.;)

Because of this, I was thinking of using one of my dive kayaks as the combination float/ seperator bar instead of the bouys and PVC pipe. I could attach a block to each end of hte kayak and that would easily give me more that 10' of distance between the ropes. This would also make it easier for us to swim it out from shore with the weights.

If I kept the blocks on climbing webbing I could easily move it from place to place. I think this might work out really well when I get to actually get use a boat- put one strap on either side of her beam and run the rope underneath. This could make the system even more portable. I know that this might not work for everyone, but we just don't have the high flow currents in the Great Lakes like others do in the ocean.

I was wondering if anyone has tried the metal safety "8's", used in rock climbing, instead of a block? They would be more rugged and a whole lot less expensive. I am just not sure about how much added friction they would cause- assuming you just ran the rope through the large hole and not all the way around the "8" like you would if you were belaying someone.

If that would work I could see being able to put one of these together fairly cheap. The cheaper it is the more people that could make them- which then leads to safer diving for a whole lot more divers who want to go deeper.

Comments? Suggestions?


I am in the process of buying a dive kayak myself :) and will be rigging it up as you described - slings over the bow and stern and use the entire kayak as float / separator. My buddy Aaron (Octo) is a sailor and climber par excellence, so I'm sure he'll come up with a kick-ass rigging scheme for the kayak-counterbalance.

Good point regarding the '8' and climbing hardware in general. Sailing would require ropes to run through blocks as opposed to a metal hoop because in sailing the ropes run through their mechanical advantage points continuously. In climbing the ropes though carabiners or '8's mostly just hang there and would run through only intermittantly when you belay someone, say. Therefore I would conclude that a block's primary function is to reduce rope wear. In a counterbalance you're not running the rope continuously, plus the load is much less than in climbing / sailing. So as long as the rope isn't badly damaged a block isn't wholely necessary. The added friction from rope/8 contact is significant I think, but probably won't reduce the ascent terminal velocity that much if you use enough counterbalance weight.

Blocks are kind of spendy, but there are some snatch blocks at West Marine made of delrin that's 20-35$. Locking carabiners are less than 20$ each, same with 8's. Climbing pulleys look attractive too. So there's some room to experiment there.

Cool! :cool:

Peter S.
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Hi All,

Peter, thanks for posting my drawing. I'll toss in a few specifics for those interested:

PVC is a nominal 4" ID by 10 feet

The blocks are, as Peter said, just some seriously huge blocks I had from my years sailing. You can use anything, even snatch blocks as Peters wants to use (Great idea, Peter!). Any block that will take the load and the line diameter.

The line is one we had braided by Miami Cordage and it is 5/8" x about 130m. Optimists aren't we?<G>

The Buoys are the large, 21" dia Taylor Tuffend style buoys. Just one of them will support the entire rig in the event of the failure of a bouy. We would prefer the 27" ones with over 300lbs of buoyancy but they take up a LOT of room and were very expensive.

The blocks are attached, as Peter said, to the bouys directly with 5/8" line that passes (twice) through the PVC so that the PVC is NOT structural, it is there only for separation.

Not mentioned previously: The "release line" has snap shackles at BOTH ends so that the rig can be deployes from the surface OR from the 10m safety position.

As with anything we do, we do not claim that this is the "be all, end all" freediving safety rig. This one works for us in conditions we have to deal with here. Period. We do not think that monofilliment would do here because of the risk of entanglement in the sea state and current we face even on a calm day. This rig works for us quite well even in high seas. We have used it in as high as six foot waves in the Gulfstream where we train. If we were in calm water I assure you that we would probably be using something different. Your mileage may vary...

This rig, because of the weights involved, should be deployed from a boat (unless you had reallllly deep water just off a calm beach) and it is heavy and a bit cumbersome but three of us deploy it in a few minutes and it takes only a few minutes to retrieve if you have not dropped the counterballast. Then, unless you want the ultimate upper body workout, a lift bag, climbing ascender, and a tank come in REAL handy! If we ever did deploy it in an actual emergency, the entire rig is then considered disposable, if necessary, to get a diver back to shore.

We will happily listen to improvement suggetions or even a better rig design so put on your thinking caps and remember to please let us know when you come up with something better!

By the way,

I love all the ideas about using a kayak for the seperator! If you don't have a boat this is great for taking the rig out, perfect seperation and *IF* you had quick disconnects on the blocks you coulds abandon just the counter-ballast part and race to shore.

We use climbing ascenders to retrieve the rig but I do not know about the climbing 8s.. might work fine but our goal, from the beginning, was the fastest ascent rate possible so the friction might be an issue.. and if you add more weight then you are adding other issues. For the slight increase in cost, I think that I would stick with blocks but if someone tries it with 8s please let us know how it works!


Thanks for all the info and welcome to DeeperBlue!

Regarding the "ultimate upper body workout" of hauling up the counterbalance weight from depth, I plan on something different from lift bag and scuba tank since putting all that weight and stuff into a single kayak, plus the given diving location (Monastery Beach) will make the situation ungainly enough.

An alternative to hauling up the counterbalance weight is to attach a block/pulley at the ascender, loop a line through it, fix one end to the surface, and pull up with the other to gain a 2:1 mechanical advantage. You will be hauling half the weight, but for twice the distance.

For example, if the descent line weight is 20lbs and the counterbalance weight is 60lbs, deployed to 150ft. You use a haul-up line of 100ft long, looped through the pulley which then halves the length of the haul-up line, FI down 50ft to attach the pulley & ascender, and return to the surface to pull the rope. The effectdve hauling force needed is (60 - 20) / 2 = 20 lbs. Repeat 3 times. So in the end you will have pulled 450ft of rope with 20lbs force to haul up 150ft and 60lbs of counterweight (300ft + 150ft of descent line which is now back at the bottom.)

Or if the descent line (20lbs) is kept at the surface, then you will be hauling a 30lbs load for 300ft. The total work in this example, no matter how you cut it, is 9000 ft-lbs.

In a real emergency I would disconnect and abandon the entire rig, of course. But in normal operations we would want to practice deploying the counterbalance weight now and again to check the system and keep our skill level up. So I think being able to haul up the counterbalance weight on a regular basis would help with this.

This method is better with divers in lesser depths obviously. I don't think Martin or you or Tony will want to haul an equivalent of 200m+ of rope even if the weight is halved! You guys will have drifted to Bermuda by then!

Peter S.
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