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Discussion Starter · #1 ·
Hi All,

I'm not new to the concept of tidal flows and that sort of thing, but underwater currents have often confused me. I was hoping the big YD brain can clear something up for me...

I know of, and have hear of, dive sites where people say that there are "dangerous drop-offs" and "rip currents". Perhaps other sorts of currents too? Am I right in thinking, therefore, that there are places in the UK where you can be happily diving at 20m, with perfect buoyancy, but suddenly get sucked down to 50m or more by a current?

There's a few welsh dive sites in chris holden's book which sound a bit like the above, and the thought of it scares the crap out of me, so I'd be interested to know.... especially if it's happened to someone here.

Thanks All

Adam
 

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All hail the mighty ZOM
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Falls of Lora. Some guys from our club went to dive it and you have no control over where you end up. Risks include burst lungs, burst eardrums and of course DCI. And to add to the fun, you can also get hammered into a depression on the bottom from where you can't get out. I have heard of one bloke who had to launch a DSMB and lock off the reel to yank him out and another who had to ditch a weightbelt.

Another classic "oh deary me is that a beep I hear" are the Scapa blockships. Fire a blob on the Tabarka and watch the line reel off like the fishing rods in Jaws. Then follow the line up and enjoy the ride which varies between 15m and 5m with no control from you. Wheeeeeee!
 

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Discussion Starter · #3 ·
Falls of Lora. Some guys from our club went to dive it and you have no control over where you end up. Risks include burst lungs, burst eardrums and of course DCI. And to add to the fun, you can also get hammered into a depression on the bottom from where you can't get out. I have heard of one bloke who had to launch a DSMB and lock off the reel to yank him out and another who had to ditch a weightbelt.

Another classic "oh deary me is that a beep I hear" are the Scapa blockships. Fire a blob on the Tabarka and watch the line reel off like the fishing rods in Jaws. Then follow the line up and enjoy the ride which varies between 15m and 5m with no control from you. Wheeeeeee!
Niiiiiiiice

I reckon it might be the falls of lora which I heard about first, back during my club diver training... I certainly remember something about potentially not being able to get back up.

Is it a fairly common pattern of currents? I don't suppose there's any way of identifying them over and above trial and error?
 

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All hail the mighty ZOM
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Niiiiiiiice

I reckon it might be the falls of lora which I heard about first, back during my club diver training... I certainly remember something about potentially not being able to get back up.

Is it a fairly common pattern of currents? I don't suppose there's any way of identifying them over and above trial and error?
That and not diving them mid-tide on springs. That also helps.

Other sites that spring to mind- Corryvechan whirlpool (you get sucked down to 130m if you don't dive it right).

In general, local knowledge, charts, a set of tide tables and bloody good planning is what gets you diving safely. The BSAC Advanced Diver course teaches all of this :)

Oooo another one- Whirl Rocks off the Farnes. Have done that one and cos we planned it properly, there wasn't a jot of current on it. Get it wrong, and it's like diving in a washing machine.
 

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Jesus don't want me for a sunbeam
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They chucked a dummy in to the Corryvechan with an Aladin Pro strapped to it. Then wound it in. The dummy had "quite alot" of missed stops... :)
It had also been dragged horrendously deep, lost limbs, was full of gravel and generally had the crap kicked out of it. I seem to remember someone who had dived there saying when your exhaust bubbles start going downwards then it is time to leave :D The Corryvreckan is impressive when you see it from a boat, Grey Dog's Race as well (same sort of area).

There are a few sites round Scotland with down currents on them. The wall at Lochaline can have some quite strong downward flows, the Kintyre allegedly does (I've never noticed but people have reported it).
 

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There are quite a few interesting rides around the channel islands. Large tidal ranges funnelling between islands tend to get a bit quick. There is a popular drift off the back of sark that regularly hits 6knots so i am told. That is quite fast.

Similarly when these fast tides hit areas of shallower or deeper water suddenly, the current trys to follows the topography and the eddies etc create all sorts of effects.

Fortunately, in most places tides are pretty predictable, as is bottom topography so you should be able to figure out where this stuff happens.

Charts and local knowledge will also go a long way to helping you out
 

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I've been in a downcurrent abroad and I really, really didn't like it! Everything goes mental, our bubbles came back to join us in a massive cloud, then left in what appeared to be a downwards direction, the computer told me I was at 30m and then at the surface (i wasn't), buddy jacket at full inflation had no affect. I'm actually starting to sweat and shake just remembering it! It eventually just gently let us go, unlike 3 Americans who were shot out like spinning missiles in a jet of bubbles. When we got back on the boat, the dive guides were crying and insisted on hugging us (ick) and forcing cake down our throats (yay)

And you forgot to mention that the 'ride' from the Tabarka includes big jagged walls of rock that rush up behind you...
 

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I am a person NOT a number
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That and not diving them mid-tide on springs. That also helps.

Other sites that spring to mind- Corryvechan whirlpool (you get sucked down to 130m if you don't dive it right).

In general, local knowledge, charts, a set of tide tables and bloody good planning is what gets you diving safely. The BSAC Advanced Diver course teaches all of this :)

Oooo another one- Whirl Rocks off the Farnes. Have done that one and cos we planned it properly, there wasn't a jot of current on it. Get it wrong, and it's like diving in a washing machine.
When we were at Sound of Mull couple weeks back it was on Neaps tides and the guys all had eventful dives on the Falls of Lora. Alan the skipper said he prefers to put divers in on an ebb tide but due to dive times it was on a flow tide, or the other way round. I wonder if that made a difference to our experience diving the same place last October?
 

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I get thrown to the surface from 14M somewhere off Anglesey one time, can't remember where. The same happened to the two guys I was with, there was a rip tearing through a small channel, myself on one side of the rip and one guy on the other when we hit the surface, we had to watch the water and when the time looked right shout at him to fin like f*** to get to the side of the rip we were on....This was at night, we couldn't risk getting split on the surface, it was quite a rush but nothing compared to some of the stuff above....
 

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Our club regulary dived off Anglesey at a place near Llanfwrog and a couple miles out there is a place they call the skaries or skerries (sp) and yes several divers have been caught out in similar circumstances, thankfully this occured in day time so possible not so scarey.
 

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There are quite a few interesting rides around the channel islands. Large tidal ranges funnelling between islands tend to get a bit quick. There is a popular drift off the back of sark that regularly hits 6knots so i am told. That is quite fast.

Similarly when these fast tides hit areas of shallower or deeper water suddenly, the current trys to follows the topography and the eddies etc create all sorts of effects.

Fortunately, in most places tides are pretty predictable, as is bottom topography so you should be able to figure out where this stuff happens.

Charts and local knowledge will also go a long way to helping you out
I can vouch for the swift tides....
We dived a pinnacle called Noir Pute off the back of Sark - beautiful dive - on slack. However, if you miss slack (as we did), it becomes an amazing drift. We were swept off the pinnacle and very fast over a scoured flat seabed.
This seemed like a good idea until I realised the SMB was on the seabed behind us (one of the old BSAC washing line/polystyrene floats that were virtually unsinkable). We decided to surface - to no boat or land...
It took a while for the boat to find us - we travelled 5 miles in less than an hour - cracking dive!
 

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I've only ever done a couple of dives in a strongish current. I think I was once told that in a current the flow of water will take you round or over big boulders. I seem to remember it being an article about a river in New Zealand where you get thrown along at quite a pace. This seems to be the case when I've dived but I've never asked anyone for sure. So I generally just go with the flow, quite often moving backwards. Should I be worried about being smashed into big rocks?
 

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I got caught in a fast down current off Woodhouse Reef, Red Sea, along with about 9 other divers.

Whipped us from about 10m down to 30m in seconds, I remember those who were below me sending up such streams of bubbles I couldn't see the reef wall through them. It levelled off horizontally at 30m and then gave us all a fantastic high speed ride around the dark side of the reef.

It ended as abruptly as hitting a wall - suddenly those in front slowed back to normal fin speed and I thought I was going to be flung into them when it dropped me too and I was simply finning slowly along behind them.

Once we relaxed and had levelled off we all had a great ride.
 

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Another classic "oh deary me is that a beep I hear" are the Scapa blockships. Fire a blob on the Tabarka and watch the line reel off like the fishing rods in Jaws. Then follow the line up and enjoy the ride which varies between 15m and 5m with no control from you. Wheeeeeee!
love the tabarka though :D -

also corryveckian pinnacle (SP?) - look it up - bubbles can end up going DOWN :)
EDIT:OOPS! read thread before posting Mike!!

just remembered a dive I did in Tenerife - after Alibabas cave (43m ish) we came up a wall and did deco in a whirl pool that sent us round and round and round at a steady 6m lol. I was dizzy by the end of it.

Also remember a diving south coast of Ireland and doing a mental drift but can't remember name -

Also also - fairly mad weird currents on the fastnet lighthouse around the gulleys around it. It is rumoured there are tunnels under it - can anyone confirm that - I have been told about them but never saw them when I dived it
 

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There's various places down south you can dive, either at the 'right time' or the wrong that are ...er....interesting.
One place that comes to mind is the 50m pit off St Albans ledge - you dont want to dive that on an ebbtide I dont reckon.
The other is the Mixon Hole. Only 35m to the bottom, but again, you dont want to get it wrong. I'm diving there on Sunday, I'll let you know how it goes.
 

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Done the tabarka which is one of my top dives ever it's quit funny being inside the wreck and looking out to see fish finning like fuk in the current not quite so funny when you Got to surface though!

Another wreck in the flow think it was the gobenador doris we started off at the prop went down the wreck which is upside down then went for a drift fir a while, kept stopping, changing direction and eventually ended up back at the prop!

As for the falls of lora get it right and it's superb get it wrong and your smashed to bits!


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