The Big Thumb

Thumbs Up!

Hand signals are extremely important to a new diver, and I recall using all of my brain power (which is massive) to retain the hand gestures my diving instructor demonstrated on my initial try dive. I got the usual instruction; the OK signal, the wobbly hand, the pointing at something I was unhappy about, and the ultimate of dive signals –‘the big thumb.’

If I give you the thumbs up” my diving instructor began, “that means we surface; immediately.” 

At the time, I imagined if I ever saw the 'thumbs up' I would belt to the surface like a cruise missile; I had no intention of EVER being left behind alone.

With a little further tuition I learned that 'the big thumb’ really just signalled the dive was over; and was to be followed by a slow, controlled ascent including the safety stop. I was also informed 'the big thumb’ was non-negotiable; once it’s delivered, it’s time to go.

One of my initial outings to the sea involved Instructor Man, and another student, as I continued my PADI Open Water course.

My buddy and I were on our knees, 10m deep, in the local Lough performing regulator removal and recovery.

After inhaling my second mouthful of sea water, Instructor Man decided it was time to go; before I reduced the water level of Strangford Lough any further. Instructor Man gave the two of us a very distinct ‘thumb’ each.

I did the very new diver response thing; nodded my head, caught myself on, returned the thumb, provided an OK sign, and eventually finned to the surface.

As I broke the watery threshold, I scanned around to find I was alone. As per instructed, I inflated my BCD, to within an inch of its life, and waited… and waited.

Just as ‘the fear’ was starting to kick in, my instructor and buddy finally decided to join me; thank Christ.

At our debrief it transpired my buddy had neglected to follow the specific instruction related to 'the big thumb.’ Instructor Man was less than happy and re-established our hand signals, stressing the importance of, not only doing everything he said, but also to follow the ‘end dive’ signal without hesitation.

That really stuck with me; even to this day.

Wifebuddy and I use the big thumb on every dive; at the conclusion of another fabulous underwater adventure. That said, on our last dive it was featured long before the planned time. This of course resulted in a premature finale; but, all things considered it was the correct thing to do.

The plan was a simple shore dive on The Inner Lees; a shallow wreck dive in Strangford Lough. We have visited the site a number of times and know the wreck very well.

The Inner Lees
courtesy DV Diving

Jeep parked up and buddy checks done, we waded through the long shallow area, finally reaching a depth where we could allow the big wings to take the weight off the twin 7’s.

Kerri wading in

It was agreed Wifebuddy would lead the dive as she was more familiar with the site. I also brought along my camera with strobe attached, in the vain hope of capturing something in focus and not engulfed in darkness.

That was perhaps a little enthusiastic, correct lighting and focus still eludes me.

Good viz in the shallows

The dive is best conducted on low tide as that is when the wreck breaches the surface; the 80m swim out is a little easier to navigate that way. Our last dive however, featured a particularly high tide and the wreck was completely submerged, so we had to guesstimate.

Wifebuddy picked a bearing; we descended a few metres and began to swim towards the suspected wreck location. The Inner Lees is one of the few sites in the Lough that sports quite good visibility, well, in comparison to most sites over here, but on that particular day it was uncharacteristically poor.

Viz began to deteriorate as we progressed

Between current and visibility problems we opted for a bit of a surface swim. I hate surface swimming, but it was a necessary evil. Finally, I banged a fin on something solid; I stuck my face in the water and confirmed we were on the wreck.

Regrouping, Wifebuddy and I decided to descend down the side of the hull, keeping close together; as this wasn't our usual practice and it would take a moment or two on the sea bed to orientate ourselves.

On the bottom visibility was atrocious, and personally, I had absolutely no clue where abouts on the wreck we were. Kerri signalled she knew what was going on and led the dive.

After 10 minutes I started to become increasingly unhappy about the whole thing. The dive was much darker than usual, heavy sediment was swirling around, and I was having difficulty keeping track of Kerri as I duly followed her about.

I’m not usually bothered by bad vis, but I couldn’t orientate myself properly; I didn’t recognise anything.

An overcast day added to a dark dive

We reached the rear of the wreck where she had broken up, or so I thought. It looked vaguely familiar, but in the grim visibility I couldn’t be sure. Certain parts seemed to be in the right place, but beams, pipes and various other metal struts started to make me believe otherwise.

Then the fear really kicked in as I pondered the question – am I inside the fucking thing?

My breathing accelerated and I grabbed Kerri’s arm, attempting signals about an overhead environment. Kerri signalled that everything was OK and to continue on.

The Inner Lees is pretty well broken up, but there are areas where it would be difficult to surface once entered. I became increasingly convinced we’d inadvertently penetrated the wreck.

This is my ultimate fear when scuba diving.

I managed to keep my breathing at an acceptable level and attempted to rationalise the situation. I signalled Kerri to stop. It seemed unlikely we’d ventured into the ship as we had simply been following the hull, but I couldn’t be sure. Even if Wifebuddy knew where we going; i didn't.

I’d had enough. I was getting stressed and not enjoying the dive anyway. It was time to go. I checked my gauge; we’d only been in for 28 mins and had no decompression obligations.

I gave Wifebuddy the big thumb. Kerri responded with an OK and we began our ascent.

I watched my depth gauge as the numbers decreased. I strained my eyes in the hope of sunlight, but nothing; the visibility had eaten my world. I fully expected to hit my head on a steel ceiling as my gauge fell below 1m and I held my arm up to protect myself from the pending ‘clunk.’

Thankfully I broke the surface without the aid of a blow torch and all was well. I have to admit I breathed a sigh of relief and was totally ready to get the fuck out of the sea and go home.

On our debrief Kerri explained she knew our location on the wreck exactly, but was about to terminate the dive just before I did. We had been experiencing some nasty weather of late, and Wifebuddy was convinced the wreck had either shifted, or broken up further.

She had concluded that either way it was unsafe to continue as we simply couldn’t see what had changed.

Safe on dry land

Once a diver receives a big thumb, the dive is over; that is all there is to it. If appropriate, ascend; if not, make your way back to the exit point. There is nothing underwater worth dying for, and it will certainly be there on the next dive.

I am really looking forward to returning to the Inner Lees soon to investigate the possible changes to the site, but if at any point I’m not happy the same rule will always apply.

A familiar, shallow, simple dive site can be changed completely by poor visibility, sea conditions or a different approach.

The big thumb means it’s over; no matter what.

Big thumb = fins hung up for the day
Safe diving folks.


  1. I had to thumb my second last advanced open water dive a few months back. Was on my first deep dive, about 25M's down when my new Oceanic Atom 3.0 Watch started throwing unreadable characters on the display. Sharing a computer for depth/bottom time etc is one thing, but of course, being the tech head I am, I went for the option with wireless air pressure, so while I knew how much air I had about 20 seconds before the watch crapped out, I only had a vague idea how much air I would be sucking through and therefor how much I had left.

    I was buddied with the DM and quickly made a few made up combinations of hand signals (pointed to watch, unsure hand wave, signal for how much air and a big shrug of the shoulders). He seemed to get the point and I showed him the watch quickly. We were only a few M's in front of the other buddy pair, so thumbed the dive to them and the DM just pointed to me, pointed at his eyes (ie: watch me) and we started a nice easy ascent. Did our safety stop and got to the surface nice and safe.

    While there's not a hand signal for every circumstance, or you may not know any of them, if you've got the basics down, using combinations and a bit of common sense, it's surprisingly easy to convey a fair bit of information underwater. And as you mentioned, once someone thumbs it, that's it!

  2. Forgot to mention.... watch was sent back and quickly replaced by the manufacturer without any hassles at all.

    Will be investing in a secondary/hosed gauge shortly!

  3. Seems like a perfectly reasonable situation to thumb the dive; no doubt it was the correct decision.

    As you say, sharing a depth gauge is one thing, but losing your ability to confirm your air supply is a bit dangerous!

    Sorry to hear your computer failed, but glad you got it sorted out.

    Yup, Wifebuddy and I have complete underwater conversations some dives!! :D

  4. And for those un-signable bits of conversation like:''I think i just saw a big white, why don't we go debrief at the pub?'', there is the indispensable notebook.
    (or slate, but the notebook is so much cooler and you can keep those precious bits of abyssal wisdom or works of art you use it for!)

    My respects to wifebuddy dude, and may you 2 have wonderful holidays!


  5. Yeah, wetnotes is always useful, although it's amazing how easily Wifebuddy and I can communicate underwater!

    Cheers Jean-Louis; i hope you get some good trips in yourself!


Thanks for commenting, I appreciate it!

Safe diving buddy.