This is another part of our special articles about Thecnical Diving.
Read also [Part 1] [Part 2][Part 3][Part 4.1][Part 4.2][Part 5]
After our last course the wrecks of a.o. Malta and Croatia have been our playground, building experience and confidence until the dives worked like clockwork, letting us fully enjoy the beauty of the places we dived. Wreck’s like the Um el Faroud, HMS Hellespont, HMS St Angelo, SS Vis and SS Kalliopi…if you don’t know these and ever get the chance, go dive. Every single one of them is worth multiple dives. If you need information on excellent diving centres that make your diving great, just contact us.
But…an increase in bottom time in the range we were diving and – to be honest – the longing of the deeper wrecks eventually made us decide to go the final mile. We spend many an evening discussing with whom we would like to take the Tech-2 class and – more important – were we would like to dive.
Decision was made and…
Finally you have to grab all your diving gear together for a final check and see if it fits the bag and meets the luggage restrictions.
Malta, here we come…6 course days ahead and some additional days for fun diving – hopefully in the Tech-2 range (75m) – the beautiful Maltese wrecks.
No delays, no last minute stress, no lost luggage…all omen seem in our favour when we land and get ourselves installed in St Julian’s. We drop our diving gear at the dive centre and feel immediately at home at TechWise. All is already set and prepared for the course. Promising.
Off to enjoy the sun and check for a place to eat. St Julian offers plenty of good places for a drink and a munch, so choosing is probably the most difficult part.
DAY 1
The Next day we meet up with our instructor and after a brief course overview get to work on the academics; a recap on advanced mixed gas diving including planning, gas requirements and basic strategies and general overview of the various risks involved with decompression diving.
The larger part of the afternoon is spend on the house reef mainly focussing on our current platform, skills & drills. A solid platform is the most valuable asset you have in the water column; when the proverbial [beep] hits the fan, it is the backbone of any solution to a problem. Without? Chaos. And it is amazing just how many things can go wrong, malfunction or get lost when you spend 3 hours in the water laying line 😉
During the comprehensive debriefing some pointers to bear in mind and work on during the coming days were noted, but all in all not too bad for a kick-off day.
[note to self: slow is smooth, smooth is fast]
DAY 2
After a nice cup of coffee, academics continue mainly focussing on stage handling; multiple bottom and deco stages as well as an hypoxic protocol as breathing gasses for the deeper dives no longer are breathable on the surface due to the low oxygen content (15%)
We hit the water to put it all to practise. Every descent from now on will start with the hypoxic protocol, no matter the breathing gas or target depth. Through the shallows we moved to a nice playground on the house reef for clipping…clipping…clipping…and some more clipping, rotating stages in every possible way…and…not a single one was dropped.
However, as time in the water column is limited, being able to complete a rotation is say under 2-3 minutes is mandatory, so we clipped some more. Fingertips, you ask? We haven’t kept count on how many bolt snaps were clipped, but surely if you were to wear gloves, they will be ripped after some 4 hours in the water.
Finally, a nice mind crusher scenario involving an OOG breathing from the stage with Houdini-loss of back gas and…ehm…oops…sorry, no spoilers for those who still have the intention to do the course themselves. Not the smoothest of performances we have ever done, but we managed to get it all sorted.
And to top it off you find your team member floating in the column, playing unconscious. We spend a couple of rounds taking this diver safely to the surface
[note so self…never skip breakfast on a course day]
DAY 3
Academics, of course. Today’s sessions was all about ascent rates, advanced breathing gas strategies and contingency planning. Quite confronting to realise the shear amount of gas you need to take with you to safely dive the deeper wrecks. As it would take a good 18 minutes to reach the next available gas source at 21m from a 70m dive in case of an emergency, minimum gas requirements are extensive and the margins of error in an OOG event are very limited. Did we mention that platform already?
We can now almost hear the question mark on the 18minutes. Without too much detail (we promised no spoilers, right?), for a Tech-2 dive we would typically calculate 1 minute to resolve simple problems, then the ascent starts at a rate of 9m/min to 75% of our depth (another 2 minutes to 51m), we change ascent rate to 3m/min to 50% of our depth (another 6 min to 33m) and change the rate one more time to 3m/2min (another 8 min to 21m) finally allowing typically 1 minute for the gas switch. In total 1+2+6+8+1=18min. Multiply this time required by 2 divers and the divers gas consumption rate and you know the amount of your Minimum Gas for the dive.
By the way…changing ascent rates in the column is easier said than done, so…of to Cirkewwa.
That is after our standard, thorough checking of the breathing gasses filled, correct marking and labelling of all tanks, right? Right.
Upon arrival kitting up and running our pre-dive checks once more, one of the manifolds proved not to be open. Say what? Yes, it happened. So we spend some time in the sun while the set was taken for a proper re-fill. Needless to say, we felt rather stupid…
The remainder of the afternoon? Up and down, up and down…with all sorts of failures on stuff we did check, unexplainable prolonged-OOG events and even missing stuff when you need it, knowing it was there a minute ago…funny that…
[note to self: never, ever forget to triple-check the manifold…]
DAY 4
On the menu: first course being advanced decompression theory. Both physics and physiology on blood flow, tissue saturation and gas transport in the body really come to life when explained by someone with extensive academic knowledge and experience in the subjects.
Second course is all about decompression history and modelling development over the past decades, highlighting the benefits and shortcomings of each of the models developed.
Final course places all in perspective in a quest to find a practical approach to decompression. We compare many profiles in even so many models and decide we prefer bubble models to guide us through the deeper part of our ascent to say 21m and dissolved gas models for the shallower part of our ascent. Once more the choice of diving standard gases proves very valuable.
For those who don’t recall, here’s a small reminder. We have chosen to dive with the following standard bottom gases in the various ranges based on an END<30m, working pO2 of max 1,4 and deco pO2 of max 1.6: EAN32 to 30m, Tx 21/35 to 45m, Tx 18/45 to 60m and Tx 15/55 to 75m. Standard deco gasses are EAN50 from 21m and EAN100 from 6m.
Desert: Planning for the 18/45 dive on HMS Stubborn…yes, on the wrecks!
HMS Stubborn
This S-class submarine of the Royal Navy was launched on November 11th 1942 and sunk as an ASDIC target after the war (30.4.1946) at 57m depth.
We plan for a max. 40min bottom time at an estimated average depth of 54m, giving us a planned deco of 60min in total.
Flat sea…nice!
Pre-dive checks, gas switch, jump in, to the shot, drop to bubble check and switch depth, check team an gooooooo…and from 30m already there she was…be-au-ti-ful.
Makes you realise one of the bigger benefits of diving deeper wrecks; less people dive them so the amount of detail is just great! We have plenty time to pay attention to those details and after a good 30min we end up back at the shot line and decide to call the dive, adjusting our deco to the shorter than planned dive time. Although our average depth proves slightly less as well, we keep it as planned, entering a re-planned deco of 40min in total.
When we arrive at our 6m stop we realise weather has changed quite a bit. High roller waves great us and the last stage of the deco is a bit of a challenge. Strangely but fortunately enough hardly any current still.
We manage to get ourselves on board unharmed and brace for a bumpy ride back. Boat captain Jordan proves a Master of the Waves and brings us home safe and sound.
Debriefing with very valuable feed-back on team performance, choices and communication followed and off for diner we went.
[note to self: go dive again and challenge the depth rating of the Go-Pro]
DAY 5
Theory on the breathing gas dynamics, focussing on the influences of oxygen, its tolerances and (CNS)-toxicity including hyperoxia and hypoxia. Finally a good bit on narcosis (from nitrogen, oxygen and co2) is dropped on our plate and munched.
Finally a recap and wrap-up…all set for tomorrow’s exam, except for some dive planning on Schnellboot S31.
She sank after she hit a mine and now lies at approximately 63m atop a white sand seabed. The wreck is broken amidships and the majority of the ship’s dark wood has rotten away. The wreck has a huge amount of interesting items still on it, including 20mm ammunition on the decks, the starboard tube with the torpedo still in it and the propellers in place. We love the Maltese no-take policy for all her wrecks!
One word: WOW! What a nice dive!
So much to see, that when back at the 21m stop the team wasn’t unanimous on the deco profile, hence we took the most conservative one proposed. Debriefing the dive learnt that we could have saved quite a few minutes of coping with the current on the 6m. Also team communication when landing on the wreck could be improved; time spent at depth not “exploring” is valuable as gas is depleting rapidly. Let’s call it valuable experience, shall we?
[note to self: ask Dave for the pictures sneakily taken by a second “no bubbles”-CCR-team diving with us]
DAY 6
Last course day already…time flies when you have fun while on a steep experience curve!
Exam-time – with a cup of coffee…excellent teacher as we remembered almost all the important subjects covered during the academics sessions and passed.
From the yippie-ka-yay feeling we snapped back to reality as HMS Southwold unfortunately proved a no-go for today’s dive.
Re-visiting Schnellboot and get in a solid dive and ditto deco in was easily agreed upon!
And we can tell you that diving it a second time was great fun as we now knew the specific spots we wanted to see in greater detail. And the more fun as the dive went as planned with proper team work and communication, amazingly without a single “event”. Great confidence boost and absolutely not the last dive we hoped to make in this depth range.
But…still one more thing to complete. As if lugging all the equipment for the past days wasn’t some sort of prove of our fitness, off to the local pool for the final swim test. Glad to say, we made it 😉
Then, the closing meeting for a debrief on the team, individual feed-back and pointers for improvement and finally the big moment; would we get the word GO and be able to plan for HMS Southwold and Polynesian in the coming days?
We already learned the wind would have us move to Gozo to scooter-dive the wrecks of Karwela and Cominoland (also highly recommendable dives, by the way), but…would we…
YES!!!
Needless to say we had a fan-tas-tic course week building our team, skills and confidence for the days to come. We did dive Southwold, we did dive Polynesian and… the GoPro just about survived our photo-dive on the Stubborn. But maybe, just maybe these adventures will be told in a future story. If you don’t want to wait, please feel free to contact us, we will be happy to share our stories or answer any questions you may have.
For now, happy & safe diving and who knows…we’ll run into each other someplace or another. Hope to see you at the waterfront and do not forget to like and follow Team Pitch Blue on Facebook
WORDS by Richard Anspach and PICTURES by Mark van Bronswijk
