TDI Adv Nitrox & Deco Procedures – Part 3

DAY 4

So, having passed out TDI Advanced Nitrox exam we only had 1 dive remaining to complete the course. Now, this left Kerri and I in a bit of a pickle. We still had 3 days of holiday left and the plan had originally been to just do some diving with our new twinsets and enjoy the wonderful wrecks Malta has to offer. However, we were still unable to do decompression diving so all this gas we had with us wasn’t really of much use, so to speak. The next step on the ladder was TDI Decompression Procedures – sounds even more impressive no? We had considered doing this alongside the nitrox course but we didn’t want to task load ourselves and risk wrecking the holiday so decided against it.

TDI Decompression Procedures

Now, however, everything had changed. We had the tech diving bug. We decided it would be a complete waste if we didn’t do it and not very cost effective. We also really enjoyed the course so far, David was a great instructor and we felt really at ease with him. That was our rationale anyway. We sort of asked David if he felt we were capable of doing another course and he explained we shouldn’t have any problems, but we would need to speak to the boss Agnes and see what the arrangement would be with money and his time and stuff. So, wife-buddy and I strolled into Maltaqua and subsequently signed up for the deco course there and then. Agnes did us a great deal and some of our dives from the nitrox course could be credited towards the deco procedures. This was great news, we only had 3 more dives to do and a lot more classroom work. We got our manuals, then set off for another days diving.

We arrived at our familiar Cirkewwa dive site and continued with our new ritual of dive brief, kitting up, START drills and then the bubble check once in the water. Today we would be heading out to the P29, a Condor Class Patrol Boat scuttled in August 2007. The blue water swim was slightly longer than the previous efforts, but I was getting used to them now, my buoyancy control was improving and I wasn’t freaking out anymore. A visible improvement, I liked that and I patted myself on the back accordingly for the days achievement.

Kerri enjoying a swim through

Once on the wreck we did a circuit of the deck and visited the prop at 37.9m. This was my deepest dive ever, and buried my wrist in the sandy bottom to get the deepest reading I could in order to annoy David later, I just knew he was a little competitive. In reflection this was actually poor form by me. I had already calculated my MOD (Maximim operating depth) for the mix I had in my cylinders and it was 37m. I had increased my PO2 level – doh! Luckily my dive had been planned with a max PO2 level of 1.4, so I had a little to play with as the safety margin is 1.6. This was not very tech at all and although it wasn’t a critical mistake, I had a plan and didn’t dive it. Mental slapping for that one.

We left the wreck after a few excellent swim throughs and headed back over the reef to depth of about 14m. David gave us the signal that we needed to simulate a decompression stop and shoot our smbs. We fired up our blobs and hung on our lines and simulated an obligatory decompression stop. This was grand, the depth was easy for maintaining buoyancy and Kerri and I looked dead good just hanging horizontal in the water. David then took our spools from us and we conducted a successful valve drill. We were really on the money today. We did a further OOG drill and the dive was concluded.

Once on land we had our debrief and I owned up to diving too deep for my mix. Bad tech diver. We learn from our mistakes and I had realised the importance of monitoring depth at all times. We sat on the truck and chatted for about 45mins to allow some off gassing and then it was back for a dip in Suzie’s Pool. This is a shallow area near the shore where we would be doing some skills with our new “stage” bottles.

I have to admit, diving with a twinset was pretty cool, but once the 7l aluminium stage bottle went on I really felt the part. Bloody well looked it too. I clipped off my stage cylinder to my harness and stood up. Ok, this was getting heavy now. Mental note – go to gym when home and work on legs. I was definitely reaching my physical max for carrying kit around. Kerri was doing a great job and appeared to be suffering no ill effects from the extra kilos. I wish I’d picked a set of girly twin 10s. Ahem. Cautiously we wobbled down to the entry point and managed to step into the pool. Once in the water all the weight disappeared. This stuff really was designed for in water use.

We were then subject to so many skills I can hardly remember them. The task loading was getting greater and this really felt like we were getting into some serious learning. First up was a 30m tired diver tow on the surface wearing our new stages. I grabbed wife-buddy by the valve and started finning. Hard work I can tell you; wearing my own twin 12’s and a 7l stage, towing a diver wearing twin 10’s and a 7l stage. I was highly appreciative of wife buddy’s small frame. Kerri was up next and managed to tow me along the surface, accompanied by a few expletives questioning just how far you had to be towed and in the real world I’d be on my own and she’d send a helicopter upon reaching shore. Descending to about 8m we repeated the process underwater, much easier.

Kerri looking dead tech diverish

Stage handling was next. We had to unclip our stages and stow them, go for a bit of a swim and then go back and collect them. Easier said than done. Wife-buddy didn’t appear to have any problems with this at all, I have to admit I struggled a bit finding my lower bolt snap and then attaching it to my wing, probably my "man hands" and dry gloves interfering. Yes, that was it for sure, wife-buddy has those tiny wee hands and fingerless gloves and therefore more dexterity. Either way she was doing way better than me. Nevertheless I finally got reattached and adjusted my buoyancy accordingly when dropping and retrieving the supposed neutrally buoyant cylinder.

Next up in the David torture session was regulator out swimming. I don’t have a problem taking my reg out but I knew Kerri wasn’t really impressed and always felt the urge to continue breathing, even when removed. You really only get to do that the once. So, regs were extracted and we both bolted on our 15m reg-out swim. Tough, but doable. Having said that, David made us repeat the exercise another until he was satisfied, which was on the 3rd go. Cheers for that. So with my lungs on the verge of exploding we were then signalled to gas switch. Dutifully we deployed our stage regulator, turned on the valve and began breathing our 49% nitrox mix for the first time. I have to admit, I was a little underwhelmed. It was cool, what with a “stage bottle” and all, but in reality the reg was lower performance than mine, uncomfortable and the gas tasted just like any other. However, I was now on a deco stop and to hover at 6m for I can’t remember how many minutes, but it all went according to plan. With our simulated deco obligation fulfilled we had to stow our stage regs and make our way to the exit point.

It was soon clear that stages and I just did not agree. I just couldn’t seem to get control of it at all. All I had to do was tuck the hose down the 2 bungee cords around the cylinder. But no. Instead I chased the dam thing around the reef. I really looked the tech diver now; struggling, breathing heavily, beginning to sweat and verbally cursing the thing to hell and back. What was going on? Finally I managed to secure the hose and I regained my composure and sorted myself out. I looked around for the first time in what had seemed a lifetime and I was nowhere near where I had started the drill. I was met by a black mask staring straight at me with a disbelieving look of “what the hell are you doing mate?” In my frenzy I had drifted into the middle of some rebreather divers doing a decompression stop. Well, all illusions of being the awesome tech diver were obliterated then and there, what a twat. I signalled my apologies and sleeked off to catch up with David and Kerri. Kerri had her stage already secured, handed it off and was conducting a weight check with 50bar. I had to do the same and purged my primary until I reached 50bar. It was clear I was too heavy as I plummeted to the sea bed when I dumped air from my wing. The dive was well and truly over.

I just about managed the giant step onto the shore fully kitted. The extra cylinder just seemed to make all the difference. It was nice and calm which led me into a false sense of security, my concentration lapsed and somehow I pulled my arm the wrong way on the hand rail and a burning sensation shot up my should. Arghhhh!!! That really hurt. I had lost all feeling in my arm and struggled up the hill to the truck. Finally I got to the truck and got my kit off. I was shattered and my arm hurt.

Homework!

We returned to the classroom for some decompression theory and I nursed my arm in an attempt to get some feeling back. Class was concluded and we headed to The Peppermill for some quality steak and chips. I managed to get a grip on my less than perfect performance, wandered back to the apartment, did my homework and finally got some sleep. Still another 3 days….