Logbook Scuba Dive # 140 - SS Courier
| Logbook Scuba Dive # 140 - SS Courier |
| Date: | Entry Time: | Dive Time: | Max. Depth: |
| Sat, 27-Oct-2007 | 11:59:00 | 28 minutes | 41.2 metres |
| Dive Location: | City / Island: | ||
| SS Courier | The Heads, Bass Strait, VIC | ||
| Country: | Dive Master: | ||
| Australia | Bob | ||
| Dive Charter: | Dive Trip: | ||
| Dive Victoria | - | ||
| Buddy/Buddies: | |||
| Heather Bertrand, Peter Chew | |||
| Dive Details: | |||
| Entry: | Boat Name: | ||
| Boat | Nemo | ||
| Start PG: | Entry Time: | Exit Time: | End PG: |
| A | 11:59:00 | 12:27:00 | - |
| Altitude: | Rep. Dive: | Surface Interval: | |
| 0 m | No | - | |
| Max. Depth: | Avg. Depth: | ||
| 41.2 metres | 24.86 m | ||
| Dive Time: | Deco. Dive: | ||
| 28 minutes | Yes | ||
| Conditions: | |||
| Weather: | Air Temp.: | Water Temp.: | |
| Sunny | 20 °C | 14 °C | |
| Water: | Waves: | Current: | |
| Salt | No Waves | Light Current | |
| Visibility: | Horizontal Vis.: | Vertical Vis.: | |
 Bad |
- | - | |
| Equipment: | |||
| Weight: | Dive Suit: | Dive Computer: | |
| 22 kg | Drysuit | Suunto Vytec DS | |
| Equipment used on this dive: | |||
| Apeks ATX100 Regulator | Apeks ATX40 Octopus | Apollo Bio-Fin Pro | Buddy Surface Marker Buoy | DUI Weight & Trim 2 Harness | Faber 15L Steel Cylinder | Mirage A250 Wrist Slate | Northern Diver CNX2-RI Dry Suit | Northern Diver Mini Metal Wreck Reel | Northern Diver Superstretch 2mm Neoprene Gloves | Northern Diver Thermalskin | Oceanic Spinner Pointed Dive Knife | Oceansuits 3mm Hood | OMS Compact Quick Dump Weight Pockets | OMS Dual Bladder, Banded Wing - Rec | OMS IQ Pack BC Harness | Sonar Explorer Blue Silicone Mask | Suunto CB-Two-In-Line Combo Console - 1 | Suunto SK-7 Compass Wrist - 1 | Suunto Vytec DS Dive Computer | Waterborne Safety Strap - Vytec | |||
| Cylinder Set #1 | |||
| Cylinder Type: | Cylinder Size: | Working Pressure: | Supply Type: |
| Steel |  15 litres |
232 bar |  Open Circuit (OC) |
| O2: | He: | Min. PPO2: | Max. PPO2: |
| 48% | 0% | - | 1.4 bar |
 EAN 48 |
MOD: | EAD: | END: |
| 19.1 m | 9.2 m | 19.1 m | |
| Start Pressure: | End Pressure: | Diff. Pressure: | |
| 236 bar | 74 bar | 162 bar | |
| Avg. Depth: | SAC Rate: | ||
| - | - | ||
| Avg. Depth: | SAC Rate: | ||
| 24.86 m | 24.89 litres/min | ||
| Gas Mixture: | |||
| Air Nitrox 48% | |||
| Boat: "Nemo", Bob, Dive Victoria I booked with Dive Victoria for this dive on the SS Courier knowing Heather Bertrand and Peter Chew were going to be aboard for the dive. This was to be my first deep dive and second boat dive in my drysuit. I organised a pony bottle with Peter Fear to give myself a redundant air supply. I headed down to The Scuba Doctor where Peter Fear topped up my 15 litre cylinder. The 5 litre steel Faber pony bottle had EAN 48% with a MOD of 25 metres. The pony had no pressure gauge attached. Heather, Peter and I discussed our dive plan. They were planning to do a longish bottom time and a decompression dive. My dive computer was telling me I could do a no decompression dive of 7 minutes at 42 metres. I was prepared to go slightly into deco depending on my air consumption. So the plan was that I'd leave them and ascend alone. Not a very wise plan. I suggested that if the visibility was okay, I could stay a bit higher than the others and not go all of the way to the bottom. (As it turned out the visibility was very ordinary at about 5 metres max.) Anyway, armed with a not very bright dive plan, I headed off down to Portsea and checked in with Dive Victoria. I geared up and made my way out onto the pier. There was a long wait for the dive boat, but it was a very nice sunny day and I got to chat to some fellow divers. Eventually the boat arrived and everything was transferred aboard and we had a pleasant trip out to the dive site. I managed to get into my kit a lot better, though I still needed help with the neck seal, rear zip and pony bottle. On checking his pony bottle, Peter Chew's gauge was reading zero, so our dive plan was changed to a no decompression dive. (It turned out his pony bottle gauge was at fault.) The three of us entered the water after the other six divers onboard and made our way to the shot line. We started to descend. I had the line in a loop of my thumb and forefinger in my right hand with it slipping through easily. I kept slowing up to match pace with Peter who was alongside to my left just off the shot line. Heather was slightly above us. The visibility was very ordinary. After the equalisation problems I experienced the previous Saturday, I'd prepared better all morning and didn't have any such problems on this dive. After a while I checked my depth and was surprised to find that we were only 10 metres down. I was very conscious that I was having to slow up my descent so as to stay with Peter. As it turned out Peter and Heather were finning away into the current and descending as fast as they could in the conditions. In the end it took us 6 minutes to make our way to the bottom. Thus I arrived on a sandy bottom at 41 metres with my dive computer saying I had 1 minute of no deco time and 160 bar of air on my back! Plus we were on sand, the shot line having been dragged off of the wreck, and we couldn't see the wreck. By the rule of thirds, not taking into account the air in the pony bottle, I was already at my turn around point and should have aborted the dive. But I didn't. Heather followed the drag line in the sand and guided us onto the bow of the wreck. By then I was into deco time and was very conscious that I was using air too fast. I signalled to Heather that I was going to ascend. I couldn't get Peter's attention, and headed off alone trying to make my way back to the shot line. This was a big mistake. I should have started ascending towards the surface straight away. It eventually became obvious to me I had no chance of finding the shot line and I had clocked up additional bottom time and used up even more air. I started to ascend immediately and had to work hard to control my ascent rate. I became very aware that if I didn't sort a few things out I could easily kill myself. So I started to think through the problem. My dive computer was giving me a ceiling of 22 metres for my deep stop and my pony bottle mix was MOD 25 metres. So as I ascended towards the deep stop depth, I opened the valve of the pony bottle and unclipped its regulator so that it was ready to use. As I approached my deep stop depth, struggling to reduce my ascent rate, I spotted two other divers off to the right above me and made my way towards them. They were ascending even faster than me, so I quickly gave up any idea of joining up with them and focused on switching to the pony regulator and doing my deep stop. At this point, I only had 80 bar on my back and what was in the 5 litre pony bottle. Next thing I know I've risen to 15 metres conscious that I need to complete my deep stop with my computer flashing away madly having risen above the ceiling it was recommending. So I try to descend back to my deep stop depth of 22 metres but drop past it to 28 metres. Again I become aware that I'd better sort this stuff out or I'm going to kill myself. I start to ascend again. I go past my deep stop ceiling, but get some control at around 15 metres. My dive computer has now cleared the deep stop obligation and is telling me I have to do 4 minutes at 3 metres. I know I should be shooting my DSMB, but figure there is no way I can handle the additional task loading. I need to stay focused on controlling my ascent. I start to ascend. I realise that there is no way I can tell how much EAN48 I still have in the pony bottle and that based on my air consumption so far, I'd better be ready to switch to the air on my back at any time. So I get my primary regulator into my right hand so as to be ready. I start trying to slow my ascent to do my safety stop at 5 metres, but shoot past to 2 metres, try to descend but end up on the surface, with my dive computer in error. I try to descend back down to 3 to 5 metres without success. The dive boat is way off to my left. There are two divers with SMBs deployed also off to my left and another two off to my right. So I wait as the boat moves in to pick us up. My dive computer is in error, but mostly because I haven't done the recommended safety stop. The settings on my dive computer are very conservative, plus it doesn't know that I've switched to EAN48 whilst at 22 metres some time ago. So I figure that I'm probably going to be okay but that I should take some preventative measures and keep breathing from the pony bottle. Once on board I keep breathing on the 48% Oxygen of the pony bottle and take things very easily and slowly. I eventually get out of my gear, still breathing off of the pony bottle. Eventually everyone else is back onboard and we head back in. Inside the heads the pony bottle runs out and I switch to Heather's 54% Oxygen pony bottle. Back at Portsea Pier I unload and make my way back to the car and get changed. Then it was off the the cafe for lunch and back to The Scuba Doctor in Rye. I'd made some very poor choices with regards to this dive. 1. I wasn't ready to do a deep dive in my drysuit, especially not my deepest dive to date. My buoyancy control in a drysuit wasn't adequate for the task. 2. I had stupidly planned to do a dive where there was every chance I'd have to leave my dive buddies and ascend alone from 40 metres. 3. I took myself into deco time at depth with my air use far too high and stayed too long at the depth. The result was that I became very aware that I could easily kill myself while doing this dive. No-ones fault but my own. I'm still around because I managed to not panic and work through the problems, but it's not an experience I wish to repeat. |
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