Portland
25-27th July 2003

Trip Report by David Martin

Divers:

Last year, John, Iain and I had regularly headed down to Portland, for a day or a weekend, in order to complete our Trimix Course. We'd booked boats and sometimes even accommodation at Breakwater, so knew the set-up well. It had however been a while since we'd been able to do any decent diving, so we were anxious to get a weekend in before heading to Ireland, our main summer trip. John and I had a free weekend a fortnight before the Ireland trip - Breakwater was thus the obvious choice. Since the two trips were only two weeks apart, I was able to consolidate some of the logistics of our weekend with those of the larger trip. We arranged to stay with Rowan, a friend of ours who's been on a couple of CUUEG's summer trips, at his flat in Southampton. Rowan was also diving off the same boats, to complete his Trimix course with Izzy.

I left Oundle late in the afternoon, collected John and the kit in Cambridge, and arrived at Rowan's for a late meal. We then brought various bits of dive kit in, in order to fix things. John and I also worked out our plans and bailouts for both days' dives. In addition to the usual personal faff, I also rigged the emergency drop bottle.

Shortly after Rowan and John had gone to bed I realised that I'd left both the bolt and connector from my P-valve in the wash-bag meaning that both ends were currently fully open. I wasn't about to trust knots or gaffa tape to plug the hole, given that we were planning dives with approximately 40 minutes of decompression stops and very much doubted that replacement parts would be available at 7am on Saturday. I made a quick decision, packed everything that I'd need for diving, left a note on the kitchen table, and then headed back to Oundle. Rowan would take John to Portland, and I'd meet them all there with most of the kit. Finally, before leaving, I phoned my parents, to explain why someone would be in the house for 5 minutes at 3:30am!

In 2002, we'd decided that driving from the Cambridgeshire to the Portland in the middle of the night was generally to be avoided. Let's just say that driving from Oundle (N.E. Northamptonshire) to Cambridge to Southampton to Oundle to Portland through the night is definitely to be avoided! I arrived at Portland harbour at 0715 for a boat at 0800 – leaving just about enough time for us all to assemble our kit and get on the boat (we were about five minutes late).

Saturday 26th July - The P555

Depth: 45m
Bottom Time: 25 min - plan *
Mix: 21/35 and 50%
Deco - plan: 1@24, 5@21 (50%) 1@18, 1@15, 2@12, 4@9, 10@6, 5 to surface
Refs:
    A. Divernet report
    B. Trimix Course, P555 Dive
    C. Portland trip, July 2004, P555 Dive

* The deco schedule was planned for 25min, but we reduced this to 22min to add conservatism to compensate for my lack of sleep – the actual Dive Time was less than 20min.

The P555 is British submarine that was sunk to create a sonar target for naval practices. She sits in a cradle above the seabed, and due to the controlled method of sinking, is nicely intact. Iain and I had dived the P555 for our qualifying Trimix dive last summer; but John had been unable to dive due to illness.

On the descent my primary light bulb blew, and the backup refused to turn on. John therefore passed me his backup for the dive. I can remember precious little about the bottom phase of the dive. We got to the sub, and swam around it; I seem to remember spending most of the time around the conning tower. I got myself caught in monofilament line, but John dealt with it quickly. John called the dive before 20 min; I think we'd swum all the way around the wreck, but the real reason was probably that he was concerned about my inability to concentrate. Sadly the drama wasn't over. At 21m John duly switched to 50%. However, when I switched my deco gas had a horrible taste and worse smell, so after several minutes trying to work out what the problem was, I gave up, went back to backgas informed John that I we'd be doing the backgas bailout deco schedule.

I had enough back gas to complete the bailout stops, but due to poor planning/execution, I wouldn't have been able to complete the accelerated stops for the plan on John's 50%. This was in part due to a greater time spent at 21m than planned, whilst I tried to resolve the problems, and also because both John and I were breathing at a higher rate than we'd used for planning (we'd used the figures from the end of last summer, but were not yet that "dived-up").

The length of the backgas bailout schedule would require almost all of my backgas, and would require John to revert back to his own backgas once he'd finished the accelerated stops. Since we couldn't guarantee to cope with a 2nd failure ourselves, the agreed procedure was that we'd shoot the yellow "send gas" DSMB. I deployed my yellow at the 9m stop. However, the drop bottle didn't arrive. At the 6m stop, John therefore shot his yellow too. We then got the drop bottle, shortly followed by Izzy – who'd finished his dive, and had become worried that we had a serious problem! Izzy passed me his stage, which I used for part of the remaining stops. Since the dive plan we were using for the bailout was longer and deeper than our actual dive we did the 20/100 rather than 20/80 backgas profile, then came up.

As a result of the dive we developed a new method for deploying a drop bottle, this would be further refined with experience.

John and I only had one dive, whilst Rowan had a second in the afternoon. John & therefore spent a fair bit of time, but uncharacteristically not too much money in the local dive shops. After Rowan's second dive, and with all the cylinders at Breakwater for fills we headed back to Southampton. It was raining heavily, so the planned BBQ turned into a trip to the fish & chip shop. In the evening, we met up with some of Southampton University SAC. Sadly we weren't quite able to get into the swing of their drinking games: Rowan had to drive, I was virtually falling asleep (having not been to bed for 40 hours) and whereas they were diving the Countess of Erne, the three of us had rather more demanding a dives the next day.

Sunday 27th July - The Salsette

Depth: 48m *
Bottom Time: 20 min
Mix: 21/35 and 50%
Deco - plan: 1@24, 5@21 (50%), 1@18, 1@15, 2@12, 4@9, 7@6, 5 to surface
Refs:
    A. Divernet Wreck Tour 11
    B. Trimix Course, Salsette Dive
    C. Portland Tech Trip, June 2004, Salsette Dive

* A plan depth of 45m is more appropriate, and has been used for subsequent dives.

The Salsette is arguably the best wreck dive in Britain. Our previous dive couldn't have been more different from such a claim, but after today's dive we'd could see why people think it's the best, and would certainly support a top five ranking.

When we arrived on site, I was suffering from seasickness, and after a couple of attempts to kit-up, decided not to dive. I'd agreed with John and Izzy, that in the event that I wasn't up to diving, that John would join Izzy and his students. However, it appears that Izzy didn't hear me tell him that we'd adopted this backup plan, and jumped in without John. By the time John reached got to the shotline, Izzy et al. had disappeared out of sight.

Budgie suggested to John that he could join two others just about to go, but their gasses (air, 32% and 80%) and kit (lump hammers and crowbars) suggested there was an irreconcilable difference of opinions, and incompatible decompression profiles. Given the choices of a dive that might have to be cut short; or, no dive; it seemed sensible to at least get in the water to see how I felt. Due to the tides, and the delay in the start, we agreed a reduced run time, with a 20min bottom time.

We descended near the stern, and dropped onto the deck (the wreck lies on the port side), then worked our way forwards. Much of the wooden deck planking is intact, although isolated planks or sections are missing, allowing a look behind them. There were a great many gaps and holes, a significant number of which are probably worth exploring – there are two decks of cabins within the hull. The visibility was probably about 10m, and a significant amount of sunlight penetrated as far as the seabed. All around us were shoaling fish, mainly Pollack; in fact, the visibility was mainly determined by when your line of vision was interrupted by fish! The short bottom time was rapidly used up, and we were forced to ascend well before we got to the bows. This is certainly a wreck that we want to come back to, and with a longer bottom time!