Our Trimix Holiday…

40-70 metre visibility, but very demanding conditions and 70 metres deep!

The trip up.

August found Simon and I in a heavily loaded car heading up to Ayr in Scotland. The car was groaning under the weight of our twinsets, 2 stages each, multiple torches and plenty of other bits and bobs.
We were on our way to meet the メLoyal Watcherモ, a liveaboard which catered for people wanting trimix holidays. We had booked this trip over a year ago, and were both very excited to be on our way! Our plan was to get on the boat in Ayr, then cross the Irish Sea to Donegal, where we were to be diving wrecks in 40-70 metres in gin-clear visibility for the week.

The boat and the crossing

We were astounded at the size of the メLoyalWatcherモ. It is a big, very seaworthy boat. It has been bought by a couple called Darren and Linda, who have refitted the boat. They have done a fantastic job! They are both very capable skippers, and Linda also does all the cooking during the week. There was also Richard ミ the メdeck-bitchモ, a very pleasant young guy who helped with everything. He had the massive task of filling loads of twinsets with trimix, and lots of stages with various nitrox mixes every evening. He often filled until late at night! He has an easier time of it when the group is mostly rebreather divers but with 9 of us on open circuit the fills took a long time.

The Loyal Watcher (Click for a full size version

Everyone on, we went to our bunks to get some sleep, still not sure if we were even going to cross the Irish Sea that night, as the weather was decidedly dodgy. However, Darren made the decision to go at about midnight, and what a night that was!! There was a Force 9 blowing outside, and it was ROUGH. A few people nearly lost gear through the scuppers but luckily all was saved just in time! A few people also spent some time on the upper deck talking to their maker!

Our first day’s diving was blown out, but I don’t think anyone minded too much as there were still a few green faces recovering from the journey across! We moored up in the calm of Loch Swilly, on the north-west coast of Ireland. Darren ferried us across to the local pub in the ship’s dinghy to enjoy some proper Irish Guiness that night. We were a group of 11 divers; some of us knew each other already, but everyone got on really well.

The diving

Monday brought cloudy skies and rolling seas, and 11 divers eager to dive the メLaurenticモ. Darren came down to brief us, with the words メlook at the sea state, if you are not happy to climb the ladder in this, don’t get in!モ. We all decided that we WOULD get in, and get out again!

Jumping in

This is a massive wreck in about 40 metres. There was a terrible surge at depth which didn’t really help with the seasickness in general! However, the visibility was awesome, more than 25 metres; there were hundreds of massive fish in shoals as Ireland has a ban on fishing wrecks; and the wreck itself was amazing.

There were also loads of crabs, crayfish and lobsters everywhere as it is also illegal to take sea life whilst diving in Ireland.

We especially enjoyed seeing the fairly intact bow, with the anchor in place and mooring bollards with chains still around them.

We did the dive with twin 12’s on our backs, and two 7-litre stage bottles each, containing 40% and 80% nitrox for decompression.

It was quite a challenge climbing the boat’s ladder with all this gear; normally you could hand off your stages, but in seas this rough there was not enough time. A few people (myself included) were seasick again on getting back on board!!


The other wrecks we dived were all in the 60 ミ 70 metre range. We used trimix in our twin-12’s consisting of 18% oxygen and 45% helium. The helium is used to lessen the narcotic effect of nitrogen so that you have a clear head when at these depths. We also carried two seven-litre cylinders each, one containing 40% oxygen (known as a travel gas), and the other containing 80% oxygen (known as a decompression gas). These were used in getting to and from the wreck, as well as for the long decompression times we had to run! To give you some idea of the dive times, we mostly planned a 25 minute bottom time (time on the wreck), which often meant about an hour of decompression. Most of our dives were about 90 minutes in length.

The decompression stops were done by ascending up the shotline again and going onto the lazy shot. Once all the divers were on the line it was cut loose from the main shot and we could decompress as a group. Most divers would also send up their own DSMB (delayed surface marker buoy) so that they could hang in comfort at the required depths for their stops. If everyone stayed on the lazy shot it would become very overcrowded!

Luckily the weather improved day by day, and we got to do all the big dives we had gone there for. The メEmpire Heritageモ is a wreck that was carrying Sherman tanks (loads and loads of them!) and is a great dive in about 63 metres. The メJusticiaモ is an awesome wreck in about 67-70 metres, with the biggest portholes I have ever seen. It has an awesome bow, a bit like the メTitanicモ, but unfortunately our shot-line was just too far from the bow and none of made it there!

Our favourite wreck of the week was the battleship HMS Audacious. We did two dives on this wreck, mainly around the stern section. There were still intact propellers. The stern section was quite broken up so it was fantastic to rummage around here. You could also get into the magazine and marvel at the huge shells she was carrying for her guns.
The visibility was fantastic, mostly about 25 metres, so you could often get an impression of the size of the wreck whilst descending down the shotline. Quite often you could do the dive without the need for a torch at 60 metres!


This was a fantastic trip. It IS deep, and you need to build up to do these dives, but it is worth every second of every minute; every penny of every pound spent!.

It is very demanding diving, both mentally and physically, but the rewards are great!

I WILL be going back!.