Cork Sub Aqua Club

Now that the weather limits open water diving, Cork SAC divers are taken the opportunity to up skill with a nitrox course. Nitrox is air enriched with pure oxygen, also know as enriched air nitrox. Compressed air has been the most common dive gas since scuba diving became mainstream. Air is a gas mixture of 21% oxygen and 79% nitrogen. The nitrogen part might become a cause of concern for the scuba diver. When the diver ascent too fast, the dissolved nitrogen can cause bubbles and this might develop into the decompression sickness, better know as the “bends”.  Furthermore, on deeper dives the increased levels of nitrogen have a narcotic effect on the brain, the severity of the effect depends on the susceptibilty of the individual and the depth (absolute pressure), the individual is diving at.

So it is not supprisingly that navy’s, scientists and the like started to experiment with breathing gas mixes to counteract the disadvantages of conventional air mix as a diving gas. During the seventies, the American scientific agency – NOAA (National Oceanic and Atmospheric Administration) researched extensively the effects of increased levels of oxygen and reduced fraction of nitrogen in breathing gases for scuba divers. And in the early eighties a new diving gas was promoted, called nitrox. This gas is also know as “Enriched Air Nitrox (EAN)” or “Safe Air” or “ The Devils Gas “ by the skeptics at the time. The higher percentage of oxygen in the mix will limit the diver to a maximum dive depth. The benefits of nitrox, compared to air, are a direct result from the lower percentage of nitrogen in the mix. The main advantages are the reduced risk of decompression sickness, less apres-dive fatigue, and longer dive times.

On Saturday 12 November, Cork SAC instructor Helen Buckley organised the nitrox diver course for region South, on behalf of the Irish Underwater Council. Three different dive clubs, namely NMCI, Blackwater Fermoy and Cork Sub Aqua, did put forward a total of 5 candidates.  The theoretical part covers topics such as dive physics and physiology. Furthermore the future nitrox divers were thought how to analyse gas mixes and calculate CNS% – uptake. After a full day of lectures, Cork SAC candidates Vanessa Casey and Jessie Castle passed the theory exam with flying colours. What remains for both candidates is the qualifying dive on 10 December,next. Once both diver are certified, they will be able to dive nitrox mixes up to 40%, with a ppO2 limit of 1.4bar.

On the weekend of 5 and 6 November, three Cork SAC members attended the advanced nitrox course in the Clubhouse of Blackwater SAC in Fermoy. The lectures, on Saturday, focussed on compulsary decompression, i.e extra required dive equipment, dive techniques and emergency and contingency plans. The practical part took place in Portroe quarry in Co.Tpperary. As this is a technical diving course the expected level of the skills is very high. All participants practiced drills such as mask swapping, swapping stage cylinders, reel work with blacked-out masks and deployment of the suface marker buoy underwater. Next the candidates need a minimum score of 80% to pass the theory exam, before completing the qualifying 40 meter dive with up to 10 minutes of mandatory decompression. Cork SAC candidates for the Advanced Nitrox course were Donncha Cronin and Stephen McDevitt. And Joost Vanmuysen attended the weekend as part of his Advanced Nitrox Instructor course.

The Aud lies at about 31 meters depth near the Cork Buoy at the entrance to Cork Harbour. She was a covert 1916 world war one German sponsored gun-running enterprise to the Irish Volunteers but she was discovered by the British navy. She was scuttled by her crew when she was being escorted to Cork. The remains of the wreck are very much scattered, and the boiler is pretty much the only intact part. A very entertaining dive, the bullets are everywhere, and look like gravel on the sea bed. Keep an eye out for congers and ling, but the anglers seem to know this place well so we didn’t see many fish.

It was a relatively early 8:30 AM start from Oysterhaven to make the one hour time window after low tide that is the best time to dive this wreck. The sea was flat calm on the way there but the forecast force 3-4 southwest winds had made it a little more choppy on the way back. The earliest down had less disturbed silt to deal with but even Laura and Eileen, the last two to dive, described the visilbility as fairly good. I would say 10 meters at the beginning but it was more disturbed near the boiler.
Thanks to Claire for coxing and for the chocolate and coconut chunks. Thanks to the O’Connell family for the loan of their boat.

Aud Bullets

Declan C diving the Aud

More Aud Bullets

Originally uploaded by riordan_david.

Paul and Donal hard at work at the serious business of extended range training.

Entering the water from a pier fully kitted with a twin set and stage bottle is not easy and may require the assistance of a buddy.

Donal lends his boot.

Practice makes perfect, so the next time that Donal comes across a serious pier blockage, he knows exactly what to do.

Don leads Jonathan to shallow end

I hope everybody enjoyed the pool training. Beginners, crossovers, existing club divers, and extended range divers all used the pool sessions to practice their skills and to try out new equipment before the start of the dive season. Thanks to everyone who helped out and loaned equipment.
Thanks to Donal O’Connell for the photos.
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IMG_3618

Originally uploaded by rf_keane.

Another shot of the divers decompressing after the Lusitania dive on 2nd July 2006

IMG_3620

Originally uploaded by rf_keane.

Divers Decompressing after 90 metre dive to Lusitania.
Bottom time was 30 minutes and dive run time was 180 to 210 minutes.