To stage or not to stage, that is the question we want to address with this article. To most technical divers this statement will be the start of an interesting and often times lively discussion. Some will tell you that you should NEVER take a gas deeper than the depth you can breath the gas. Say you and your dive buddy plan to make a dive to the depth of 185 feet with a bottom run time of 40 minutes. You are planning to use 50% enriched air mix and oxygen as your decompression gases. Keep in mind that your total run time on this dive will be at least 111 minutes. If you elect to to stage your bottles this means you would leave one bottle behind at 20 feet (oxygen 1.6 ppo) and the another at 70 feet (50% nitrox mix at a 1.56 ppo). Generally speaking this is a not a problem if you are very familiar with your dive location and you are absolutely positive you can find each bottle on the way back home. Remember your life depends on you and your team being able to re-locate your decompression cylinders.
Thursday, December 10, 2009
Yet others, including me, will tell you to NEVER leave your decompression cylinders behind. Same dive as before, 185 for 40 minutes, but you carry your decompression cylinders with you throughout the dive. Now you know where your cylinders are, they are your constant companion and these cylinders will be available in the event you would need them. For example, you have an issue during your dive, you now have additional resource(s) available to you to assist in your decision making process. You and your team enter into a dive that has an aggressive current, poor visibility, or the combination of the two. You may not be able to find your way back to your entry/exit point, or you may not be able to get back to your bottles. A drift dive decompression on a SMB (surface marker bag) may be your only option and without your decompression cylinders this may be a difficult if not impossible task.
Now all that being said, whether you elect to stage your cylinders or take them with you, both procedures are correct. This is a diver preference or better stated a dive team preference. Consider this a mandatory function of your dive team, all members of your team must agree on the procedure for the specific dive prior to each and every dive. So talk it out.
I would like to share a story on this topic. There we were diving some of the most interesting wrecks in the world and we got on the topic of staging or not staging cylinders. Our story teller spoke of a life experience that changed his mind forever on the topic of staging.
We had been told of a dive in the South Pacific, he was the team leader and he was taking 5 other divers with him on this dive. All of the divers had planned their dive and as they had done so many times before planned to stage their decompression cylinders on a descent/accent line at each of the appropriate stop locations. They entered the water and began their dive. They staged their decompression cylinders.
It was an exciting dive and the divers have an opportunity to see a vast majority of this deep wreck. Exploring the inside and exterior they use all of their planned time at depth accruing decompression time. They agreed the dive is at its turn point and they began to make their way back to the accent line. When they arrived at the descent/accent line they found that the line was gone...in fact the entire bow of the ship was gone. Evidently a freak storm had come up. The combination of strong winds, high seas and the weight of the dive vessel had pulled the anchor line so hard that it severed the dive vessel from the wreck taking with it a portion of the bow of the wreck, all of the decompression cylinders, and the accent line. Now 6 divers were in distress and in vital need of decompression gases. Thankfully another vessel was able to answer the distress call and all divers we given access to additional decompression cylinders.
Obviously this is a dramatic example of why you should take your decompression cylinders with you on your dive.
I too believe that on all deep open ocean dives it is a very prudent decision to take your decompression cylinders with you.
Posted by Miller Diving at 9:01 PM
You have been thinking about technical diving for some time now. But you have questions. I think everyone that explores this type of diving and training does. I know I did when I first started down the road to certification as a technical diver.
For some the enrollment in a technical diving program is a natural progression. They have finished the prerequisites and they are looking to expand their knowledge and diving skill set. Others look at technical diving as an opportunity to stand out from the crowd. To go where very few have been before. After all this is an elite group of divers that are exploring depths well beyond traditional recreational diving limits and to some that has an attraction. Regardless of your motivation you more than likely have questions and you most definitely need a comprehensive training program.
You undoubtedly have asked yourself a series of questions similar to these: Is technical diving for me? How much will the equipment cost? What can I do as a technical diver that I couldn't do as a recreational diver? What are the risks? What are the gains? How often will I use my technical diving skills? Where do I dive? What will I learn? Once I have completed my technical training what is next? Trimix? Gas Blending? Trimix Gas Blending? Expeditions? Travel? How do I technical dive in and around shipwrecks? And the list goes on and on. But these are great questions and a very good start.
Probably one of the least expensive ways to answer most of these questions is to buy your instructor a cup of coffee and ask. Plan on at least an hour as the questions will not be answered with a one word responses and your first question will no doubt stimulate additional questions. I would encourage you to write your questions down, that way you won't forget vital topics, and take notes on the responses these notes will help you refresh your memory and help you make your decision on this program.
An addition resource is the DSAT Tec Deep manual. I would recommend that if you are thinking about this course of instruction you purchase the manual and read about the philosophy of the course, course performance requirements, course structure, and equipment requirements. This will be helpful in answering questions you may have about the training process.
And if you want a candid up front discussion on the DSAT Tec Deep Diver program call me at 206.396.9221 or drop me a note at MillerDiving@msn.com.
We believe in training...training is the key to survival. Not interested? No worries, technical diving is not for everyone!