Tag Archives: Tec Diving

General Guide Lines Covering All Dives (Tec or Rec)

I have been reading an interesting manual from IANTD and I could not get over how much this makes sense, so I thought I would share it with my readers!

  • Analyze all gases prior to diving;
  • Ensure all gases are properly and visibly labeled prior to diving;
  • Use 1.4 PPO2 on technical level exposures as a bottom and 1.6 as a maximum decompression mix PPO2[singlepic id=221 w=320 h=240 mode=watermark float=right]
  • After a period of acitvity at the surface (kitting up), allow for a short rest period in order to get breathing and heart rate back under control prior to entering water.  Experienced divers may use visualization techniques or bodycardial breathing to achieve this.  In short, wtop whatever you are doing and breathe deeply for a period of time;
  • During the descent, stop at 20ft (6msw).  Perform a leak and general equipment check.  THis wait time of an additional minute or so further allows the body to acclimate to the new environment.  Temperature and light acclimatization may take several minutes (up to 25 minutes for major light changes), however this brief stop will allow the cardio-vascular system to return to near normal rates.
  • Make a slow descent without excess exercise.  Either free fall or use hand over hand techniques with shot lines in tidal areas.  Finning down the line will use a lot of energy and produce CO2 that in turn predisposes us to narcosis and a range of other problems.
  • Having reached the bottom take another brief period to adjust equipment and attain the correct buoyancy.  All these extra stabilizing minutes are simply an attempt to return the body to a near surface functioning state such that it operates to maximum efficiency.[singlepic id=136 w=320 h=240 mode=watermark float=right]
  • During the dive, whenever possible use “pull and glide” techniques rather then heavy finning (with suitable respect for the environment).  Use of the arms reduce breathing stress.
  • If at any point during the dive a stressful situation arises, STOP, take 3 deep breaths (focus on breathing out), Think and Act in that order.  Try and prioritize the problems.  The bottom line being if I have gas I can breathe.  There is no urgency to start an ascent if at the end of the planned time something happens which slows egress providing bailout schedules are (and should be) carried.
  • If the depth of the dive is known, carry a schedule for the dive time and the dive time plus 5 minutes.  If the depth is uncertain carry a schedule for the depth and the time and the depth plus at least 10ft (3m) and the same time.  Carry an additional schedule for the longest time and deepest depth assuming a decompression on bottom mix.
  • Always plan for the deepest part of the dive even if this portion is only a bounce, i.e. if the wreck bottoms at 229fsw (70 msw), but most of the dive is at 223fsw (68 msw), plan for 229 fsw (70 msw).  Maintain ascent rates of 33ft/minute (10 m/minute) or less, even from deep water.
  • As with a no-stop dive where it is wise not to return directly to the surface (as this is a calculated pressure ceiling), it is also wise not to return directly to the  first decompression stop.  One or two minutes spent waiting 10fsw (3msw) below the first stop are beneficial when considering tissue over pressurization and will have no noticeable affect on the remaining decompression.
  • Avoid unnecessary deplays in deep water on bottom mix, such as starting up a wall after planned bottom time and then taking time to stop and look.
  • Do not reduce stop times arbitrarily.  Do not make assumptions on stop time reduction if using a non planned gas without first computing for the effects.  In a team plan this would mean carry a schedule for the worst gas scenario of the team (most deco).
  • When reaching the first stop and if using a time device which works in whole minutes.  Wait until the minute has incremented and then start the timing at that stop.[singlepic id=138 w=320 h=240 mode=watermark float=right]
  • If the stop involves a gas switch, start the stop timing after at least 3 – 4 breaths using the gas.
  • Maintain stop accurracy to +/- 1fsw (.5 msw)
  • After completing the final stop, ascend half way to the surface and stop for a further 2 – 5 minutes.
  • While waiting for the boat to pick you up, stay on the highest available FO2
  • Upon entry into the boat after a period of decompression, spend at least 5 minutes breathing your highest available FO2 on the surface.
  • Hydrate with non-acidic drinks at least 12 hours before planned extended decompression dive.  Hydrate again prior to the dive and immediately afterwards
  • Avoid alcholic beverages, caffine and decongestants prior to diving.
  • Do not smoke, especially immediately before and after a dive.

These points are pretty much common sense things, but how many people skip past some, out of complancy??

9 mile Tec Dive

[singlepic=137,320,240,watermark,right]Uwe and Suncoast Diving was up to 9 mile point doing another Tec dive.  Neil and Mike were up from Vancouver to do another of their Technical dives.  Though we had a later start then normal overall it was well worth the wait.

Upon arriving at 9 mile we could quickly tell how good the visibility was going to be.  Tide was high, but in 30 feet of water we could clear see the bottom while we were still sitting in the boat.  Due to the cold surface temperatures we decided to cut back the lenght of the bottom time so we would not have to pay for it back at 20 feet, in the middle of the cold surface layer.  Sam was the dive leader for todays dive, and she did a wonderful job getting the group to the bottom and headed down the crack to the deep wall.  Once [singlepic=135,320,240,watermark,left]down, we settled into a nice easy swim so we could enjoy the sites, the topography at 9 mile is a amazing.  The wall is covered with tube worms, sea cucumbers and other marine life.

Overall the dive was good, good visibility!!  Uwe and Suncoast Diving is going to be up the inlet on Saturday to do a wreck course and Drysuit course.  If your interested be sure to stop by the shop and sign up!!

New Decompression Diver

[singlepic=135,320,240,watermark,left]Uwe would like to congratulate Mike J. and Neil P. for their successful completion of Advanced Nitrox and Decompression Procedures from TDI.  The guys started their training in early Sept, with two days of intense skills dives.  Their training was put off a couple of weeks due to some ear problems and equipment problems at the shop.

Deco Dive 1, was out on the HMCS CHAUDIERE which is an exellent training platform as it is easy to get depth fast, and also have an easy ascent line for the deco stops.  We enjoyed a nice swim through up through the operations room, into the bridge and out through the lower point on the bridge deckhead. [singlepic=137,320,240,watermark,right] Overall the dive plan was 150 for 20, and the final stop was 8 at 20 feet.  Nothing like a gas switching computer!!

Deco Dive 2 was completed today at the Tuwanek Abyss…the water temp is cooling and visibility was pretty short in the top 10 feet.  Once we broke through the top layer, the visibilty opened up to easily 100 feet, and crystal clear. We slide down the sand with the wall tight on our right….the wall had some nice chimney sponges on the wall.  We used V planner for the first time on the dive, though a bit different then the Deco Planner we normally use, it certainly has some great potential…so more investigation is needed.

Once again, congrates, and thank you to Suncoast Diving!!

New Decompression Diver

[singlepic=102,320,240,watermark,left]Uw Explorers wants to send out our congratulations to Jeremy Chesworth on completing the Advanced Nitrox and Decompression procedures course yesterday!  We planned to challenge Jeremy with a dive to 170fsw off 9 mile point.

Monday night had everyone hard at work preparing decompression mixes for the dive, while some prepared the decompression schedule for the dive.  Once completed we broke for the evening with the agreement to meet early the next day so we could get everything together and out to the dive site.[singlepic=138,320,240,watermark,right]

Once on site, we preped and rolled into the water….did our bubble checks…and then started our descent.  As we dropped through the 50 foot mark we could tell there was a bit of a current.  So our intial swim was going to be a but harder then expected but there were no problems as we finally arrived at the scar that leads to the deep drop off!  Visiblity was at least 150 feet, and water temps were still good for decompression!!

Overall it was a great dive…interested in becoming a Tec Diver…be sure to check our courses tab right here at the website!!

NOTOX gas switching

[singlepic=99,320,240,watermark,right]This seems to be one of the big searches that brings people to the web site.  I have had many people ask me what is NOTOX and where is the definition found.  Well, it is certainly in the DSAT Tec Deep book as well as the Tec TRIMIX also from DSAT.  I thought I would include the definition as it is found in the DSAT Tec Deep instructors manual.

NOTOX;

N –  Note your name and the maximum depth on the cylinder labels

O –  Observe your actual depth and compare to the MOD

T –  Turn on the valve, Check the cylinder preasure

O –  Orient the second stage by pulling it from the retaining bands.

X –  eXamine your team mates – follow the hose form their mouth to the stage bottle.

So that is the NOTOX switch.  Remember “one of the most common preventable causes of technical diver deaths is switching to the wrong gases for the depth.” So get out there and get tec diving!!  Not trained, let me know, I will be more then happy to do your training for you.

Deco Procedures : Sechelt

[singlepic=136,320,240,watermark,left] UWE started up another Advanced Nitrox and Decompression Procedures course on the 9th of Sept.  Neil and Mike came up from Vancouver to work on this course, so we had two very full days of training.  We were able to tackle the academic work for the two courses…plus touch on some of the work on the DSAT Gas Blender course.

Tuesday was spent working out equipment for configuration, once that was completed it was out to Tuwanek[singlepic=138,320,240,watermark,right] for 2 skills dives.  S Drills, V drills, donning and doffing stage cylinders, with and without masks, and don’t forget bag drills and SAC rate calculations.  It was close to 7 pm when we were leaving Tuwanek…on the way back to Suncoast Diving, for some gas mixing and more knowledge reviews.

Wednesday morning was spent completing the remainder of knowldege reviews, analyizing gas, and prepping the boat.  We were out on to the water for 12, and off to Tuwanek point, where the first dive of the day had us on an extended range gas switching no decompression dive.  The main purpose of this dive is to utilize the [singlepic=139,320,240,watermark,left] NOTOX switch as well as introducing the second stage bottle.  Finally, we dropped in for a 30 minutes skills dive, with surprise skills, S Drills, V Drills…and donning and doffing of stage cylinders!!

Overall this was an excellent 2 days of training, Neil and Mike completed the Advanced Nitrox section of their trianing…now we just need to do some decompression dives!! Stay Tuned!!