Tag Archives: Tec Deep

Are you Prepared??

This is from a poster that was created by the famous Cave Explorer Sheck Exley;

Sheck Exley What If Chart....
Sheck Exley

Before the Dive, What if…;

  • The gas company put the wrong gas in the cylinders you fill from?
  • The wrong grade of helium is in them?
  • THere are impurities in the gas?
  • You miscalculate your mixtures and have too much oxygen?
  • Too little oxygen?
  • Too much Nitrogen?
  • Too much Helium?
  • The for mixing is wrong?
  • The filling temperatures are different?
  • The dive shop filling your tanks allows the gas to bleed back into their bank system?
  • Your cylinders contain flammable materials and you put in pure oxygen?
  • The dive shop tops your deep tanks with bad air?
  • A pinhole leak allows the helium to leak but other gases remain?
  • Your get the cylinders mixed up while filling?

One the Descent, What if…;

  • You do not have enough oxygen when you submerge?
  • Your depth gauge reads shallow?
  • A tank you thought had trimix was really nitrox, etc?
  • You over breath your regulator?
  • You have a delay before ascending?
  • You have a delay on the way down?
  • You have to exert a lot on the bottom?
  • You have a five minute line entanglement etc, on the bottom?
  • You lose your dive partner on the bottom?
  • You get blown from the dive site?
  • You lose your mask?

During Decompression, What if…;

  • The decompression tables you have don’t work?
  • You lose your decompression tables?
  • You lose your watch?
  • You lose your depth gauge?
  • You run out of decompression gas?
  • You drop one of your decompression cylinders?
  • Some steals on of your decompression cylinders?
  • Your decompression cylinders have leaked?
  • You are delayed at a decompression stop?
  • Danger from hazardous marine life keeps you from completing your decompression?
  • Your drysuit floods?
  • You get hypothermia?
  • You get the bends

These are all the situations one should think of when Technical Diving…and be sure you can accept the risks!! Otherwise do not do it!!

Diving with the Master!

[singlepic id=107 w=320 h=240 mode=watermark float=left]Yesterday certainly turned out to be an amazing day,  I had the opportunity to dive with Tony Holmes, my mentor the guy who taught me everything I know about diving and what a pleasure it was!!

We originally had a charter booked headed out to the HMCS CHAUDIERE, and as always I was looking forward to diving it, plus I would have the chance to get more footage of the wreck, something I certainly would not turn down….but who to dive with.  The charter was going to be a Tec Dive, with two on doubles and one on a rebreather….and I certainly was not in the frame of mind to do a long cold hang at 20 feet.  Out of the blue, Tony called the shop and said he was hoping to get out for a dive or two for the weekend, talk about timing!!

Once everything was loaded on the boat, it was off to the boat launch and the trip up the inlet.  With the sun being out, it made you think of the soon to be summer, though the air was still pretty crisp as we skimmed along the wave tops.  Once on the dive site, we tied to the stern line on the wreck, and began getting the Tec guys read…first in was Owen on the rebreather, then Keith and Jessica.   As they disappeared into what appeared pea soup, Tony and I prepared for our entry.  Determined not to hang at the 20 foot mark on a long deco, away we went.  Happily I slide into the follow position on Tony, and the tour began!

We swam the distance of the wreck and slide up through the hole at the 130ft mark, just back from the bow which leads into the forward crews heads and wash place, from there we went up through the door on Berma Road that takes you into One and Two Mess.  Normally once in the Mess we would ascend through the exit point which is overhead, but on this dive Tony decided to head straight into an opening that leads into the forepeak which eventually lead to the outside of the wreck.  This turned out to be an excellent penetration, and I was able to get some good footage, though I am pretty sure this is where my troubles began.  Since we were in the higher profile 120 cuft steel tanks I got my valve caught on the hatch combing, and had to wiggle through the opening.  Unbeknown to me, this must be the point where my 8 pound weight pouch got caught and dropped.  As when I got through the opening I was very light all of a sudden and had to dump some air from the BCD.  Though not a big problem at this point…that would not be the case when I had to maintain my depth on what was going to be a 16 minute decompression stop.

Once we came out of this penetration we headed up and over the bow of the CHAUDIERE, where we got our first glimpse of Owen on his Megladon Rebreather, it always amazes me how quiet they are.  We headed off to the penetration at the bridge where we would go in the lower hole on the bridge roof, and ascend up through the brdige to the Ops Room ladder which leads into ops, and through the Sonar control room, our exitpoint is overhead that leads out through an opening on the stardboard side of the boat.  As we proceeded aft and to our ascent line we did two more penetrations, one which was new for me, and then the final one on the stern, and out to the ascent line.

As we started up to our first decompression stop it was obvious this was not going to be a routine hold for me, as the I was about 8 pounds two light, and I had to wrap myself around the ascent line in order to maintain the 20 then 10 foot stops.  Thankfully it was only 16 minutes of a hold.

As always another great dive, I certainly have missed diving with Tony, something I hope we will get the chance to do again in the near future.  If you are interested in doing the Wreck Specialty or Advanced Nitrox/Decompressions Procedures go to the Courses page on this site, and see what it is all about!

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??

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.