Wednesday, March 21, 2018

An evaluation of diving off Isla Mujeres, Mexico. Not the act of diving, but the logistics of diving and what you need to know

Isla Mujeres is a small island in the Caribbean Sea, about 8 miles off the Yucatán Peninsula and coast of Cancún, Mexico. The island is almost 4 1/2 miles long and a little over 2,000 feet wide. While it's not my intention to sell the island to travelers thinking of their next Mexican vacation, the island is not terribly overcrowded, the diving is pretty good, and the people are friendly. Click HERE to download several maps of the island that include:
  • Getting to know Isla Mujeres
  • Hotels and rental properties
  • Downtown attractions
  • Downtown restaurants
  • Restaurants around the island
  • Attractions around the island
  • and a "Golf8 Cart Tour"
My girlfriend and I stayed in Cancún and took the bus to the ferry terminal and rode over. It only takes 15-20 minutes and several of the boats are catamarans making the trip relatively smooth. We decided to do several days of diving. The dive shop offered a three day package of six dives which took us to several shallow reefs, MUSA (Museo Subacuático de Arte), and a couple of wreck dives.

The first two days of diving were pretty good. I don't have the stomach I used to as a kid so I always recommend taking a seasickness pill or two for the boat rides to the dive sites. The horizon is often in view and if the wind isn't blowing too forcefully, the ride won't be that rough. 

I was quite surprised at the size and details of the statues but the amount of sea life on the shallow reefs was the most impressive part of the dives. With relatively shallow dives in the 30 feet range it was easy for me to do 50+ minute dives and even finish with a sizable amount of gas left in my cylinders. These dives weren't particularly difficult however as I'll talk about a little later, I would have preferred a little more structure and organization around the dives.

There are lots of dive shops on the island so I did a little work to research what I wanted from them, the price I felt was adequate for what we got, and where we got to dive. As expected, the owner of the dive shop was friendly and helpful and the Divemasters were eager to please.

I planned this dive trip a little differently as we had other plans on the mainland and since our entire trip wasn't going to revolve around diving, I felt that this would be a great opportunity to take as little equipment as possible, see what rental equipment would be provided/offered, and have a perspective on the experiences that many of my students would have when off to their dive destinations as "referral divers."

We took our own regulators, dive computers, dive masks/snorkels, weight belts, dive lights, octo/console keepers, wetsuits, an SMB, a finger spool with line, and an underwater video camera. We rented BCD's, tanks, weights, and fins. While I expected that the equipment would be exceptionally older, they weren't as old as I thought they would be. 

So, let's talk about my experience, what I expected to happen, and what I really wish would have happened. 

Paperwork. We started our trip with a very limited amount of paperwork. We were not asked to show our cert cards or logbooks. The trip before this in July of 2017 to the Channel Islands was similar. The dive boat told us that it was our responsibility to have the appropriate training for the dives we were going to do. While this would have made sense if the introductions to the dives sites were a little more detailed, since the dive sites of the day were often decided at the last minute, divers wouldn't have had the opportunity to choose different days, dive sites, or opt out if conditions were not within their comfort zone. As a note, the paperwork was not certification agency paperwork.

Ironically, while I am pretty comfortable and capable of extraordinary diving conditions, as I get older I prefer to go a little slower and expect the quality of the dives (and conditions) to supersede the number of dives. When students tell me where they are going to complete cert dives (referrals), I feel that a more thorough plan is going to be part of their educational process. While I wasn't caught off guard, so much of the day on the water went faster than I wanted it to and have to admit that I took way too much for granted that I never do when I organize dive trips, excursions, and certification dives!

Rental equipment. While tanks and weights aren't traditionally taken when traveling, some of the things I teach my students (and that I will be modifying for my lessons) were off or incomplete. The tanks did not have current hydrostatic inspections (hydros) after the manufacture dates and there was no visual inspection stickers. I don't know what Mexico's laws on hydros are of what the shop's position on visual inspections are... While I was able to see the compressor that was used for air fills, I didn't inspect it or make it obvious that I was giving it a once over. While I didn't think about asking to see a certificate of inspection testing the air for contaminants from an outside agency, it will be on my list.

The BCD's were somewhat modern, non weight-integrated, jacket styles with standard inflators. I didn't do the BCD inspection I teach my students as they assembled our gear for us. I did move the BCD's lower as they were too high for my liking but that did get their attention. In one instance, the tank strap was not fed through the last slot on the plastic buckle. The octos hoses were bent over and fed through one of the d-rings on shoulder straps. 

The weights weren't standard uncoated lead weights but I think they were originally in kilograms but were not legible. They assembled the weights on our weight belts. The reason I brought our own belts was to make sure of an appropriate length I insist on. Belts that are too long present the risk of being tucked in and belts that are too short are difficult to ditch in a hurry.

While my girlfriend got full-foot fins on all three days, I got heel-strap fins but they did not have boots for me. They gave me neoprene socks. As expected, the fins did not fit well and rubbed off skin on my heels and the top of my toes. Suffice it to say I will never travel without my own boots and fins ever again! I never did in the past and perhaps I thought things would be different. I had the same experience in the past so to expect that anything was different was short-sighted. The last day and last dive my girlfriend thinks that the full-foot fins she got were the wrong size.

The boat. The boat was an open body fiberglass boat with an outboard motor and a standing station for the driver. The driver stayed with the boat during all the dives but I don't think he was a boat captain or had any experience outside of personal or on the job training. I did not ask. The boats do have to follow the harbors and beaches recommendations on departures. I believe the owner of the shop told me that a harbor master used to be in charge of this but it is now the responsibility of the the Mexican Navy. There were not life jackets on board; no emergency oxygen; no AED; the assembled BCD's and regs laid on the bottom of the boat and each other every time we hit a wave; there was a radio on-board. I did feel that we were going too fast for the trip out to the wreck on the third day. I got sick on the boat after the first dive. My girlfriend and I did not do the second wreck dive later that day.

Dive briefings. While I'm not sure that the Divemasters had an emergency action plan, I would lean on the side of "NO" as it was not part of briefing. The briefing talked about where we were going to dive but was lacking a formal "BWARF," "SEABAG," or "START" (PADI, NAUI, and SDI's dive briefing acronyms). We did get the hand signals for all of the sea life we were going to see and it seemed that the Divemasters were ringing their noise makers continually as they pointed out the fish. I'm proud to say I think we saw everything on the cards below!
If I was briefing the dives we did they would have started at the dive shop with an introduction of everyone to each other and then: 
  • Site
  • Environment/Emergency
  • Activity
  • Buoyancy
  • Air
  • Gear 
I'm proud that my briefings for open water divers are easily a couple of hours long. My perspective is that my students have never been in all that cold-water gear, wearing 70lbs of equipment, in 50 degree water, have ever dove in the Puget Sound, and there are special considerations about the dives we are about to undertake. While none of the divers on our Isla dives were completing certification dives as students, I knew nothing about them, their experiences, training, number of logged dives, and I never asked to see their logbooks! 

When I look back at everything that happened during the three days with our dive shop (not disclosed on purpose), I have to be honest and say that I blew it! With that said, if I was this complacent, even though I know I could have take care of myself and my girlfriend in the event of an emergency, I was never inconspicuous about being an instructor. I always like to think that I'm "on duty" but the reality of this experience is that I didn't want to step on anyone's toes. If I didn't want to and I'm the barber, I can guarantee that my students would not either!

Evaluation. I have an open water weekend in three days and while I will cover everything needed, it makes me really wonder what my referral students are experiencing on their open water weekends. I think it's fair to ask if everything needed is done, and while those are my general expectations, I can't control what other instructors and dive shops do. I feel comfortable sending my students that meet my standards to their dive destinations, however if my recent experience is any indication of what is out there, I might need to do more. I think a checklist for them to follow has potential however there is the possibility for an adversarial response from those that receive them. 

Here is a video of complete equipment assembly and testing that I teach at the pool and expected that I would do at the dive shop in Mexico...

Wednesday, March 7, 2018

I got a compliment from a student. It's on the NAUI website.

#scuba #scubadiving #nauiInstructor #whosyourdaddy #lookwhaticando
#naui #nauiworldwide

Holy shit! Look what I can do...!!! No one ever told me I got a compliment...

Who did it?

Monday, March 5, 2018

Response to Cave Diver Harry Article: Proper weighting

There is so much more about proper weighting. This is a great topic! Here is a list of things that are not talked about enough when it comes to proper weighting and that all new divers should be trained on! Oh, wait. I do... Does Patty? Who is this Patty everyone keeps talking about?

-- Aluminum cylinder or Steel cylinder: do you know the buoyancy characteristics of the cylinder you're diving on and when will a change of buoyancy be problematic. At the beginning of the dive, having too weight for how much air you'll be using out of your aluminum cylinder and at the end of the dive and not having enough if you take your tank down to 500psi. Starting the dive over-weighted only with the understanding that you must be cautious entering the water. There might be as much as a 5lb shift! If you are in steel, just because the tank stays negative you should still do a weight check. Consider the tanks ballast! If you switch from a LP steel 72 to LP steel 120, you will NOT need the same amount of weight on a belt/harness.

-- Did you learn to ditch your weight, a weight belt, in the pool only to have a weight harness in open water and NOT practice ditching the weight? Ditching weight from harnesses like the DUI is not easy for everyone. Similarly, integrated BCD's that are too tight might not release the pockets easily. You must practice ditching your weight in open water and your dive buddy must try to ditch your weight, too. Doing a BARFW and/or telling someone how you ditch your weights is NOT a proper buddy check.

-- Doing skills on your knees and negative is not a realistic for emergency skills. In the pool, meh... In open water? You MUST be neutral and in diver position so you can immediately decide if you're going to do a swimming ascent or buoyant ascent. If you are negative and run out of air, you are likely to start climbing the invisible ladder. See video on the YouTube "Diver Panic."

--CESA is done kneeling or standing are not representative of being out of air. Do the skill where you are neutral, at depth, then arch your back and get in a kick or two to be in the correct orientation (in a position to make an ascent). If you are going to continue swimming to the surface, your inflator MUST be in your left hand so you can orally inflate your BCD when you surface. In a real OOA situation, by the time you get to the surface from starting neutral there won't be much of a struggle to stay on the surface even without ditching weight (if properly weighted). If you are negative, you MUST ditch your weights and follow EBA procedures. Break the CESA into two parts: getting into proper position THEN a swimming ascent -- but separately.

-- Practice orally inflating the BCD underwater when air sharing with a buddy. Don't just say you're okay to go to the surface if you're negative. If you are negative, you need to add air to your BCD before trying to swim to the surface. If you are in a 2-piece farmer john wetsuit at 100ft and sitting on the ground and run out of air, you will NOT be able to swim to the surface until you get neutral. If you ditch your weight at 100ft, hold onto something because you'll be in orbit as soon as you breach the surface.

-- If you go to a warmer climate and a change of weight is necessary, don't let the Divemaster tell you to put 20lbs on! DO A NEW WEIGHT CHECK. Geeez, really?


Sunrise Motel, Hoodsport, WA. 101ft descent and swim to shore. Blog: Ave...

#scuba #scubadiving #divecalculator #deepdiving #pugetsound #hoodsportwa

Average Depth Calculator (spreadsheet) Download and why your dive computer is just an expensive calculator. Decompression theory...

For those that haven't used tables in a while, you can watch my two videos on Dive Tables by clicking on the two links below if you want to re-familiarize with them. Even if you don't, the tables basically tell us how long we can spend at particular depth for any given first dive. This assumes that the diver is making a direct descent from the surface, reaching their planned depth (but not going past it), spending an amount of time there, and then making their way back to the surface. The dive times that one uses in the tables above accounts for the total time in the water (including descents and the ascent). A safety stop is recommended but not part of this number. The diver can consider the end of the dive at 15ft and do their safety stop for 3 minutes after which they would exit the water.

NAUI Scuba Diving Tables: an Introduction and Question 53 of 63. How to use dive tables

The beauty of the dive computer is that it will calculate how deep you are at any depth and at a particular interval (the intervals below are one minute in duration however there are computers that you can change this value to as little as every 5 seconds but it will use more battery power), then add the next depth to that interval and divide all of that by how long one has been in the water. You could do this manually but your entire dive would be doing math, not exploring the amazing dive site you're on! Once you get to your 2nd, 3rd, 4th dive, all but a few could do the math quick enough and it's more likely you'll start making mistakes. One depth and one time is easy to plan for.

This first example below is a typical dive to boat #1, approximately 45ft max depth starting from the shore, looking around, and then making one's way back to the shore. The ocean floor at Sunrise Motel makes a gradual slope to the boat and when one averages the time one spends at any particular depth and then averages it among all the others, you can see that even a 45ft max depth dive, is really a 25ft dive!

If you go back up to NAUI Dive Tables on the top of the page, you can see that a 45ft dive has a maximum dive time of 80 minutes. I don't know about you but 30-45 minutes is a pretty good dive in 50°F water. So if we are taking on have of the amount of nitrogen that is allowed, our risk of DCS is low. If we then go to the table and look for 25ft, we have to drop to 40ft which gives us 130 minutes. Again, a very conservative profile.

These values are from the entire dive starting at the surface, descending to the ocean floor (101ft), then making my way back to the shore. At one minute intervals, one could do the math, but why?

Here is the entire video:

Now, if we look at the dive I dive from the surface above the deep boat, as I average my depths together, even this 101ft dive averaged over a 30 minute total dive time to all those varied depths only gives me an average depth of 44ft. Wow! Not only is my 44ft dive for 30 minutes rather conservative, if I was to use the dive tables for this dive, I would only get a total of 15 minutes in the water. But wait! 3 minutes to descend, 3 minutes to ascend, and only 9 minutes of bottom time. That sucks! Who wants to do a 9 minute dive?

What does it look like on my dive computer when I finally got close to my max depth? Not too far off from dive tables. At 94ft, that would give me 22 minutes according to the dives tables, and when I finally got to 101ft, only 15 minutes.

So, when someone says that dive tables are SOOOO conservative, well... NOT really. We have to be conservative due to the limitation for most divers' (technical decompression divers using tables on a wreck, excluded) inability to calculate a bunch of math in their heads.

Now, here is the crux of my point about dive computers being expensive calculators. Is there any real difference between a $2,000 computer and a $50 used computer you bought on Craigslist? Not as much as you might think...

Don't get me wrong, the dive computer has other features that are great to have. They log your dives, they tell you how fast you are ascending, they tell you how long you have to wait to fly (without waiting the default 24-hours), they do all the math for you, etc. 

When you have some time, download the calculator and play with it. Everything except the column should be locked so you don't change the calculations performed in each cell. The idea behind understanding what is happening to the nitrogen dissolving into your body is important! Tables or computers, it's up to you. 

WARNING: This also doesn't mean you can blow your bottom time because you'll make it up in the shallows, either. You require specialized training in order to do decompression dives and there are considerations you have to prepare for, but if you want to learn how, I can teach you how to do it safely. This overview is part of the understanding you need to know about.

Descending to 101ft to deep boat #3 at Sunrise Motel Hoodsport Washingto...