Tips on Basic BCD Maintenance

I have been told that I need to write about something for the blog, but I did not know what to write about. That was until I worked on a regulator that just made me sad. It was in such bad shape; it was not taken care of at all. So the idea of me writing about basic equipment maintenance started to make since to me. Because as most of you know, "the world of scuba is all about me". :-) And the best way to make me happy is to ensure you are taking care of the gear you depend on, not only for your life while underwater, but to make sure you have that successful dive at your local dive spot or while you are on a dive trip somewhere in the world.

Let’s begin with your BCD:

Before you pack your BCD into you dive bag, you should check to make sure you have all the parts for it, like your weight pockets and clips. You should also check to see if the quick release system is functioning and that the webbing is not starting to tear. Do the dumps have the cords still attached? Are any of the connection points (seams) no longer intact? It doesn’t take long to check this stuff out, but it is important.

Now, I am not too concerned about your ability to put your gear together for your dive, so let’s get to the post-dive activities. Once you get home, you should wash your gear in fresh water that has some type of BCD/wetsuit conditioner in it. The conditioner will help to break down the salts while you rinse out the sand. Of course, you can buy this stuff from The Dive Shack. Most people when they wash their BCD just dunk the unit into the water a couple of times, or them may let it sit in the water a bit before they hang it up to dry. I have a vial at the shop with some pretty large pieces of rock salt that I was able to get out of the air bladder of a few BCD’s over the years because of a step most people forget. When you are done washing the outside, you need to wash the inside.

While we dive, as we deflate the BCD with the black button at the end of the inflator hose, we allow some water inside the bladder of our BCD. The more often or longer we hold that button down, the more water we get inside the system. This is not really a bad thing, but if you don’t clean it out after the dive, the water will evaporate out leaving salt crystals to accumulate in the bladder.

Here is what you should do. When you have your water hose flowing, put a little air into your BCD, then lift the inflator hose up and push the oral inflate button down. With that done, put the water hose up to the inflator and allow the fresh water to go into the BCD. I should fill it up with about a couple cups of water, then release the button. Next, lift the BCD up and move it around, sloshing the water all over the inside of the bladder. Once that is done, you hold your BCD upside down with the inflator hanging down at the lowest point, then depress the deflate button to drain the water out. Sorry, but not done yet. Repeat, slosh and drain again, but this time taste the water. If it has a salty taste to it, then you need to refill, slosh, and drain again. Do this until the water has a fresh taste to it. Now you know there is no more salt in the BCD and it can be hung up to dry.

When you do hang it up, just remember to add a little air inside. It does not need to be full, just one or two full blows to keep the inner material from sticking together as the moisture dries out.

All of this does not take long and it will make sure your system will look better, work better and last longer. Plus, if you bring it into the shop for a full service, I will not be sad when I have to see a poorly treated piece of equipment. (Remember: "the world of scuba is all about me". :-))

Next time, I will talk about regulator maintenance. But until then remember, while diving, your equipment will not only help you have a great dive, but will keep you alive. I am sure you have heard the saying “the better you take care of your gear, the better your gear will take care of you.”  HAPPY DIVING!

Humble Beginnings

I first got into photography because I was looking for an art form I could use to express myself. As I pondered my choices a few things became evident. Since I am unable to tell if a line is straight (much less draw one - even with a ruler) I realized that most forms of drawing and painting were out of the picture. I pondered abstract or expressionism and smiled as I pictured myself pushing blobs of paint around on a canvas. Suddenly I had multiple flashbacks to all of the times I have tried painting things (rooms, fences, little sisters) and realized that I would go broke buying cleaning supplies. Pottery sounded intriguing, until I pictured the wheel spinning out of control and blobs of clay taking out walls in the house. You see, I have a bottomless talent for making a mess and breaking the unbreakable.

I sat on my couch staring off into space trying to come up with my creative outlet. After a while I realized that I was staring at the book on the coffee table. Inspiration struck! It was an Ansel Adams book that I loved. His shots never failed to set me off into daydreams of rock climbing or hiking or tree climbing. I realized that I would make a minimal mess (unless I started developing my own film - which still interests me...) and had a pretty low risk of destroying my home if I took up photography. I informed my husband of my wish for a "real" camera, the kind where you could change the lens. Being the generous man that he is, he immediately bought me my first SLR. It was a Canon Rebel.



A first attempt at an art shot just resulted in

a serious case of "centeritis".



When I got my Rebel, I poured over the little instruction book. There were many pages on all of the different automatic settings and when to use them. There were maybe three small pages on the manual settings. I memorized these pages (at least I thought I had) and then set out to shoot. I set off for a water fountain because I wanted to get one of those pictures with the soft ethereal looking water. I remembered I needed a slow shutter to do that, but........which control was the shutter? Was it the f number thingy or......? I couldn't remember, so I tried all of the different settings and then eagerly mailed my film off for processing (you see these were going to be art prints so I couldn't trust my film to the corner drug store 1 hour processing, any fool could tell you that). A week later I got my prints. There were a couple that came close to what I wanted but at that point I couldn't for the life of me remember which settings I used to get them.



I loved this shot, but had no idea howI got

it, or how to repeat it.



And so began my photo journey - using the automatic settings in the camera. I got some good snapshots that way. But I felt like I was not an "artist", a true photographer, by using them. And when I did happen to take a decent shot, I was at loss as to explain how I got it or how to repeat it. I kept promising myself that someday I would learn how to really use my camera. Then one day, I opened the quarterly Adult Ed brochure that came to my house. There was a Digital Photography class. (Chris had upgraded my old film Rebel body to a digital one, I think he was sick of paying film processing fees.) The class description asked: Do you want the most out of your digital SLR? (yeeeees) Are you ready to take that bold step toward manual control? (YES YES!) So I signed up on the spot.

To be continued.......

Creature Feature : Mantis Shrimp

Marine crustaceans of the Stomatopoda order, mantis shrimp were named for their physical resemblance to the praying mantis. They appear in a variety of colors from browns to bright neons, and may grow up to 12 inches in length. [1] Most species live in the tropical and subtropical waters of the Indian and Pacific Oceans between eastern Africa and Hawaii, although some live in temperate waters.

Fairly common animals, they often go unnoticed because they spend most their time hiding in burrows in the seabed or holes in rock formations. Important predators in shallow waters, mantis shrimp are known for their powerful claws which they use to attack and kill prey by spearing, stunning or dismemberment. [2] Unlike most crustaceans, mantis shrimp will not just wait for prey to happen upon their lair, but will actually leave their homes to hunt, chase and kill prey. They can be diurnal (active during the day), nocturnal (active at night) or crepuscular (active during dawn or dusk), depending on the species.

The mantis shrimp is often divided into two groups depending upon the type of claw they possess:

• Spearers are armed with spiny appendages topped with barbed tips, used to stab and snag prey. They use their barbed claws to slice and snag the meat of softer animals, like fish.
• Smashers, on the other hand, possess a much more developed club and a more rudimentary spear (which is nevertheless quite sharp); the club is used to bludgeon and smash their meals apart. Smashers use their ability to attack snails, crabs, molluscs and rock oysters.

Regardless of which group they are placed in, these shrimp use their claws to strike by rapidly unfolding and swinging them at their prey. They are quite capable of inflicting serious damage on victims significantly greater in size than themselves.  Because they strike so rapidly, they generate cavitation bubbles between the appendage and the striking surface. [3] The collapse of these cavitation bubbles produces measurable forces on their prey in addition to the initial impact of the claw, which means that the prey is hit twice by a single strike; first by the claw and then by the collapsing cavitation bubbles that immediately follow. [4] Even if the initial strike misses the prey, the resulting shock wave can be enough to kill or stun the prey.

Strongest Punch in the World... [5]

Close-up of the trinocular vision of
Pseudosquilla ciliata
photographed by Shumpei Maruyama

Mantis shrimp have eyes mounted on mobile stalks which constantly move independently of each other and are considered to be the most complex eyes in the animal kingdom. [6][7] Designed with trinocular vision, they can see objects with three different parts of the same eye and have enhanced depth perception. They perceive both polarized light and hyperspectral color vision (more than red, green and blue bands of light). [8]

The eyes of mantis shrimp may enable them to recognize different types of coral, prey species (which are often transparent or semi-transparent), or predators, such as barracuda, which have shimmering scales. Alternatively, the manner in which mantis shrimp hunt (very rapid movements of the claws) may require very accurate ranging information, which would require accurate depth perception.

Mantis shrimp are long-lived. In a lifetime, they can have as many as 20 or 30 breeding episodes. Depending on the species, the eggs can be laid and kept in a burrow, or carried around under the female's tail until they hatch. Also depending on the species, male and female may come together only to mate, or they may bond in monogamous long-term relationships. [9] In the monogamous species, the mantis shrimp remain with the same partner for up to 20 years.

Mantis shrimp exhibit complex behaviour, such as ritualised fighting. Some species use fluorescent patterns on their bodies for signalling with their own and maybe even other species, expanding their range of behavioural signals. They can learn and remember well, and are able to recognise individual neighbors with whom they frequently interact. They can recognise them by visual signs and even by individual smell. Many have developed complex social behaviour to defend their space from rivals.

Hemisquilla ensigera californiensis - Californian Mantis Shrimp

How dangerous are the strikes of common mantis shrimps to humans?

"I handle stomatopods every day in our lab and when I'm in the field it is not uncommon to measure and sex 150 animals in an evening. Needless to say, I'm struck fairly often. Some species are far worse than others, but it usually hurts. Even a 2 cm Gonodactylus can draw blood and a 4 cm animal can drive the dactyl tips to the bone. Aside from a two inch slice in my hand made by a large lysiosquillid (by the uropod spine, not the dactyl), the most severe injury I have incurred was from a 7 cm Gonodactylus chiragra that drove its dactyl into the joint of my index finger and the tip broke off. It took some minor surgery to remove it. But that is nothing compared to what happen to a diver from South Africa who wrote me a few years ago describing his attempt to grab by hand an 18 cm Odontodactylus. The animal severely injured his finger which became infected by a chiton-digesting bacteria. The infection did not respond to the usual antibiotics. In the end, they amputated the finger. Be careful out there!

- Dr. Roy Caldwell

Web Site Author: A. Sunjian Note: There are newspaper reports of large Hemisquilla cutting off people's fingers with one strike, although how much credence can be given to stories like these is open to doubt."

References

1. James Gonser (February 14, 2003). "Large shrimp thriving in Ala Wai Canal muck". Honolulu Advertiser. http://the.honoluluadvertiser.com/article/2003/Feb/14/ln/ln01a.html. 
2. Ross Piper (2007). Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals. Greenwood Press. ISBN 0313339228. 
3. S. N. Patek, W. L. Korff, and R. L. Caldwell (2004). "Deadly strike mechanism of a mantis shrimp". Nature 428 (6985): 819–820. Bibcode 2004Natur.428..819P. doi:10.1038/428819a. PMID 15103366. 
4. S. N. Patek & R. L. Caldwell (2005). "Extreme impact and cavitation forces of a biological hammer: strike forces of the peacock mantis shrimp". Journal of Experimental Biology 208 (19): 3655–3664. doi:10.1242/jeb.01831. PMID 16169943. 
5.  Strongest Punch in the World on YouTube.
6. "Mantis shrimp have the world's most complex colour vision system." - Justin Marshall, University of Queensland
7. Patrick Kilday (September 28, 2005). "Mantis shrimp boasts most advanced eyes". The Daily Californian. http://www.dailycal.org/sharticle.php?id=19671. 
8. Justin Marshall & Johannes Oberwinkler (1999). "Ultraviolet vision: the colourful world of the mantis shrimp". Nature 401 (6756): 873–874. Bibcode 1999Natur.401..873M. doi:10.1038/44751. PMID 10553902
9. "Sharing the job: monogamy and parental care". University of California, Berkeley. http://www.ucmp.berkeley.edu/aquarius/monogamy.html.
10. The Lurker's Guide to Stomatopods - mantis shrimp 
11.  Californian mantis shrimp (deep sea) on YouTube.