Weight, Buoyancy, and Streamlining

There are many tell-tale signs that your weighting is off underwater. For instance, you may balloon to the surface near the end of the dive. There are other, more subtle clues that your weights could use some fine tuning. One of these is how streamlined you are in the water.

Streamlining refers to your ability to maintain a horizontal position in the water. When you're overweighted, you have to compensate by inflating your BCD. This alters your center of gravity to the point that you are swimming with your chest high in the water (and your legs low).

When you're underweighted, you have to continuously kick down to keep yourself at depth, resulting in a profile position with your legs high in the water.

See the figure below for how each of these looks in the water. Also, take a moment to make the mental connection of how you might feel in each of these positions. This way, if it happens you become aware of it. Like I said, it can be subtle.
[StreamliningClick to enlarge][]

Correcting this problem has many great effects. First of all, you can more easily enjoy your dive when you are perfectly streamlined. Secondly, it'll improve your air consumption. It'll also reduce the likelihood that you inadvertently kick any aquatic life.

Fixing the problem may not be so easy as putting more weights on your belt (or taking them off), although you will want to try this at first. Play around with the location of your weights and see how it affects your balance underwater. You may find putting weights in trim pockets is more helpful.

For example, I use a weight-integrated BCD with around 10 lbs of weight (in tropical water). Most people might put 5 lbs in each weight pocket. However, I prefer 3 lbs in each trim pocket on my back, and 2 lbs in each weight pocket. This took experimentation and about four dives for me to fine tune, but it was well worth the minimal effort.

Also, if you find your legs are especially buoyant, you may want to consider using ankle weights to bring them horizontal. Basically, it comes down to observing your body underwater. Remain still for a moment and feel where your balance is, then think about how you can shift weight to make yourself centered. You will be amply rewarded in future dives.

[StreamliningClick to enlarge]: http://thedivingblog.com/uploads/2010/04/weighting.png

The Cove Review

I recently watched a documentary called The Cove. You may have heard its name in the past month for winning Best Documentary at the 2010 Academy Awards. In fact, that's what brought the movie to my attention.

The Cove
Between Avatar and The Cove, 2009 was a year for hippie movies. And make no mistake, The Cove is a hippie movie. Those with any warm feelings towards oceanic creatures like dolphins---and I would assume that includes all scuba divers---will get at least a little riled up by this film. Those who don't care probably won't bother to watch in the first place …

Dive Photo Guide

I don't have a fish ID article today, so instead I offer a link to Dive Photo Guide.

Dive Photo Guide is a pretty nifty site about underwater photography. This includes articles on photography techniques. They have monthly photo contests and a section listing underwater equipment options.

It has stuff for the non-photographer. In particular, check out the Galleries section for some great underwater photography; it can be inspiration for those of you who do take pictures.

Have a great weekend and I'll see you on Monday!

Can I Get Sued for Not Helping a Diver?

I am not a lawyer, and this is not official legal advice. In addition, laws vary between countries, so the situation can always be different for your country or the country you're diving in.

You won't get sued
I've heard dive professionals (divemasters and above) talking, in person and on places like ScubaBoard, about when they are diving on vacation (as opposed to diving while working). There seems to be a common sentiment: when the shop wants to see my C-card, only show them my open water or advanced open water card. The less they know the better.

There are two reasons to do …

Ted Danson, Sylvia Earle, and Seafood

On a recent Delta flight I found an article in Sky Magazine. It was about environmentalism overall, but a few pages in particular dealt with the oceans.

One section was about American actor Ted Danson's foray into activism. His page mostly focused on eating sustainable seafood and avoiding seafood with high mercury levels (like swordfish, which no one should ever eat). However, I found myself drawn towards the portion of the article about Dr. Sylvia Earle.

I've never heard of Sylivia Earle, but the article says she is referred to by her friends and colleagues as "Her Deepness"---an accolade …

Rescue Diver

Rescue me!
Telling people you're a rescue diver is fun. It evokes mental images of you jumping from helicopters into frigid waters like Kevin Costner in The Guardian. While becoming a rescue diver won't make you Ashton Kutcher, it can be a challenging and rewarding experience.

I'm coming from a PADI approach, but as we'll see, the information here applies to most of the larger organizations.

What is it?

Like most diving certifications, rescue diver has a knowledge portion combined with an applied, in-the-water component. The knowledge portion includes

  • Common causes of diver stress and dive emergencies
  • Identifying a diver in need …

What Entrepreneurs Can Learn From Diving

I came across this article about what entrepreneurs can learn from scuba diving. The article points you to a 128-page PDF document called "The Scuba Sutras", written by Guhesh Ramanathan. Ramanathan is a diver and businessman who has written up ten business lessons that parallel the sea.

The ten lessons are:

  1. I will never dive without a check.
  2. I will maintain neutral buoyancy.
  3. I will enjoy the dive, not just the fish.
  4. I will be a good buddy.
  5. I will not confuse expertise with certificates.
  6. I will respect the currents around me.
  7. I will remember that trigger fish can be …

Fish Identification: Flamingo Tongue

Fish are fun, but for today's creature identification we're going to talk about a snail (they're not just for escargot).

Physical description

[Flamingo Tongue Snail][]
Flamingo tongues are about 1 inch (2.5 cm) in length. They are easy to identify, because they are all white with small yellowish splotches across their shell. These splotches are lined with black.

Interestingly, this color is not part of their shell, but rather part of the animal's tissue that covers the shell. Divers and snorkelers like to grab flamingo tongues as "souvenirs" because of their pretty shells, only to find after the snail dies that the …

Shore Diving Tips

With two trips to Bonaire, a good portion of my diving has been from a shore. I love the freedom provided by not being stuck to a boat's schedule. Your dive can be as short or as long as you want, and the only other person that has to be considered is your buddy. Not to mention there are no half-hour boat rides to the dive site.

Shore Diving
It comes with its own set of challenges, though. Waves and surge can be rough, especially with all your gear strapped to your back. In addition, many sites have a variety of rocks …

What Diving Equipment Should I Buy?

Scuba dive for any length of time and you'll start wanting your own equipment. A natural follow-up question then is, "What equipment do I buy?" Let's look through all the equipment a diver needs, which you should buy, and in what order.

Scuba Dive Equipment
Your own mask is usually high up on the list of equipment to own. This could be for a few reasons. Having a properly-fitted mask increases the comfort of your dives. Masks are one of the more "personal" items you own, so having your own that you are comfortable with is an advantage. They also are small and …