Around the Web

In today's update I'll share a few links from around the internet: has a several post series of Florida Keys dive sites. It certainly has me intrigued enough to get down to the Keys.

Alive2dive gives a rundown of personal gear selection. It's similar to our article on which gear to buy, but check it out for another opinion.

PADI Instructor News gives a breakdown of the new PADI open water prescriptive lesson guides and the new PADI Pro site (which is much better than the old one).

Tony Wu's underwater photography blog has a lengthy 3-part review of Aperture 3 software. Most of it is not anything specific to underwater photography, but it's interesting to see how a talented underwater photographer uses his software.

Duane at Precision Diving has an article on five characteristics of a good scuba diver. How many describe you?

Lastly, AquaViews has an article on brushing up your scuba skills, starting with mask clearing. I probably wouldn't be that interested, but it has video, which could be useful for those still getting the hang of it or who haven't been diving in a while.

Have a great Wednesday!

I'm always on the lookout for scuba diving blogs with great content. If you have one or know of one, please share.

Decompression Theory

As a scuba diver, theoretical knowledge cannot always be immediately recognized as useful. It does, however, come in handy. If you decide to move on to a professional level of certification, theoretical knowledge development is a requirement. It can also provide understanding behind practical decisions, guiding your reasoning in a more educated manner than just following a set of rules. Today we're going to talk about the biggest theoretical area there is for scuba divers, decompression theory.

Decompression chamber The need for decompression theory arises from decompression sickness (DCS). DCS encompasses the illnesses that may occur from the body's exposure to varying …

The Peeing Myth

Peeing in your wetsuit, it's right up there with death and taxes as one of life's certainties. Even so, our civil sides don't like to talk about it; especially that great feeling it gives you on a cold dive. It warms you right up from the inside out---or does it?

I've been reading that despite what you might think, peeing in your wetsuit will not actually warm you up. What happens is that the warm urine opens up the blood vessels near your skin's surface. These blood vessels think they are no longer cold and relax. Then, shortly thereafter, the …

Fish Identification: Yellowtail Snapper

Today's fish is the yellowtail snapper, or sometimes just called the yellowtail.

Physical description

[Yellowtail snapper][]
Being a snapper, the yellowtail has that perfectly shaped oval "fish" body. The caudal fin is deeply forked, hinting at the swift movement of this active fish.

A yellow line marks this fish, beginning at the snout and widening down the length of the body until it covers the entire tail, hence the name.

Yellowtail snapper can grow up to 30 inches in length, although lengths of around 12 inches are probably more common in diving environments.

Geography and habitat

Yellowtail live in the western Atlantic …

Oceans Review

"To really know the ocean, you have to live it." This line from the opening narration is something every scuba diver can relate to. We spend our whole lives getting to "know" the ocean, but DisneyNature's Oceans documentary gives us a 1 hour 25 minute taste of parts we may never see.

[Disneynature Oceans][]
This documentary takes you through some fascinating images. Some things are a little familiar, but with a little twist. For instance, the film quickly shows footage of the famous sardine run off the coast of South Africa. We've seen it a million times, but this particular footage had …

Aluminum vs. Steel Scuba Cylinders

Most divers never give much thought to what their air cylinder is made of. Even so, it can affect aspects of your dive. Besides, it never hurts to know a little about the equipment you're diving with.


Scuba cylinders
Cylinders are made out of two types of material: steel and aluminum (actually an aluminum alloy). Each have different properties that make it appealing for different types of construction and use.

Steel cylinders are tough, making them resistant to damage. They also tend to support higher capacities, because of their increased strength. The downside to steel is that it can rust if …

Emergency Assistance Plan (free template)

Probably the biggest source of confusion during a rescue diver course is the creation of an emergency assistance plan. Students aren't sure how much or how little to include. They aren't sure they did it right when it doesn't take a long time. This article is meant to clear up these problems.

Emergency assistance plan
First of all, I'm going to say that creating an assistance action plan should not be a terribly difficult exercise, especially in the internet age. There are a few key components that should be included along with a few optional items. Finding this information these days should be …

Identifying Fish Fins

To be able identify and discuss fish, it is helpful to know all the types of fish fins. It makes descriptions much easier, and there really aren't that many. Here are the eight types of fish fins:

  • Dorsal fins are found on the back of the fish. There may be up to three of them. The fish uses this fin for balance in the water and sudden movements.
  • Caudal fins are also known as tail fins. This is what we refer to as the fish's tail.
  • Anal fins are on the ventral (bottom) surface of the fish, behind the anus …

Do Fat People Stay Warmer Underwater?

It is commonly thought that fat people stay warmer in water. If you asked someone "why", you'd probably here a joke about blubber. It's not that simple, however.

In fact, fat does not keep you warmer underwater. It is actually muscle tissue which generates heat that keeps you warmer. Fat can't generate heat. But again, it's not that simple, so low body fat does not mean staying warmer.

Total body mass (muscle and fat) is more important than just proportion of body fat (although a little bit of fat tissue actually does provide a small amount of insulation). It's hard …

Project AWARE Tips For Underwater Photographers

Project AWARE has posted a one-page PDF with 10 tips for underwater photographers.

The tips are definitely "Project AWARE"-style, in that they are meant to remind you that taking pictures comes second in priority after not hurting the aquatic environment.

Here are the 10 tips:

  1. Photograph with care
  2. Dive neutral
  3. Resist temptation
  4. Easy does it
  5. Sharpen your skills
  6. Be informed
  7. Be an AWARE diver
  8. Take only pictures, leave only bubbles
  9. Share your images
  10. Conserve the adventure

Check out the PDF if you're interested and have a few minutes to spare.