May 2009 >> Archives

Caribbean Diving – No Passport Required

<< to HOME page

The Vandenberg arrives in Key West

The 522 ft. Vandenberg arrived in Key West on April 22nd. She is currently berthed at the Truman Annex in Key West undergoing preparation for her sinking in late May. Once sunk, she will become the second largest artificial reef in the U.S.

Want to witness the sinking? Looe Key Dive Center's dive boat - the Kokomo Cat II- will be on site when the the Vandenberg is sunk five miles offshore from Key West. Be part of this historic event. Call now to reserve your spot. Trip price is $125.00 and includes food and drinks. 1-800-942-5397

Latest info on the Vandenberg.

Get ready to dive the Vandenberg

The depth of the Vandenberg will range from 40 feet at the top of the superstructure to 140 feet at the bottom of the hull. Need a dive refresher? Ready to get your Advanced Open Water certification? Want to extend your bottom time by diving with Enriched Air Nitrox? Call our shop 1-800-942-5397 or e-mail us to schedule your class today!

 

FIRST ANNUAL
Looe Key Dive Center
Underwater Easter Egg Hunt a SUCCESS!

The Easter Bunny visited Looe Key Reef on April 12th and left Easter eggs for 21 lucky divers and snorkelers. Everyone on the trip won a prize. One snorkeler and one diver won a FREE trip on the Kokomo Cat II.

Join us next year for more fun and PRIZES!

Upcoming Fun ALERT

• Underwater Music Festival July 11th. Come celebrate the 25th Silver Anniversary of this unique event which takes place right on Looe Key Reef.
• Lobster sport mini-season July 29th - 30th

Turning old regs into NEW
Do you have an old (pre-2000) Dacor regulator? Want to turn it into a new Mares regulator? Trade in your old Dacor and you'll get a brand new Mares Prestige 12 for $200.00 (MSRP $375.00) or a brand new Mares Voltrex 22 for $300.00 (MSRP $600.00).

Gear Miester answers your gear questions...

Underwater life support

Last month we talked about our personal diving life support system - the regulator - starting with the general operation of the first stage. This month, we’ll follow the hose down to the so-called "second stage."

 

2nd in Name Only The purpose of the second stage is two-fold:  reduce the air pressure coming from your first stage to just a few psi above the surrounding water pressure and – this is especially important! - give you something to breathe from. 

The general concept of the second stage regulator is quite simple. When the diver inhales, it creates a vacuum in the second stage housing that pulls down a flexible rubber or silicon diaphragm. That diaphragm then pushes against a spring-tensioned demand lever, opening a valve that allows air to pass through the housing and into the divers’ mouth. When the diver stops inhaling, the diaphragm returns to its original position, allowing the demand lever to rise and close the inhalation valve.

The spring tension on the demand lever can be manually overridden by pushing the purge button on the front of the second stage. (By pushing the purge button, you are using direct force to push the diaphragm rather than using the vacuum “pull” of inhalation.) The purge button is real handy for clearing water from the second stage before taking that first breath.

Finally, when the diver exhales, the exhaled breath passes back into the second stage housing and forces open a simple silicon or rubber one-way flapper diaphragm so that it can exit through the exhaust ports.

Let’s look at some of these areas in more detail plus some of the fancy things that can make the second stage operate better.

Bite me

One of the most overlooked things that a diver can adjust to make their regulator “perform” better is the mouthpiece. The basic mouthpiece is simply a piece of rubber or silicon that the diver clamps between their teeth to keep the second stage in their mouth. Obviously, this can become tiring,  causing jaw fatigue and headaches. There are a variety of different designs and sizes that all purport to solve the problem. You’ll just have to try a few out until you find the one that works for you. There are three areas on your mouthpiece that you need to inspect before each dive. Check the overall condition for any holes, especially where the rubber falls over the hard plastic of the housing. Then check the tie strap that keeps the mouthpiece on the housing. And finally, check that the bite tabs haven’t been bitten through.

Breath easy

Many regulators are designed to create a "venturi effect" when the inhalation valve opens. This increased air flow of the venturi creates its own vacuum in the second stage housing which keeps the diaphragm pulled down, the demand lever depressed, and the inhalation valve open all on its own. Basically, once the diver begins receiving air, the air flows to him without any additional effort. The downside – when jumping into the water, the purge button can be momentarily depressed by the splash and the second stage may start “free flowing.” This can be mildly annoying and a waste of air.

So, this led to another enhancement commonly known as a “dive-predive” adjustment. In the “predive” position, a flap inside the second stage housing disturbs the airflow preventing the venturi from forming. In the “dive” position, the flap rotates out of the way and doesn’t disturb the airflow. Problem solved.

Another adjustment, especially on mid to high end regulators, allows the user to adjust the spring tension on the demand lever. This can be a useful feature when swimming directly into a strong current which  can depress the purge button enough to override the spring tension on the demand lever and cause air to flow even when the diver is not inhaling. If you find yourself diving into currents, this is a nice feature to have.

If you don’t have these features, does that mean that you have a low end regulator? Absolutely not! Several manufactures have designed these functions right into the normal operation of their second stages - the diver needs to make no adjustments to enhance the regulator performance.

It’s exhausting

When you exhale, those bubbles have to go somewhere (unless you’re on a closed circuit re-breather!) It would be really annoying if all those bubbles passed directly in front of your mask every time you exhaled. The purpose of the exhaust ports on the back side of the second stage is to guide those exhaled bubbles away from the front of your mask. But port size matters for optimum performance. Too big and  it creates excess drag. Too small, and the bubbles get in the way. The only way to find out is to test out the regulator.

Position matters
The exhaust ports must be oriented down or the regulator will breathe “wet”. You may have noticed this a little bit when standing on your head to look under a ledge. This is important to remember when you share air with another diver. Take the extra second to properly orient the second stage of your alternate with the exhaust ports down, so that a bad situation doesn’t become worse.

One regulator design that eliminates this problem is the side-exhaust. Rather than having the exhaust ports on the bottom, a single port is placed at one side of the second stage allowing it to be used in any position.

Back-ups

Your alternate second stage works exactly like a primary second stage. It should be conspicuously marked, usually yellow on a yellow hose, so that it’s easy to find in an out of air emergency. Also, the hose is usually longer than the primary hose to allow easier use when sharing air. And don’t forget to keep it attached in the triangle formed by your chin and bottom of your ribcage!  

Instructor Tip: There are typically only three reasons that a regulator will breathe “wet” – there’s a hole in the mouthpiece, the demand diaphragm is dislodged or has a hole in it, or the exhaust diaphragm is dislodged or has a hole in it.

Next month...
we’ll look at the other hoses on our regulator and talk about how to take care of our life support system.

 

Editor's note: The PADI May Specialty is actually Drysuit Diver. But - hey! - we don't need drysuits here in the Keys. So instead, how about....

Enriched Air Diver

The PADI Enriched Air Diver course is PADI’s most popular specialty scuba diving course, and it’s easy to see why. Scuba diving with enriched air nitrox gives you more no decompression dive time. This means more time underwater, especially on repetitive scuba dives.

What You Learn

• Techniques for getting more dive time by using enriched air nitrox
• Enriched air scuba diving equipment considerations
• Enriched air considerations, including managing oxygen exposure, how to tell what’s in your scuba tank and how to set your  dive computer

Prerequisites

• Be 15 years or older
• Have a PADI  Open Water Divercertification (or have a qualifying certification from another organization)

The Learning Materials You Need

The Enriched Air Diver crewpak includes required materials to complete PADI’s Enriched Air Diver specialty. The Enriched Air Diver Manual covers the procedures for diving with Enriched Air (up to 40%) and the Enriched Air Diving video on DVD demonstrates step-by-step how to plan a dive using multiple dive tables. The crewpak also includes the 32%, 36% and the DSAT Oxygen Exposure tables. NOTE: you will also need the PADI Recreational Dive Planner AIR tables

More info at PADI.com

Schedule your class now! Call Looe Key Dive Center 1-800-942-5397
or contact us by e-mail

Have you seen this fish??

Beautiful but deadly, the lionfish is an invasive exotic species native to the Indo-Pacific region. It is being found in increasing numbers along the east coast of the United States as well as the Caribbean. The red lionfish (Pterois volitans) is a predatory fish with few natural enemies that devours smaller indigenous reef fish at an alarming rate. It also poses a threat to divers and fishermen - the fins are tipped with venomous spines that inflict a painful sting.
So far, we have not seen the red lionfish on Looe Key reef. It has, however, been spotted off Key Largo. What can you do?

If you see this fish, report it
More info about lionfish here

 

 

 

Looe Key Fish of the Month
Nurse Shark, Ginglymostoma cirratum

The Nurse Shark is one of the most common sharks seen around Looe Key. Ours are usually brownish and 5 to 6 feet (1.5m to 2m), although they can range in color from dark gray to yellow-tan, and grow as large as 14 feet (5m). They are easily distinguished from other sharks by having a small mouth with two barbells on the upper lip and two nearly equally sized dorsal fins set far back. Their diet consists mainly of crustaceans. You will find them resting under and behind ledges out of the current.