Author Box
Articles Categories
All Categories
Articles Resources

Why Altitude Corrections for Scuba Diving?

February 06, 2012 | Comments: 0 | Views: 121

Why Altitude Corrections for Scuba Diving? OK, when we ascend to an altitude where the air is less dense, the water is fresh and less dense than salt water. Why do we need to make corrections to the dive tables to dive at altitude?

Actually, there are several reasons. First the air is less dense. If you remember your basic scuba class (assuming they taught you about dive tables) Haldane stated that the less pressure exerted by the surrounding atmosphere, the less dissolved gas your body could hold without creating bubbles in your bloodstream.

Also if you are diving with a standard gauge instead of a modern dive computer, you gauge lies! Really it's true. If your gauge didn't have a peg to stop the needle from going below zero, it would read a minus amount. How much? Approximately minus one foot for each 1000 feet in altitude. Also the gauge (really a pressure gauge calibrated in feet) won't register the depth correctly. You are diving in fresh water (34 feet=14.7psi or 1 atmosphere). The gauge, as manufactured, is a salt water gauge. (33 fee =14.7psi or 1 atmosphere).

You have a problem with arrival at altitude also. When you ascend to an altitude from sea level you are traveling to a lesser atmosphere. If you remember Henry's Law, that means less pressure on your body and the liquid in it, therefore less dissolved gas remaining in your bloodstream.

We still haven't addressed the major player in the need for altitude corrections. When you make a dive at altitude and come back to the surface, you are ascending to a less dense atmosphere than the dive tables to track. Some divers have a hard time getting their heads around this fact. Let me repeat this, you are ascending to a less dense atmosphere than the dive tables track. This is like making dives at sea level and then going up in an airplane!

One more thing, if you need to ascend to a higher altitude to go over a mountain pass to get home, exercise caution. You need to off-gas enough so that you don't get bent by going over the summit. Divers have gotten bent (Decompression Sickness) by diving at sea level and then going over the 'Grape Vine' in the Southern California area on the way home!

Ok now you know the problem, what do we do about it? There are several ways. One dive with a modern dive computer that calculates dives at altitude. It also accounts for ascending to altitude and going home and ascending to a higher altitude.

If you are diving with a standard gauge, there are several methods you can use to make corrections to the dive tables. One method is to do several corrections (gauge correction, fresh water correction & finally corrections to compensate for coming up to a reduced atmosphere after the dive).

A better way is to use a table designed to make all these changes in one simple step. For example, the tables referenced in my biography

Different agencies (SDI and others like Padi) have different procedures for altitude corrections to their tables and you should familiarize yourself with them.

Why Altitude Corrections for Scuba Diving? OK, when we ascend to an altitude where the air is less dense, the water is fresh and less dense than salt water. Why do we need to make corrections to the dive tables to dive at altitude? Dave has been a Scuba Instructor since 1984. He holds certification in NAUI, HSA, SSI & SDI. He is the inventor of a High Altitude Calculator http://www.hsdivers.com/HSDstore and High Altitude Tables He is the co-author (with Dr. Bruce Wenkie) of an article on Altitude Diving published in the Best of Sources by NAUI. He teaches at High Sierra Divers http://www.hsdivers.com

Source: EzineArticles
Was this Helpful ?

 
0
 
0
 
Rate this Article
 vote(s)
Feedback
Print
Re-Publish

Article Tags:

Dive Tables

,

Altitude Corrections

,

High Sierra Divers

,

High Sierra Scuba Diving

,

Usn Dive Tables

,

Scuba

LED boat trailer lights are designed to offer high-power output and low-power consumption for ultra-bright and reliable illumination; they are sealed to resist UV-radiation, corrosion, and water

By: Simon Liva l Recreation & Sports > Boating l December 12, 2012 lViews: 274

All these scooters are highly durable as they have been made using qualitative materials. They are ideal for extreme tricks, jumps and stunts for youngsters and are extremely light in weight. All

By: Simon Liva l Recreation & Sports > Extreme l November 24, 2012 lViews: 413

The interest in BMXing has grown massively over the past few years. With BMX hitting its peak in the 80's with freestyle riders, the sport has never looked back. Even more impressively BMX racing is

By: Alan Trotter l Recreation & Sports > Cycling l October 24, 2012 lViews: 452

Mountain biking has grown vastly over the years from simple, open entry competitions to global world cup and olympic events. There are still local enthusiasts and the sport has a dedicated following.

By: Philip Loughran l Recreation & Sports > Mountain Biking l July 10, 2012 lViews: 248

It's unfortunate but true that although summer holidays such as the 4th of July and Labor Day offer some of the best opportunities for families to get out and enjoy some quality time together, with

By: Dexter Luck l Recreation & Sports > Boating l July 10, 2012 lViews: 585

The term "Klunker" that for years became synonymous with heavy, clumsy machines, was actually the model of bike made by the Schwinn company that had something to do with the origins of freestyle

By: John D Meyers l Recreation & Sports > Mountain Biking l July 10, 2012 lViews: 270

Personal Gear such as masks, snorkels, fins, boots etc are important for safe and hassle-free scuba diving. Quality personal gear improves our dive experience immensely.

By: Daniel Decostal Recreation & Sports > Scuba Divingl July 05, 2012 lViews: 178

Numerous people who enjoy scuba diving and snorkeling decide on their vacation destinations with their hobby in mind. Some of the top holiday destinations for scuba diving and snorkeling are the

By: Owen Jonesl Recreation & Sports > Scuba Divingl July 02, 2012 lViews: 189

You are reading this article, therefore you, like so many others, have become intrigued by the wonderful world of open water scuba diving. The world of scuba diving can seem all too complex at the

By: Duncan Marksl Recreation & Sports > Scuba Divingl June 29, 2012 lViews: 208

Here are 9 snorkeling tips to help maximize the fun. In this article you can find tips ranging from strap position to tips on swimming technique and a few in between.

By: Bradley R Wilsonl Recreation & Sports > Scuba Divingl June 26, 2012 lViews: 175

If one takes scuba diving as a recreational activity, he or she must be aware of different interesting and fun facts of the activity. This will help the person to have a more enjoyable time in

By: Daniel Decostal Recreation & Sports > Scuba Divingl June 21, 2012 lViews: 169

Scuba diving is a popular activity for families who are on holiday in tropical areas. It is a wonderful experience since you get to see the wonders of underwater which you would never see anywhere

By: Sara H Shepardl Recreation & Sports > Scuba Divingl June 05, 2012 lViews: 186

Good dive gloves are not cheap. If you indulge in activities like lobster hunting or gold hunting they don't hold up very well. The finger tips wear out, become riddled with holes and lose their

By: Dave Alan Albrightl Recreation & Sports > Scuba Divingl February 14, 2012 lViews: 130

Does it make sense to try to cram a little knowledge in a short time just so you can get certified to take part in a potentially dangerous sport? Don't take a quickie Scuba course.

By: Dave Alan Albrightl Recreation & Sports > Scuba Divingl February 05, 2012 lViews: 113