Tuesday, 24 January 2012

Scuba Gear checklist for your next dive trip

One of the best ways to avoid forgetting important items for a dive trip is to keep a scuba gear checklist. In fact, if you are about to make a trip, make sure to have your scuba dive gear serviced. To enjoy your trip, you need to divide your scuba gear checklist into two groups, the first group pertains to the actual dive, the other is for your time in the boat. 
For your actual dive you want to make sure you have the
following equipment.
  • Mask: This is essential for good visibility underwater.  Remember, goggles will put too much pressure the deeper you go underwater.
  • Snorkel: This is used primarily to conserve the air in your
    tank at the surface.
  • Fins: Try to move 30 feet underwater without a pair of fins and you will appreciate the importance of scuba fins.
  • Booties: For colder environments, dive boots are a must in your inventory of scuba dive gear. They will protect your skin from the cold water.
  • Mitts and Hood: Hoods are extremely important in colder
    climates. They protect your head, which has the potential
    to loose the most body heat underwater.
  • Appropriate wet suit: More useful in moderate to warm waters to protect your body from the elements(i.e.sea urchins).
  • Weight belt and enough weights: To help you stay down deep underwater
  • BCD: Buoyancy Control Device to help you maintain your buoyancy both underwater and at the surface.
  • Regulator: with octopus(alternate second stage), low-pressure inflator hose, and submersible pressure gauge, dry-suit inflator: Regulators allow you to breath the air from your tank at low pressure. One of the more important components of your scuba gear checklist.
  • Tanks(checked and filled): The tank stores the air that you need underwater to survive. There is an instrument that gauges the amount of air left in the tank to help you plan your dive.
  • Dive tables: The further deep you dive, the more you need to be concerned about your decompression levels. Unless you have a dive computer in hand, it is almost mandatory to use dive
    tables to plan your dives for the day.
  • Compass, computer, timer, depth gauge: These are very popular and more commonplace now than ever before. It is easier to keep track of your decompression needs with a dive computer than a dive table. Remember, dive computers come in all types of price ranges.
Incidental accessories like knives, health, collection bad, dive float, dive flag: These accessories, though often over-looked, can play an important role in your safety underwater. The better prepared you are, the more you can enjoy your underwater experience. Any potential need for specialty equipment like lights, cameras: Dive lights are not only useful at night, but also in murky lake waters.
  • Repair kit:
  • First aid and oxygen kit: If you and your friend are diving independently, this is of paramount importance. Do not overlook this.
  • C-card and logbook: This refers to your open water certification card. The logbook keeps an account of the number of dives that you have made.
  • Check list for your time at the boat: These items are not a part of your scuba dive gear checklist, but are useful in any outdoor activity.
  • Hat: To protect you from the sun.
  • Sunscreen: Ditto.
  • Water: You always want to stay as hydrated as possible. Remember, when you are diving in tropical climates, it is best to have a bottle of water with you.
  • Windbreaker: When you are on a boat in the ocean, you sometimes cannot avoid heavy winds. Having a windbreaker can help you avoid the temperature fluctuations of heavy
    winds, especially in non tropical climates.
  • Towels: This comes in handy when you get back on the boat after your dive. Make sure you dry yourself thoroughly.
  • Long-sleeved shirt for protection from the sun: Diving in tropical climates requires some sort of protection from the sun. In addition to being hydrated properly, you should take
    a bottle of sunscreen, as well as long-sleeved shirt. Sunburns can totally mess up your time underwater.
  • Lunch and snacks: Don’t always depend on your dive group to provide you with meals. Quick snacks such as fruit/granola bars and beverages will prevent you from being hungry. Ask beforehand if food will be provided or catered. Otherwise, consider bringing a sandwich if there is a fridge on board.
  • Seasickness medication: Consult your doctor beforehand if you are prone to seasickness and need medication.

The Protection of a Diving Wetsuit


Wetsuits are meant to keep divers warm by giving them thermal protection. There are some important guidelines which a diver should learn regarding the wetsuit he might acquire and use. First of all, it is important to know that they are usually made from neoprene; most of the times open cell neoprene. Besides, when wetsuits have a coating added to the neoprene they are easier to be worn and taken off.
The practice of free diving and scuba diving imply the use of different kinds of wetsuits. While a 5 mm thick wetsuit would be ideal for keeping warm a free diver, a scuba diver would need a 7 mm thick wetsuit to achieve the same results. Besides, while most free diving wetsuits don't have a zipper, most scuba diving wetsuits do come with them.
If you are looking for an open cell neoprene wetsuit, it is important that you have into account the fact that they can be easily damaged. If, for example, you are going to use jewelry under your open cell neoprene wetsuit, this could easily damage it and open it, so you should be very careful with it or try to find another kind of wetsuit instead of it. If you have long finger nails you should be careful as well since you could damage it while putting it on or taking it off.
It is also important to have in mind that free diving wetsuits should fit the diver in order to work well and give him the proper thermal protection. If a free diving wetsuit is loose or too tight it would not give the protection it should and it could even become a problem since it could be an obstacle to the diver's movements.
There also are recommendations on how to maintain and store your wetsuit. In order to store it properly while you are not using it, you should hang your wetsuit up avoiding folding it since that could damage it. Besides this, you should make sure to wash the suit after using it and make sure to wash all salty water off from it.

Wetsuits Choosing the Right Fit for You

Scuba diving is a sport that is enjoyed by people the world round. Scuba diving trips take place everywhere from the Bahamas to the shores of Alaska to Australia, the gear that divers need is as unique as the sport as well as the people who enjoy it.

The use of a wetsuit is as important in scuba diving as an air tank. It is an essential piece of scuba gear. Choosing the appropriate wetsuit, however, depends upon many factors and preferences. For example, where will the dive be taking place? What will the water temperature be? What type of neckline or stitching do you prefer a wetsuit to have?

When buying a wetsuit, the thickness of the material that is needed is the most crucial decision to be made. The thickness of the wetsuit will be the determining factor to your warmth and comfort underwater. Most suits are sold with thicknesses of 3mm or 6mm, these two choices will be sufficient in most temperatures of water where the average dive will take place.

Another choice that needs to be made is the type of wetsuit that you will need. Wetsuits most commonly are found with short legs and sleeves and long legs and sleeves. The choice of which is right for you depends upon where you are diving, the temperature of the water and your personal tolerance level for temperature changes.

The water temperature will help you when making the decision regarding thickness and length of the wetsuit needed. If you are diving in water that is above 85 degrees, a 2 mm short suit is what you would need. However, if the dive is in water that is 60 to 70 degrees, look for a 6-7 mm long suit. The final decision regarding the thickness and type of suit that is best for you rests upon your own body characteristics.

The type of neoprene that the wetsuit is made of is as important as the thickness of it. The neoprene that a suit is made from will have an affect on several aspects of the suit, including the durability, overall look as well as cost of the wetsuit.

There are three types of neoprene used for wetsuits that are worth mentioning here. They are Gas (chemical) blown, skin and titanium. The purchase of a gas blown suit will result in a more expensive, stronger wetsuit. A chemical blown suit will have a softer feel but will tend to wear quicker as a result, this is less expensive.

The most expensive option is to get a suit that is made with Titanium. These wetsuits have the Titanium either as a coating for the inside or as threads that are woven through the suit. The thought behind adding the Titanium to the wetsuit is that it is supposed to keep you warmer by preventing heat from leaving the body while under water, however, some divers are still skeptical about the validity of this claim.

When trying on a wetsuit for size be sure to check that there are not big gaps in the armpits, that the crotch of the suit is snug, the ankles and wrists of the suit need to be snug, not loose or water will get in. Finally, if in order to close the suit, the zipper needs to be held, it is probably too small and needs to be at least one size larger. On the other hand, if it zips easily and isn’t snug, try a smaller size. If you can’t find a wetsuit that fits exactly right, it can and should be altered.

Use these tips along with recommendations from seasoned divers to ensure the right wetsuit for your needs. Enjoy!

Sunday, 15 January 2012

Full List of Excess Baggage Fees and Sports Equipment (Scuba Diving Equipment) Airline Charges across the world!!

A full list of all airlines and the additional charges for sports luggage and excess fee charges: Scuba Diving Equipment Excess Sports Equipment Charges

British Airways
Hold baggage (standard economy fare): One free item; 23kg
Fee for excess baggage: £28 fee for additional bags booked online; £35 at the airport
Carry-on luggage: One item, must be able to lift into overhead locker unaided
Sporting equipment: Free under checked baggage allowance otherwise extra bag charge applies, limit 190cm x 75cm x 65cm
Bmi
Hold baggage (standard economy fare): Unlimited items; total weight limit 20kg
Fee for excess baggage: £10-£22 per kg
Carry-on luggage: One item, must be able to lift into overhead locker unaided
Sporting equipment: £30 per sector, 20kg limit
Bmibaby
Hold baggage (standard economy fare): £13.99-£14.99 per bag each way, total weight limit 22kg
Fee for excess baggage: £11 per kg
Carry-on luggage: One item, 10kg limit
Sporting equipment: £17.99, subject to space
easyJet
Hold baggage (standard economy fare): £11 per bag each way when paid online, total weight limit 20kg
Fee for excess baggage: £10 per kg
Carry-on luggage: One item, must be able to lift into overhead locker unaided
Sporting equipment: up to £50, subject to space
Flybe
Hold baggage (standard economy fare): £12.99 for one bag each way, £42.99 for two, 20kg limit per bag
Fee for excess baggage: £12 per kilo for first three kilos; £15 per kilo for between 4 and 6 kilos extra; £20 per kilo thereafter
Carry-on luggage: One item, 10kg limit
Sporting equipment: £30, subject to space
Jet2
Hold baggage (standard economy fare): £12.99 for one bag each way (22kg limit), £30.98 for two bags (30kg limit), £43.97 for three bags (30kg limit), when booked online
Fee for excess baggage: £10 per kg
Carry-on luggage: One item, 10kg limit, 56x45x25cm
Sporting equipment: £30, 20kg limit
Monarch
Hold baggage (standard economy fare): £9.99 - £15.99 per bag each way, 20kg total limit
Fee for excess baggage: £7.50 per kg
Carry-on luggage: One item, 10kg limit
Sporting equipment: up to £35, 13kg limit
Thomas Cook
Hold baggage (standard economy fare): One free item; 15kg limit
Fee for excess baggage: up to £70 each way for up to 10kg extra
Carry-on luggage: One item, 5kg limit
Sporting equipment: Up to £60, subject to space
Thomson
Hold baggage (standard economy fare): One free item; 20kg limit
Fee for excess baggage: Up to £15 per kilo at the airport, 50 per cent cheaper online
Carry-on luggage: One item, 5kg limit
Sporting equipment: from £15, subject to space
Virgin
Hold baggage (standard economy fare): One free item; 23kg limit
Fee for excess baggage: £32 for additional bags booked online; £40 at the airport
Carry-on luggage: One item, less than 6kg
Sporting equipment: One piece at no extra cost
Aer Lingus
Hold baggage (standard economy fare): Up to £12 per bag each way; 20kg limit
Fee for excess baggage: £6 per kg
Carry-on luggage: One item, 10kg limit
Sporting equipment: Up to £34
Air France
Hold baggage (standard economy fare): One free item, 23kg limit
Fee for excess baggage: £48 for additional allowance, 20 per cent less online
Carry-on luggage: One item, 12kg limit
Sporting equipment: Free under checked baggage allowance otherwise extra bag charge applies.
Alitalia
Hold baggage (standard economy fare): One free item, 23kg limit
Fee for excess baggage: Up to £17 per kg
Carry-on luggage: One item, 5kg limit
Sporting equipment: Up to £25.50
Iberia
Hold baggage (standard economy fare): One free item, 23kg limit
Fee for excess baggage: £51 up to 32kg, £51 for a second bag
Carry-on luggage: One item, 10kg limit
Sporting equipment: Free under checked baggage allowance otherwise extra bag charge applies.
Lufthansa
Hold baggage (standard economy fare): One free item, plus one free ski bag, 20kg limit
Fee for excess baggage: Up to £10 per kg
Carry-on luggage: One item; 8kg limit
Sporting equipment: Free under checked baggage allowance otherwise extra bag charge applies; 20kg limit
KLM
Hold baggage (standard economy fare): One free item, 23kg limit
Fee for excess baggage: £9 per kg online, £13 per kg at the airport
Carry-on luggage: One item, 12kg limit
Sporting equipment: Free under checked baggage allowance otherwise extra bag charge applies.
Ryanair
Hold baggage (standard economy fare): Up to £20 per bag each way; 15kg limit, up to £40 for a second bag
Fee for excess baggage: £20 per kg
Carry-on luggage: One item, 10kg limit
Sporting equipment: Up to £50; 20kg limit
SAS
Hold baggage (standard economy fare): One free item, 20kg limit
Fee for excess baggage: Up to £9.50 per kg
Carry-on luggage: One item, 8kg limit
Sporting equipment: Up to £17
Swiss
Hold baggage (standard economy fare): One free item, 20kg limit
Fee for excess baggage: no information available
Carry-on luggage: One item, 8kg limit
Sporting equipment: Up to £30
TAP Portugal
Hold baggage (standard economy fare): One free item, 20kg limit
Fee for excess baggage: Up to £17 per kg
Carry-on luggage: One item, 8kg limit
Sporting equipment: Up to £42.50
Air Canada
Hold baggage (standard economy fare): One free item; 23kg
Fee for excess baggage: £65 single charge (up to 32kg)
Carry-on luggage: Two items, each less than 10kg (22lb); First item 23cm x 40cm x 55cm; second item 16cm x 33cm x 43cm
Sporting equipment: Second bag charge (£32) applies, with exceptions.
Air New Zealand
Hold baggage (standard economy fare): One free item (20kg) for flights via Hong Kong; two items (46kg total) via Los Angeles
Fee for excess baggage: £33-38 per kg, depending on destination
Carry-on luggage: One item, less than 7kg (15lb); l + w + h = 115cm (45")
Sporting equipment: Second bag charge applies, with exceptions.
American Airlines
Hold baggage (standard economy fare): One free item; 23kg (50lb). Charges apply on domestic flights.
Fee for excess baggage: £33 single charge (up to 32kg)
Carry-on luggage: One item less than 18kg (40lb); l + w + h = 114cm (44")
Sporting equipment: Second bag charge (£33) applies, £66 charge for some items. 
Cathay Pacific
Hold baggage (standard economy fare): One free item (20kg), two free items for flights to/from the Americas.
Fee for excess baggage: 1.5% of adult fare per kilo; £16.50 single charge (up to 32kg) for flights from the Americas.
Carry-on luggage: One item, less than 7kg (15lb); 56cm x 36cm x 23cm
Sporting equipment: Second bag charge applies, with exceptions. 
Continental
Hold baggage (standard economy fare): Max two bags (23kg total), one free item on international flights, charge applies on domestic departures.
Fee for excess baggage: Second bag costs £30.50; charge for excess baggage is £30.50 (up to 32kg).
Carry-on luggage: One item, plus one 'personal item'; 18 kg limit; l + w + h = 115cm
Sporting equipment: Second bag charge applies, with exceptions. 
Delta
Hold baggage (standard economy fare): Max two bags (23kg total), one free item on international flights, charge applies on domestic departures.
Fee for excess baggage: Second bag costs £30.50.
Carry-on luggage: One item, plus one 'personal item'; 18 kg limit; l + w + h = 115cm
Sporting equipment: Second bag charge applies, with exceptions.
Emirates
Hold baggage (standard economy fare): Max two bags (23kg)
Fee for excess baggage: £17 charge for bags weighing 23-32kg.
Carry-on luggage: One item, 7kg and 55cm x 38cm x 20cm limit
Sporting equipment: Standard rules apply, with exceptions.
Japan Airlines
Hold baggage (standard economy fare): two piece, each less than 28kg
Fee for excess baggage: Up to
Carry-on luggage: one item, limit 10kg, 55cm x 40cm x 25cm
Sporting equipment: Standard baggage allowance applies, subject to space.
Qantas
Hold baggage (standard economy fare): To/ from Americas: two bags. All other international flights: no limit on number of pieces but total weight not to exceed 23kg (50lb). Fee for excess baggage: A$35/kg (£21) for long-haul flights
Carry-on luggage: 7kg (15lb) per piece on standard economy tickets: 1 x 115cm (45in) bag or 1 x 185cm (73in)
Sporting equipment: Can be included as part of your checked baggage allowance. Charges will apply for any baggage carried in addition to the free allowance. Buy Additional Baggage Allowance in advance to save on airport excess baggage rates. Subject to space being available. 
Qatar Airways
Hold baggage (standard economy fare): All flights: First bag free, limit 20kg, l + h + w = 158cm, transatlantic flights: two items up to 23kg each, l + h + w = 158cm
Fee for excess baggage: Depends on destination, e.g. Bangkok £38.94 per kilo, Doha £23.58 per kilo.
Carry-on luggage: one item up to 7kg
Sporting equipment: Most weighted with other baggage apart from golf clubs which have a maximum weight limit of 15kg.
Royal Jordanian
Hold baggage (standard economy fare): One item up to 20kg, l + h + w = 158cm
Fee for excess baggage: £102 per item, each way
Carry-on luggage: one item up to 7kg, either a small handbag/briefcase or a suit pack/garment bag
Sporting equipment: some checked items, such as surfboards and bicycles will be charged a fixed handling fee
Singapore Airlines
Hold baggage (standard economy fare): One item, 20kg limit
Fee for excess baggage: Upto £41 charge per kg, depending on destination
Carry-on luggage: one item up to 7kg and l x w x h = 115cm
Sporting equipment: Some checked items will be charged a fixed handling fee. 
Thai Airways
Hold baggage (standard economy fare): Two pieces, 20kg limit
Fee for excess baggage: Charges vary, depending on destination.
Carry-on luggage: One item, max 45cm x 56cm x 25cm and 7kg
Sporting equipment: Standard baggage rules apply.
United Airlines
Hold baggage (standard economy fare): One free bag on flights to/from Europe, 23kg limit, charges apply for domestic flights.
Fee for excess baggage: £30.50 charge for second bag.
Carry-on luggage: One item, plus one 'personal item'; 18 kg limit; l + w + h = 114cm
Sporting equipment: Standard baggage allowance applies.
US Airways
Hold baggage (standard economy fare): First bag (less than 23kg) costs £13.50, Second bag costs £20.50, further bags cost £68 each.
Fee for excess baggage: £30.50 charge for bags 23-32kg
Carry-on luggage: One item, plus one 'personal item'; 18 kg limit; l + w + h = 114cm
Sporting equipment: Standard baggage allowance applies.

PADI Dive Tables PDF Download - Chikarma Diving

PADI Dive Tables - Free Download 

Right Click the above image and select save as to print out full size tables. 

By Chikarma Diving - www.chikarmadiving.com

PADI Recreational Dive Planner Tables - Chikarma Diving

First dive

Using the PADI Recreational Dive Planner tables, let's say you plan on visiting a reef that's 60 feet down. The No Decompression Limits and Group Designation Table, shows that the absolute maximum time you can stay at that depth without having to make a decompression stop is 55 minutes (if you have enough air, that is). It's never a good idea to dive to the limits, so you decide to stay down 35 minutes (which places you in Pressure Group N; more on that later). You do that dive and come back up. Can you now just use that same table, get a fresh tank of air, and go right back down for a second look? No way.

Residual nitrogen after a dive

See, the problem is that while science has determined that it is safe to ascend from 60 feet after 35 minutes -- "safe" meaning that nitrogen gets released at a sufficiently slow rate so as not to pose a danger -- it does NOT mean all the nitrogen that was absorbed into your body down there was released during ascent. Think of the soda bottle example again: even if you leave the bottle cap off, the soda doesn't go all flat immediately. Some of the fizz stays in, and only after a few hours or even a day or two does it go all "flat." Same with the nitrogen in the human body. After you're back up, there's still some nitrogen left in your tissues, and it takes time for that to be released. What that means is that if you dive again, you still have some extra nitrogen in your body, and therefore reach the maximum safe time limit of nitrogen absorption sooner. Which means if you go down to the same depth, you can't stay as long as the first time. And that is what Table 2, the Surface Interval Credit Table of the PADI dive planner is all about. It essentially tells you how much nitrogen leaves your body over time.
That is where the "Pressure Groups" come in. After your first dive you are in a certain Pressure Group, as shown in Table 1. That 35 minute dive to 60 feet put you in Pressure Group N. Table 2 shows what Pressure Group you will be in after a certain "surface interval," i.e. the time between the end of your first dive and the start of your second dive. Obviously, the longer you wait, the more of the extra nitrogen your body absorbed during the first dive gets released.
So what the Dive Planner does is determine how much extra nitrogen is still in your body after a dive, and then convert that into "Residual Nitrogen Time," or "RNT." That sounds intimidating, and they really should come up with a simpler term and explanation. As is, "Residual Nitrogen Time" tells you how much time at a certain depth it would take to absorb the amount of nitrogen you already have in your body from the previous dive, and you can find that in Table 3, the Repetitive Dive Timetable. What does that mean? Well, if the table says your residual nitrogen time is 20 minutes for a given depth, then you can stay at that depth 20 minutes less than on your first dive because, after all, you already absorbed that much nitrogen and it still is in your system.

How to plan for the second dive

So let's see how we use the tables to plan the second dive after our 35 minute stay at 60 feet. We plan on a surface interval of half an hour, and then go see another reef that's 50 feet down. Using the PADI table, we find that the first dive put us into pressure group N. We follow "N" into table 2 and then find the column for a 30 minute surface interval. That would be column I.
So now we flip the table (told you it was a bit cumbersome) and look at column I. Then we look at the cell where column I intersects with the 50 feet row. There will be two numbers: 31 on top (white background) and 49 on the bottom (blue background). The top number is your residual nitrogen time. So on your second dive to 50 feet, you still have as much nitrogen in your system as you'd absorb in 31 minutes down there. The second number, 49, is your adjusted no-decompression limit, the time you cannot exceed on your next dive. In other words, your actual bottom time can be no more than that. Let's say you decide to stay down for only 30 minutes.
So where do you stand after your second dive? Well, You still had enough residual nitrogen in your system as you'd get from a 31 minute dive, and you now added another 30 minutes of actual bottom time on your second dive. So your total bottom time is now 61 minutes. Flip the chart around and look at Table 1. Yikes. At the end of your second dive to 50 feet, you're now in pressure group T.

And a third

But let's say you're still not done after your second dive and you plan a third, again to 50 feet. As stated above, although you only stayed for 30 minutes at 50 feet on the second dive, you need to add the 31 minutes of residual nitrogen you still had in your system, i.e. 31 minutes. So the total nitrogen is as if you'd stayed down there for 61 minutes, making 61 minutes your total bottom time and you are in Group T. If you now plan on waiting an hour and 15 minutes, and then go see that reef at 50 feet again, you find yourself in Pressure Group E. Flip the chart once again so you can see Table 3. Find where column E intersects with the 50 foot depth row and you find that your residual nitrogen time is now 21 minutes and your new adjusted no-decompression limit is now 59 minutes. And so on.

How to back into surface interval time using the dive tables

In real life, reality often interferes with the best laid plans and time is an issue. Let's say you do that first 35 minute 60 foot dive, ending up in Pressure Group N, and then want to see another dive site that's 50 feet down and you'd like to explore for 40 minutes. How long would you have to wait on the surface? Well, start with Table 3, find where the 50 foot row intersects with an adjusted no-decompression time of 40 minutes, and you find it's column L. Flip the card and see where your current Pressure Group, row N,intersects with the Pressure Group you'll be in after that second dive, L. You find that your surface interval needs to be just 9-13 minutes. Just to practice a bit more, assume the second dive goes down to 50 feet again but you'd like to stay for an hour. Now Table 3 shows you're in Pressure Group D. Flip the chart and intersect column D with row N. Oops. Now you have to wait 1:00 to 1:08 hours between dives. See what a big impact the extra bottom time has on surface interval time?

PADI Dive Table "Fine Print"

The PADI recreational dive planner tables have some "fine print" (literally) on the backside. That's important stuff and not to be ignored, ever. Safety stops -- the optional 3-minute safety stop at 15 feet becomes mandatory if you get within three pressure groups of a no-decompression limit, or for any dive deeper than a hundred feet.
Emergency Decompression -- If for some reason you exceed a no decompression limit by up to five minutes, you must make an 8-minute decompression stop at 15 feet, and then not dive for six hours. If the no decompression limit is exceeded by more than five minutes, you must make a 15-minute stop at 15 feet and then not dive for at least 24 hours.
Air travel after dives -- After a single dive, wait 12 hours. After multiple dives, or several days of diving, wait 18 hours. If decompression stops were necessary, wait more than 18 hours.
Altitude diving -- Special procedures are required if you dive in altitudes in excess of 1,000 feet. (You add two PADI pressure groups per 1000 feet, so if you drove from zero up to mountain pass at 8000 feet, it'd be 16 pressure groups once you reach the summit, and you'd be the equivalent of a PADI "P" diver.)
Multiple dive rules -- Anytime the ending pressure group on the PADI table is W or X, all following surface intervals must be at least an hour. Anytime an ending pressure group is Y or Z, all following surface intervals must be three hours.
Cold water dives -- if diving in cold water, add ten feet to the actual depth.

Dive table assumptions

The standard recreational dive planners from all certifying agencies all make pretty much the same assumptions. They are for standard compressed air, not Nitrox or other mixes. They assume you're diving at sea level or in waters no higher than a thousand feet. They assume you descending at about 60 feet a minute, and come up at 30 feet per minute, and slower for the final 15 feet. If your depth or time is between two columns or rows, alway use the greater one. For dives less than the shallowest on the table, use that shallowest one. Always do the deepest dive first, and always dive from deep to shallow. Further, if you dive in very cold water, or do a stressful or strenuous dive, add an additional safety margin. And wait 12 hours til you fly if your total dive time was no more than two hours, 24 hours if more. Any dive within 24 hours is a repetitive dive and must be treated as such.

How to use NAUI Dive Tables - Chikarma Diving


How to use the dive tables

Now what do Dive Tables do? They tell you how long you can stay, maximum, at certain depths and then come straight back up, without any decompression stops.

Examples using NAUI Dive Tables

First dive

You're on a dive boat and ready for diving. Using the NAUI Dive Tables shown to the right, let's say you plan on visiting a reef that's located at a depth of 60 feet. NAUI Table 1, the End-of-Dive Letter Group Table on the upper right of the plastic dive table, shows that the Maximum Dive Time (or MDT) you can stay at that depth without having to make a decompression stop is 55 minutes (if you have enough air, that is).
It's never a good idea to dive to the limits, so you decide to stay down 35 minutes (which places you in Letter Group G, but more on that later).

You do that dive, enjoy the scenery, and then come back up. Can you now just use that same dive table, strap on a fresh tank of air, and go right back down for a second look at that reef? No way.

Residual nitrogen after a dive

See, the problem is that while science has determined that it is safe to ascend from 60 feet after 35 minutes -- "safe" meaning that nitrogen gets released at a sufficiently slow rate so as not to pose a danger -- it does NOT mean ALL the nitrogen that was absorbed into your body down there was released during ascent. Think of the soda bottle example again: even if you leave the bottle cap off, the soda doesn't go all flat immediately. Some of the fizz stays in, and only after a few hours or even a day or two does it go all "flat." Same with the nitrogen in the human body. After you're back up, there's still some nitrogen left in your tissues, and it takes time for that to be released. What that means is that if you dive again, you still have some extra nitrogen in your body, and therefore reach the maximum safe time limit of nitrogen absorption sooner. Which means if you go down to the same depth, you can't stay as long as the first time. And that is what Table 2, the Surface Interval Table, or SIT, of the NAUI Dive Tables is all about. It essentially tells you how much nitrogen leaves your body over the time you spend on the surface, sitting on the deck of the dive boat.
That is where the "Letter Groups" come in. After your first dive you are in a certain Letter Group, as shown in Table 1. That 35 minute dive to 60 feet put you in Letter Group G (you always round up). Table 2 shows what Letter Group you will be in after a certain "surface interval," i.e. the time between the end of your first dive and the start of your second dive. Obviously, the longer you wait, the more of the extra nitrogen your body absorbed during the first dive gets released.

So what the Dive Tables do is determine how much extra nitrogen is still in your body after a dive, and then convert that into "Residual Nitrogen Time," or "RNT." That sounds intimidating, and they really should come up with a simpler term and explanation. As is, "Residual Nitrogen Time" tells you how much time at a certain depth it would take to absorb the amount of nitrogen you already have in your body from the previous dive, and you can find that in Table 3, the Repetitive Dive Timetable. What does that mean? Well, if the table says your residual nitrogen time is 20 minutes for a given depth, then you can stay at that depth 20 minutes less than on your first dive because, after all, you already absorbed that much nitrogen and it still is in your system.

How to plan for the second dive

So let's see how we use the NAUI tables to plan the second dive after our 35 minute stay at 60 feet. We plan on a surface interval of half an hour, and then go see another reef that's 50 feet down. Using the NAUI table, we find that the first dive put us into Letter Group G. We follow "G" down into Table 2 and then find the new Letter Group for a 30 minute surface interval. That would also be Letter Group "G".
So now we follow the Group G row left into Table 3, the Repetitive Dive Timetable. Then we look at the cell where row G intersects with the 50 feet column in Table 3. There will be two numbers: 56 on top (number in blue) and 24 on the bottom (bold number in red). The top number is your residual nitrogen time (RNT). So on your second dive to 50 feet, you still have as much nitrogen in your system as you'd absorb in 56 minutes down there. The second number, 24, is your adjusted maximum dive time (AMDT), the time you cannot exceed on the dive.

In other words, your actual bottom time can be no more than that. Let's say you decide to stay down for only 20 minutes.

So where do you stand after your second dive? Well, You still had enough residual nitrogen in your system as you'd get from a 56 minute dive, and you now added another 20 minutes of actual bottom time on your second dive. So your total bottom time is now 76 minutes. Now go back to Table 1 and see what Letter Group 76 minutes at 50 feet puts you in. Yikes. At the end of your second dive to 50 feet, you're now in Letter Group "J".

And a third

But let's say you're still not done after your second dive and you plan a third, again to 50 feet. As stated above, although you only stayed for 20 minutes at 50 feet on the second dive, you need to add the 56 minutes of residual nitrogen you still had in your system, i.e. 56 minutes. So the total nitrogen is as if you'd stayed down there for 76 minutes, making 76 minutes your Total Nitrogen Time and you are in End-of-Dive Letter Group J.
If you now plan on waiting an hour and 15 minutes, and then go see that reef at 50 feet again, you find yourself in the new Letter Group H. Now move left to Table 3. Find where row H intersects with the 50 foot depth column and you find that your residual nitrogen time is now 66 minutes and your new adjusted no-decompression limit is now 14 minutes. And so on.

How to back into surface interval time using the dive tables

In real life, reality often interferes with the best laid plans and time is an issue. Let's say you do that first 35 minute 60 foot dive, ending up in End-of-Dive Letter Group G, and then want to see another dive site that's 50 feet down and you'd like to explore for 40 minutes. How long would you have to wait on the surface? Well, start with Table 3, find where the 50 foot column intersects with an Adjusted Maximum Dive Time of at least 40 minutes, and you find it's row E. Move right to Surface Interval Table 2 and see where your current Letter Group, column G, intersects with the Letter Group row you'll be in after that second dive, E.
You find that your surface interval needs to be between 1:16 and 1:59 hours. Just to practice a bit more, assume the second dive goes down to 50 feet again but you'd like to stay for an hour. Now Table 3 shows you're in New Group B. Follow row B to the right to Table 2 where it intersects with column G. Oops. Now you have to wait 4:26 to 7:35 hours between dives. See what a big impact the extra bottom time has on surface interval time?

Backside of the NAUI Dive Table

The NAUI Dive Tables have some explanations and additional rules on the backside. That's important stuff and not to be ignored, ever.
Repetitive Dive -- The term "repetitive dive" refers to any dive made less than 24 hours after a prior dive.
Actual Dive Time (ADT) -- By NAUI definition, that is the time from the start of descent to the time you are back up at the surface.
Letter Group -- As explained above, for repetitive dive planning purposes it represents the "Letter Group" of the amount of nitrogen that remains in your body after a dive.
Surface Interval Time (SIT) -- That is the time you spend on the surface, between two dives.
Residual Nitrogen Time (RNT) -- Represents, for repetitive dive planning purposes, the amount of nitrogen remaining in your body from a dive, or dives, made within the prior 24 hours.
Adjusted Maximum Dive Time (AMDT) -- That is how long you can stay at a certain depth in a repetitive dive. It is the depth you could stay there if it were your first dive minus the residual nitrogen time.
Total Nitrogen Time (TNT) -- Add up your actual dive time (ADT) and your residual nitrogen time (RNT). That number of minutes is used to find the letter Group after your next dive.
The NAUI Dive Tables also remind that:
  • Dives to less than 40 feet depth are treated as 40 foot dives
  • Do not ascent faster than 30 feet per minute
  • To maximize dive time, start with the deepest dive, and then make each repetitive dive shallower than the prior one.

What does a Dive Planner do?

As explained in the "Physics" and "Physiology" sections, when we dive, our body tissues absorb nitrogen. In those sections you learned that according to William Henry's law, the amount of gas a liquid can absorb is related to pressure. Since the pressure under water is considerably higher than above water, our body absorbs more nitrogen when diving, and ever more so the deeper we dive. As we come back up, the pressure decreases, the fluids in our body can carry less absorbed gas, and the nitrogen gets expelled from the tissues again.
For a simple, somewhat dramatic, visual explanation of how absorbed gas leaves a liquid as pressure decreases, picture a bottle of carbonated soda that's been shaken a bit. When you unscrew the cap, pressure is suddenly reduced and the soda foams as carbonation is released. That happens because the pressure inside the bottle dropped when you unscrewed the cap. It's even more dramatic when you pop open a can of beer. Shake either a bit and you really see how gases get expelled from a liquid as pressure suddenly drops.
This same thing is happening in your body as you ascend. Much more slowly and much less dramatically, of course. But it's also much more serious. You do NOT want nitrogen rapidly bubbling out of your tissues and clogging up your blood circulation or bubbles getting lodged in other areas. This is why it is essential to slowly and safely release nitrogen as you ascend, and not build up too much in the first place. That is where the dive planners come in. They tell you how long you can dive at certain depths and how long it will take to get rid of all the extra nitrogen in your system.
Recreational dive planners do not actually tell you how much nitrogen is inside your body. They simply tell you how many minutes you can stay, max, at certain depths without having to do decompression stops, something that is not part of recreational diving and that you should never have to do as a recreational diver. The tables have been around for about a hundred years and are all based on data originally developed by the United States Navy. The data is the result of applying the gas laws on the human body, by making certain guesses, developing certain models, and by numerous studies, observations and tests conducted over many years.
All of that led to the "dive tables" that were first used by the Navy, and then, as recreational scuba diving became popular, modified for recreational use. In 1988, Diving Science & Technology introduced the first dive tables for no-decompression recreational diving. You might guess that the recreational dive tables have a significant safety margin built in. Do not take that to mean you should simply use the numbers as loose guidelines. No way. In fact, if anything, be even more conservative when planning your dives than the table data suggests.

Dive Tables Explained -- NAUI and PADI - Chikarma Diving

In this section we explain dive tables and go through specific examples of repetitive dives, using both the PADI and the NAUI tables.
Dive tables are used to determine how long you can safely stay under water at a given depth, both for the initial dive and for subsequent dives.
To many aspiring scuba divers, Dive Tables are scary. It seems inconceivable that they'd ever understand them, let alone become proficient in using them. And truth be told, dive tables -- called "Recreational Dive Planners" by PADI and just "Dive Tables" by NAUI -- do look complicated and intimidating with their tables and charts and unfamiliar terminology.
Even the supposedly friendly PADI recreational dive planner that every student must understand before s/he successfully completes the PADI Open Water Scuba Diver course and gets the certification card contains over a thousand numbers on both sides of a small 5 x 7 inch plastic card.
NAUI uses different dive tables, with all tables being on the same side (see the NAUI table above, and click on it to see a larger copy), but you're still dealing with well over 400 numbers. And there are other formats as well.
What's especially frustrating is that all dive tables do essentially the same thing, just not exactly the same way (and often with surprisingly different results). So the NAUI tables are a bit different from the PADI tables, and they use different definitions and acronyms -- just enough to throw you off. It's like driving a car where the gas is on the left and the brake on the right, and one calls the gas "accelerator" and the other "velocity increasing accentuator". My suggestion is to use and understand one set of tables and stick with them.

Amazing Scuba Diving 2012 Calendar Desktop Wallpaper

Through popular demand here is our new free amazing scuba diving desktop wallpaper for download. Simply right click it and save it to you computer. View the picture and then right click the mouse to select set as background.

Why not take your buddies with you!


We tried to leave our pet dog at home when going Scuba Diving but just does not work. He soon found away around it. 

Saturday, 14 January 2012

Can you drink and scuba dive????


If your going to have a drink then don’t get behind the wheel. Equally important should be the message to everyone with a PADI qualification off on scuba diving holidays to lay of the juice before they head below the waves: An obvious message but one that sometimes is not taken seriously.
However, if part of your holiday by the sea involves scuba diving then you have to take responsibility over your condition before you go swimming with the fishes, or you may find yourself down there for good…For many, the whole concept of a holiday is to go somewhere hot on the coast and pass the time either in the water or at the bar – looking out the window onto a drizzly, cold, grey European winter, who came blame them.
Having any level of alcohol in your system in an alien environment, such as being 50 metres under the sea scuba diving in Malta obviously has some danger. Reaction times are slowed, concentration levels are reduced, the ability to process information correctly, the ability to execute physical tasks and tracking of your own performance are all impaired. Not to mention the fact that your perception, already changed by the alien environment, is seriously altered.
We are not just talking about drinks on the shore or on the boat directly before you get in the water. A heavy night in the discothèque can leave you over the limit and dehydrated the morning after.
Dehydration is considered to be one of the prime causes of decompression illness and alcohol has a direct effect on the kidneys, causing a loss of body fluids. This is especially important on deep dives where problems are much more intensified. It is estimated that 50% of all accidents of people of a drinking age are caused in at least part by excessive alcohol.

Drinking may make the colours of the fish and coral more vivid but your senses, reactions and physical capabilities are all severely lessened putting you – and others – in danger.It is not just your own health that you must consider. On scuba diving holidays your diving is a social sport, and your dive buddy is relying on you for their safety, just as much as you are relying on them for yours. If he is your drinking as well well as dive buddy then maybe have a chat and think about the risks you could be both by running.
So, if you are heading out to into the ocean this winter – or anytime – then firstly I’m very jealous and secondly…
…Don’t Drink and Dive!

Thursday, 5 January 2012

What to expect from Malta!

Malta is a small limestone island in the Mediterranean, not far from Sicily or Tunisia. It has many beaches and it should be noted that some of the shores shelves away rapidly which can offer great diving locations. Diving in Malta is mostly shore-based due to this fact; moderately deep diving is possible without being far from the shelter of the shore. Some boat diving is done around Comino in order to reach some of the wreck dives that are located in isolated locations.
Malta played a significant role in World War II, serving as a base midway between mainland Europe and Northern Africa. The consequence of this was that more bombs were dropped there than were dropped on Birmingham in the UK. The bombing inevitably had its casualties, which now make great wreck dives. One of the wrecks is the HMS Maori, the ship that helped crack the code to the 'unsinkable' Bismark. There are also a many wrecks that have been sunk purposefully to serve as underwater attractions for Malta's tourists.
When diving on the Maltese reefs you will find seagrass beds and an abundance of soft coral. There is a reasonable amount of life on the reefs and although the life is not as prolific as somewhere like the Red Sea, it is impressive nonetheless. You may encounter tuna, jacks, barracuda, octopus, moray eels and seahorses, plus you are guaranteed a healthy selection of smaller reef fish. The erosion of the limestone walls creates many caves and arches that greatly improve the diving experience.
Malta would be an ideal holiday destination for a family that has a member who wishes squeeze in a days diving, or for someone who wants a holiday that is purely devoted to diving. There is diving all over the main island of Malta and also on the smaller islands of Gozo and Comino, so wherever you stay there will be the opportunity to dive. The size of the island also means that all sites could be driven to within a few hours and a ferry service frequently runs between Gozo and Malta. Eating out at one of the hundreds of restaurants is a must as food is cheap, costing only about £10 for two courses and a few drinks and is excellent almost everywhere. If you like the taste of fish as much as looking at them underwater, you will be spoilt for choice with the menu.

Air Malta flies diving equipment for free this Winter

This winter Air Malta will waive all charges related to the carriage of diving equipment on its scheduled flights.
This offer is available until 29 February 2012 and applies to passengers transporting one separate bag containing personal diving equipment up to 32 kilos.
Commenting on this initiative Philip Saunders, Chief Commercial Officer of Air Malta said, “Malta is renowned for its world class dive sites and the scheme to waive the diving equipment charge will allow our passengers the freedom to enjoy the various dive sites on the islands with their own equipment, without additional charges”.
With quality dive sites just a stone’s throw away from each other and with mild sea temperatures during winter, visitors to Malta will be spoilt for choice to explore a variety of underwater worlds in the heart of the Mediterranean.

Why should Divers look at Malta & Gozo?

As well as being only a three-hour flight from the UK, the Republic of Malta is supremely convenient for diving, as many of the best sites are accessible from the shore. In fact, as the island of Malta is smaller than the Isle of Wight, it can be quicker to arrive at a dive site by road than by boat. Meanwhile, Malta’s sister island of Gozo is small enough to get from one side to the other in less than half an hour – including the all-important stop to pick up snacks.

Shore diving can offer flexibility and independence for groups and experienced divers. An advantage of islands the size of Malta is that whatever the wind direction, you can make your way to the leeward side of the island to get in the water. Very rarely are all diving options completely blown out, and shore diving can be done all year round. We took a back-to-basics tour of the Maltese islands, kitting up in car parks and in the back of Transit vans, and have put together some of the best underwater sites that can be visited without a boat.

Car parks are generally close to the entry point, although there are some steep walks that can be pretty tough in full kit. That said, our photographer was carrying an old ankle injury but still managed the climbs down to the water and back. Facilities vary: at sites popular with tourists, such as Dwejra and Wied iz-Zurrieq, there are toilets, cafés and ice-cream vans; at quieter sites such as Reqqa Point on the north coast of Gozo, you’ll find only rocks.

Dive centres can take you on guided shore dives, or will arrange accommodation, transport, air fills and kit hire and give you information on dive sites so you can go and dive at your own pace. One thing to note when shore diving is not to leave valuables in your vehicle: break-ins are not unknown, especially at the quieter sites.

Malta and Gozo are big on scenery, with many wrecks purposely sunk for divers and natural caves, tunnels and swim-throughs to explore. The deep azure colour of the water combined with excellent visibility make this a real draw for divers. You find yourself looking out from caves, tunnels or wrecks in wonder at the rich blue – it’s one of the best things about diving Malta.

Considering that the Mediterranean is notorious for its declining habitats, and that Malta is known more for its scenery than for fish, there was much more marine life than I had expected. I spotted octopus and cuttlefish on several dives, and plenty of colourful corals, anemones and tube worms on the reefs. We saw John Dory in Gozo and even asked our guides to help us track down the famously elusive seahorses.

Why not start your diving experience of Malta & Gozo by checking out dive sites available. There is a great site at Chikarma Diving - Scuba Diving Holidays Malta Gozo which has great information on the small fascinating island of Malta.