Reading dive tables

[Kenney]

Hi guys, I am new to diving but I have come across something that bothers me a little. A lot of people at my work place are certified divers. I have only recently become certified. When I have asked about reading dive tables. The response I get from several is. (you dont need to be able to read a stinking dive table.) One of the guys I may some what understand this because he said he just goes by his dive computer. I was told by another just to stay above 1 atm. and I wouldn't have to worry about it. Computers are great and hopefully I will get one someday but, isn't it still a good idea to understand the dive tables and how to read them. I am also a skydiver and if I don't make a jump within a give amount of time I have to do a checkout dive and cover a few things with an instructor. This doesn't appear to be the case in scuba and I guess some people do not take the Initiative to brush up if they have been out for awhile. I am looking forward to having a lot of great dives but, I may be kind of leary about diving with some of my buddies who do not seem to be concerned with some of the things I thought was important.

Just wanted some other opionions, thanks.

 

[SEMO Scuba]

Although you may not use dive tables much after you own a computer you should know how to use them. Computer diving will get you a lot more dive time with shorter surface intervals. I did quite a bit of practice logging made up dives to help me learn the tables. Keep working at it, the tables will become easy after a while.

 

[stargazer61]

You don't need to use a dive table if you are using a computer instead. You can't use both, as frequently you will find that the table shows you are way over the NDL while your computer shows nitrogen time remaining. This is because the computer is calculating your dive as a multi-level dive and giving you credit for bottom time spent at depths less than the maximum dive depth. The standard tables (as opposed to the wheel) don't do that, they treat your entire bottom time as being at the maximum depth.

Regarding the idea of using neither computer not tables - I guess it can be done with short and shallow dives. But you won't have much idea of how close to the NDL you are until you actually do get bent.

 

[LeadTurn_SD]

You need to be able to read and understand dive tables. Even if you use a computer.

One very important reason is that understanding and being able to use dive tables gives you a better grasp of the calcultions your computer is performing for you, and the relationships between depth, time, and nitrogen loading, and how these factors control no decompression limits.

I use a computer, but carry the dive table in my BC pocket, and know my NDL's for each repetitve dive, just in case the computer dies mid-dive (I always wear an old fashioned dive watch for backup bottom timer, along with an analog depth guage).

Safe Diving!

 

[Teamcasa]

A computer does make it simpler to track your NDL but using the tables helps in planning the next dive in a multi-dive day. It will sometimes give you pause to see that by the tables, your NDL and bottom time is reduced significantly from your actual dive. (Unless you are doing a square profile dive.)

Know the tables, learn how to read and use them. Your dive computer is just another tool, know how to use and read it as well.

 

[NadMat]

Hi kenney, welcome to SB! Where are you located in Texas?

As to tables, many people who have been diving tables a long time have just memorized the NDL limits for 30, 60, and 90' or something along those lines, and dive a rather loose plan which is usually gas limited anyway. So unless they are planning on pushing the tables they rarely pull them out to plan. With lake/quarry diving you have often 'been there, done that' so many times you already know by heart exactly what the limits are.

Diving a computer is great, and can get you more bottom time on repetitive dives over multiple days than diving square table profiles. They also have a cool 'gee-whiz' factor, but you should learn to dive tables anyway, and they serve you fine for most local Texas diving.

 

[diver 85]

I atm.................hmmmm.................guess he's going to surface swim VERY Shallow---@ 2 inches below the surface you're already busting 1 atm.............lol.............these guys are jokes- don't listen to them--unless you want to end up in a deadman's box............good luck, if a 12 y.o. can understand them, any adult can.............

 

[don Francisco]

In my opinion, computers are not a reason to give up using tables. I plan my dives using tables and monitor them with the computer. Usually I get some slack based on the actual depth vs the round numbers on the tables.

One advantage of using and understanding the tables is that give you a better feel for decompression theory, which can serve you well during your dives. By way of analogy, imagine the difference in planning a long auto trip, by pulling out a map and planning your route in advance, vs simply jumping in your car and following the GPS instructions. You'll know the lie of the land, can plan meal stops or side trips, and estimate your time to the destination.

Likewise, if you understand the tables and track your dive, you'll do a better job allocating your bottom time and be better equiped to manage a dive when (notice I said when, not if) a computer dies on you. dF

 

[ucfdiver]

Honestly, for recreational diving, let's say dive 1 is an average of 40ft, and you dropped to 90ft for a minute at some point in that dive. For an average diver, they're going to need to use 90ft for their tables, meaning they should be "bent", since chances are with an average depth of 40ft, they exceeded the NDL for 90ft. For the rest of they day, the tables would be of no use to them.

I think it's good to know tables, but for an average recreational diver, they're either going to have to do one dive a day, or stick to only computers or only tables....Unless there's an agency out there that's currently teaching the use of an average depth in basic open water class?

 

[Blackwood]

One very important reason is that understanding and being able to use dive tables gives you a better grasp of the calcultions your computer is performing for you, and the relationships between depth, time, and nitrogen loading, and how these factors control no decompression limits.

I disagree. I think there is a lot more to be learned about decompression by watching a computer than by looking at a table.