Number of dives vs. total bottom time

[bash]

Hi y'all

I value the information stored in my log book: it reminds me how much weight I needed last time I used an aluminium tank, it convinces the dive boat operator to let me dive at deeper sites, it records my first dive with my new regulators and reminds me when they are due for servicing...

but

I have a busy life. I can't put a high priority on time to write up my log book.

So here's my question one:
What information is NEEDED in a log book?

Question two:
What are the 5 most useful pieces of additional information you want to record in your log book (ie assume you've already recorded the stuff you need)?

I'd also be interested to know why you find the information from Q2 useful.

-bash

 

[Dee]

Walter....Yes, Moo sent the link to me when he got it finished. Sure brings back good memories.

Sheesh...I wish I hadn't seen #17! Doesn't moo know how to crop? =;^)

 

[Walter]

NJ Diver, send me an e-mail & I'll reply with the spreadsheet.

Bash, you don't need a logbook at all. Many divers get along just fine without one.

Useful is another story all together. Things I find useful include:

equipment configuration
temperature at a given location on a given date
depth
bottom composition
lessons learned
sketches of the site
marine life encountered
number and type of fossils found
current

Some of these apply to some dives, but not to others. I use these for planning future dives.

Dee, Moo's an engineer, not an artist.

WWW™

 

[Dee]

Bash.....I designed my own log pages so they have what I want on them. At the end of the dive day, it takes less than 10 minutes to record all the pertinent data. A bit more than that when I get caught up in the comments section.

Your questions of what is NEEDED and what is WANTED will vary from person to person, depending on what they use their logbook for. In fact alot of people don't keep one at all. I use mine as a record of my dives, a reference of diving conditions at various places during various times of the year, reference for thermal protection and weights needed. I use it to plan future dives. In the back of my logbook, I also keep a record of dive operators used and contact info for them. I keep emergency numbers for every location, both in and out of the country.

I always have my logbook with me when signing in with a dive op in case they require to see it. But it never goes on a boat.


In my logbook, I need
Date
Location
Dive site
Dive No.

Max. depth
Bottom time
EAN% (if diving Nitrox)
Time in and time out
PSI start and end

Weights
Air and water temps
Tank size and material (steel or alum)
Exposure suit
Visibility


I want...

Today's Dive No. and Trip Dive No. - I may not remember the site but I know it was the 3rd dive from yesterday so it's easier to find if I need info from that dive.
Type of dive...shore, boat, wreck, night, etc.....I keep up with how many of each
Fresh or salt water...this effects my bouyancy
Description of current, if any....help explain my SAC rate on some dives
SAC rate, volumn used and volumn used per minute (this is needed to plan some dives)
Total bottom time.,.to me it's a curiosity
Activity/comments...Where did I see that Whaleshark??? Marine life found, any incident that may have occured, good or bad.
Names of Divemaster and/or boat Captain....I note how well they did their job and I can ask for them next time.
Signature of Instructor if it's a training dive and Cert. No....I need that
Average depth...a better indicator of the overall dive than just the max. depth
Configuration of gear/equipment
Description of site....what kind of bottom (silty?), maybe a sketch for navigation


In addition to this logbook, I also keep it on the internet at IDL.
Internet Dive Log

If something does happen to my physical logbook, I can recover the data from the 'net. It also has lots of features that I use to flesh out details and I can also download my dive computer and watch through it.

In my divemaster logbook, I keep the same data as above as well as a record of who the Instructor is, and the number of students and their names. If there is an incident of any kind in class, it is recorded with the details and action taken. (This is called covering your fanny in case of lawsuits)

I know this looks like it would take a huge binder to keep up with but actually the pages are 5.5 x 8 in a 3-ring cordura binder with zipper.

Is this what you wanted to know? Yes, I'm a bit anal about my logbook!

 

[bash]

Dee, you seem to record the same stuff I've been recording... but I'm thinking of cutting back on the volume of stuff.

For example, when I first started diving I was told to record air pressure in and air pressure out), so that I could calculate my air usage.

It seems to me that air use varies a lot depending on whether I got a rest at the surface before descending, current, temperature, depth, my buddy (ie you use more air if you're with a speedie, and less air if you fluff around a small area), length of deco... and so on.

This variability obscures most of my ability to extrapolate my air use from one dive to the next. By the time I have worked up enough dives to calculate my air use, I'd have developed sufficient experience to predict (without calculation) my air use under most normal conditions. And I wouldn't have enough data to calculate my air use under abnormal conditions.

Consequently, I'm thinking of dropping off the air in/air out history. Naturally I take note in my head of the air-in before my dive for planning purposes, but I shouldn't need a record of it.

It sounds like you have a fair bit of experience in this business of calculating air use. Can you explain how it works (or should I look up a historical thread?) Can you really calculate your air use with accuracy?

cheers
-bash

 

[Puddle Jumper]

Walter,

How true, the day we quit learning would be a sad day for all. I also try to learn something new about this wonderfull sport daily, and as a instructor, most people would be amased just how many new things one can pick up simply by listening to the new comers to the sport, Especially on how they perceive what we have said. Walter you do a splendid job in expressing yourself and in teaching others. Have a great day.

Puddle

 

[CheeseWhiz]

Walter - you mention logging "number & type of fossils found"...does this include my dive buddies?

Bash - I have a table which I use to estimate air consumption at a given depth, based on past in/out psi readings. I've had it for a while and can't remember where I found it, but it seems to be reasonably accurate, at least for my purposes. If you or anyone else is interested in having a look at it, I can try scanning it in and posting it (or e-mailing it if that doesn't work).

 

[Rick Murchison]

Interesting....
When I was first certified, if a logbook was mentioned at all I don't remember it, and there's nothing in my notes about it. And so my first two decades of diving went completely unlogged, other than an occasional comment in other places like letters. When my bride was certified in '90 she brought home a log book as part of the package, and I began keeping a few notes on sites, weighting & such, but didn't start logging every dive until I decided to start teaching diving in '95.
As for using logbooks for scorekeeping - "How many dives you got?" - it is interesting that in aviation the question is always "How many hours you got?" rather than "how many flights?"
The reason is simple - in diving we pay by the dive; in flying we pay by the hour.
In my world of flying neither flights nor hours counted, but rather "How many traps you got?" - or - for us old warhorses, "How many *night* traps you got?" In diving you might ask "How many overhead environment dives you got?"
Rick

 

[Dee]

Bash...I've come across several ways to calculate SAC rates but I confess that I use a SAC calculator program. It gives me cubic foot per minute.

I agree that there are many variables from dive to dive. I keep track of it as a reference. First you have to establish a base SAC rate. A timed 10 minute stationary rate...I knelt on a training platform at 30 ft. Then a timed 10 minute swimming rate at the same depth. By keeping the records from dives with current, work load, etc. I can tell what to expect under certain conditions. I use 3 different sized tanks so knowing my SAC rate I can calculate how long a tank should last me.

For the type of diving I do, it's accurate enough for me. Others with more experience in technical diving can explain it better, I'm sure.

 

[Fishkiller]

I decided to print the profiles downloaded from my dive computer and keep them in a new logbook tha will have more of the information like you all are including beyond the basic