Depth averaging tables.

[Eric Sedletzky]

comparing post #1 to post #29, both from you...... You talk in circles......

You mean this from post #1 ?
"I know this could get very controversial and heated, it seems all table/computer discussion do, but lets look at this from a historical perspective and not something to be considered now.
We have great computers now that do this much much better"

Where is the inconsistency?

 

[tursiops]

In addition to not needing batteries, the Wheel gives one big advantage over most (not all) dive computers.....you can plan a dive after a designated SI (as you can do with all tables). Most dive computers in "plan mode" just tell you your N2 status at that moment....not what it might be in an hour or two. So if you are planning a multilevel dive, your choice is the Wheel, a Petrel, or....?

 

[Eric Sedletzky]

In addition to not needing batteries, the Wheel gives one big advantage over most (not all) dive computers.....you can plan a dive after a designated SI (as you can do with all tables). Most dive computers in "plan mode" just tell you your N2 status at that moment....not what it might be in an hour or two. So if you are planning a multilevel dive, your choice is the Wheel, a Petrel, or....?

But then what if on your next dive you choose a new unexplored spot and have no idea what to plan for?

 

[rhwestfall]

Wheel is a great "in the ballpark" tool! I was taught using the USN tables (paper set in the New Science of Skin and SCUBA Diving), and did not have a "field set" of plastic ones. Though not being PADI trained (YMCA), I immediately purchased and used the Wheel exclusively for probably almost 10 years. Even once I got a PDC, it was a sanity check, as well as the above "what if" planning tool.

I still occasionally use it today, and the looks alone are worth it.

 

[DiveNav]

...... the Wheel gives one big advantage over most (not all) dive computers.....you can plan a dive after a designated SI ....... So if you are planning a multilevel dive, your choice is the Wheel, a Petrel, or....?

...... a smartphone / tablet with our divePAL app

 

[rhwestfall]

But then what if on your next dive you choose a new unexplored spot and have no idea what to plan for?

Wouldn't you run a series of times to specific depth increments on the table so you have at least a rudimentary "plan" and can also have some idea of gas needs?????

 

[Storker]

But then what if on your next dive you choose a new unexplored spot and have no idea what to plan for?

Didn't you say that your boat has a depth finder?

Don't you cross over the site a couple of times watching the finder to get an idea of the bottom profile before jumping in on a new site? Or do you seriously just drop the anchor (even at that point, even a half-capable boat owner ought to have an idea of whether they have 10m or 50m under their keel) and jump in without a clue about how deep it is and how the bottom looks like?

 

[tursiops]

But then what if on your next dive you choose a new unexplored spot and have no idea what to plan for?

You are just being silly now. Other than preparing contingency plans and boundary conditions ("I'll go no deeper than 80 feet and no longer than 30 mins"), you are in Donald Rumsfeld territiry. There are known unknowns and unknown unknowns....

 

[Eric Sedletzky]

Didn't you say that your boat has a depth finder?

Don't you cross over the site a couple of times watching the finder to get an idea of the bottom profile before jumping in on a new site? Or do you seriously just drop the anchor (even at that point, even a half-capable boat owner ought to have an idea of whether they have 10m or 50m under their keel) and jump in without a clue about how deep it is and how the bottom looks like?

Cruising a site that is that structured can be very tedious and take a while to understand the terrain, which we do. But a depth sounder only tells you part of the story, especially when you approach a site for the first time. Many of these sites are out in open ocean with swells. Trying to navigate a site and pay attention to kelp masses, pinnacle tops that may show themselves during the bottom low point of a swell, and the rest of it we do the best we can. If we can make a couple passes over the ridge to get an idea we figure we're doing pretty good. The rest of it we have to get under to see what it is, and many times to our surprise it's way different than what we were expecting from the sonar readings. Most of the time we're looking for somewhere to anchor that's far enough away from a pinnacle to be safe yet shallow enough to not have to drop too deep to the anchor. I always follow the line down and check the anchor, always.

---------- Post added December 14th, 2015 at 09:37 PM ----------

You are just being silly now. Other than preparing contingency plans and boundary conditions ("I'll go no deeper than 80 feet and no longer than 30 mins"), you are in Donald Rumsfeld territiry. There are known unknowns and unknown unknowns....

I just make my life easy and use a computer (actually two now). Greatest tool ever for exploring the known unknown, and even the unknown unknowns.

 

[Nemrod]

No, I never averaged by I am able to compute multilevel on the fly. Or at least I used to be able to, I had the tables memorized, completely. N