Surface Interval

[mccabejc]

Since there really is no "right" amount of surface interval, what do most people shoot for? I know the longer the better, but do most folks shoot for a particular duration before heading down again? I'm wondering if there's a duration that gives you a bigger bang for the buck, or is it a linear absorption? I guess I could look at my tables...

 

[MikeC]

How deep were you? How long were you down? What were you breathing? How many dives in what time frame? How old are you? Are you doing cold water or warm water diving? How much "work" did you do? What are the specs for dive #2 or is it #3?

Also, how long is the boat trip from site 1 to site 2, how long is lunch?

All of the above should be factored in.

 

[Walter]

Exactly, there are many things to consider. You did forget - what is the depth of the next dive? and what is your objective?

 

[String]

Depends on my dive

<20m for first dive i try to extend an hour or more

If first dive is 40m i aim for 3hrs

 

[mccabejc]

How deep were you? How long were you down? What were you breathing? How many dives in what time frame? How old are you? Are you doing cold water or warm water diving? How much "work" did you do? What are the specs for dive #2 or is it #3?

Also, how long is the boat trip from site 1 to site 2, how long is lunch?

All of the above should be factored in.

I hear ya, but assuming you didn't bring your laptop to calculate all that...

My guess is most folks figure something like "unless the dive was really deep, or the computer says otherwise, we'll hang out for an hour or so, get our tanks filled, then go back in". Am I far off?

 

[Rick Inman]

IMy guess is most folks figure something like "unless the dive was really deep, or the computer says otherwise, we'll hang out for an hour or so, get our tanks filled, then go back in". Am I far off?

Actually, by the time we stop yackin' it's time to dive again!

 

[Xanthro]

My guess is most folks figure something like "unless the dive was really deep, or the computer says otherwise, we'll hang out for an hour or so, get our tanks filled, then go back in". Am I far off?

Pretty much, but usually an hour is enough to bring my pressure group down low enough that I don't have to worry about my next dive.

I've turned around shorter, about 40 minutes, but first dive was only 30 minutes, and second dive was shallow.

I've contemplated sitting here with the tables out and seeing exactly how many minutes my minimum time needs to be, but usually it takes longer to fill air, talk, log, get to the next site than a minimum time anyway.

Xanthro

 

[ShakaZulu]

Jim, I take it you don't like the tables. Ok, your Cobra has a dive planning mode where you can enter your intended SI and then it will tell you what your next dive NDL at specified depths will be..........RTFM.

 

[miketsp]

This is a real issue when doing 2 dives at one site well offshore and the boat is really rolling around. So most people would like to get back into the water ASAP before getting sick. In general if the dive is in the range 20m - 35m we start kitting after about 50mins to hit the water after 1:00hr SI. Go sooner & the 2nd dive gets shortened too much.

 

[mccabejc]

Jim, I take it you don't like the tables. Ok, your Cobra has a dive planning mode where you can enter your intended SI and then it will tell you what your next dive NDL at specified depths will be..........RTFM.

Right, but what I was really wondering is if something like this is the case:

"After X minutes of surface interval, staying on the surface any longer than that doesn't give you much incremental bottom time on the next dive".

For example, does, say, the first hour of SI give you the biggest bang for the buck in terms of NDL for then next dive, or is it a linear function, where 20% more SI gives you 20% more NDL.