Relying on a computer for surface intervals

If you're in blue water it's nice to know how deep you are.

A freediving computer is a major upgrade in the safety department. I can see your point, but a F.C. is not a sustitution for awareness, experience and common sense. Instead is an aid to help you up to set personal limits. In that case surface time will tell you that current is so strong, that there´s no point to push the envelope if you are tired to fight the stream after 10 long minutes. I would never dive again without one.

Dan,

You're reasoning makes all the sense in the world. It really is one of those items that is a "nice to have" rather than "need to have". Of course, how you feel prior to a dive should dictate if you should descend or not. However, there are times that I'll be diving deep for me, perhaps depths over 70-75'. I will ascend after good dive with ample breath left over and have a surface interval within one minute and I feel like going down again. In these instances where I'm spending an average of 1:15-1:30 below, I should be likely spending at least twice that on the surface. The watch helps me keep it in perspective that even though I feel I may be ready to go down again after a minute on the surface, it will keep me true to the ratio I'd like to maintain. It also provides some sort of rythm or cadence during breathups on the surface. I can explain it in other ways, but it just is a great tool to have and like others have stated before, after you get used to diving with one, you sort of feel "naked" without it.

I don't think a gauge is necessary for spearfishing but it is useful and fun. If you have the computer interface cable you can download the days dives and analyze the history. It tells you how many dives you did, how deep, time of dive, ascent and descent rate bottom time, etc. On pathetic days; we will see that we did 50 dives and didn't even see a fish :confused1: or you can track exactly at what depth the fish were, the water temp, time of day it was..
For analytical type personalities; this is an enjoyable thing to have to record all this info. You can also evaluate your dive skills and conditioning.

Like Rolo said, I use it to make sure I maintain a minimum surface interval, not as an indicator on when to dive. At least double the dive time for less than 80', and 8:00 for more than 80'. I always felt "antsy" on deeper spots waiting 8:00, but I recently went diving with someone that's been bent multiple times while freediving. That helps put the surface interval into perspective.

Quote from smilinmatt

Like Rolo said, I use it to make sure I maintain a minimum surface interval, not as an indicator on when to dive. At least double the dive time for less than 80', and 8:00 for more than 80'. I always felt "antsy" on deeper spots waiting 8:00, but I recently went diving with someone that's been bent multiple times while freediving. That helps put the surface interval into perspective.

"bent" really? Are you sure they didn't just have a squeeze or edema? It is not very common to get any sort of dcs when doing shallow dives( less than 100ft) no matter what the interval is when freediving. You may feel the co2 build up ( hypercapnia) but you shouldn't be getting any bubbles . The risk for repeated dives with inadequate breathe-up is more often black-out from over exertion but maybe some people do get bent- I just haven't seen it.
We've been ultra-sound tested by a researcher from DAN after numerous dives and no one showed any signs of bubbles.Of course, International Freediving( AIDA) has guidelines for deeper dives ( 100m +) which are much more vulnerable to problems.
You are right to double your surface time-always a good idea for a full recovery before doing another dive.

In 8 mins you will be 1 mile away

I generally double my bottom time in the 0 to 60 stuff just to maintain a relaxed rythm. When I start pushing in current I may do double plus 1 minute before I begin my breath up cycle. In deeper water I always do double plus a minute.
For me the watch is a must have piece of saftey equipment. I dove without one for years but consider myself lucky that I did not SWB. If you use the watch to off gas at the surface and then dive when you feel good I think you will be a lot safer. Just saying

The Freediving computer is just like the microwave oven, you don´t really need it until you realize that now you can´t live without one ..

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"bent" really? Are you sure they didn't just have a squeeze or edema?

I wasn't diving with him when either occurred, but he spent two tours in the chamber. When I took FII, Martin S. said that the most likely people to suffer DCS were the ones just learning to freedive. It's good to hear about your testing. During red snapper season, most of my dives are right around the 80' mark, and I tend to waiver between a double bottom time and 8:00 (I usually take my time taking fish to the boat to make sure I've spent some time up top).

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In 8 mins you will be 1 mile away

We're lucky over here that we generally don't deal with current. The only unlucky part is usually over here our visibility is so bad that if you drift 20' on your surface interval, you lose the ledge.

I freedive with the Aeris F10. I think you'll find most people who have taken a freedive course will use a computer or at least a watch. They train you to push your physical limits and understand where your boundries are via static and dynamic apnea. The watch then always you to stay within those boundries while spearfishing. The Aeris takes the guess work out of depth, dive time, number of dives, and surface interval so you can be most productive with your time in the water. I feel I'm able to safely maximize my dives with the aid of the Aeris.

for me, the dive watch is like the angel on your shoulder, it can be listened to as a way to help me or it can be ignored.

I have never looked at my watch and "felt" like I was still not ready to dive when the watch would have said to dive....i shoot for 3x down on my intervals on any dive over 40 seconds...if I am just dropping to retrieve a fish or spotting for bugs i go up and down more.

but I often will look at my watch when I feel ready to dive and it has not been long enough....these are the times I am glad to have the watch.

I also like to review my last few dives and check the temp etc during a surface interval so I can seee how my numbers are compared to how I'm feeling that day.

it is funny because I am very hard on myself...if I am feeling like I am having a shitty day then I check the watch and it is usually 45 -75 second total dives, which I feel is quite good for my skill level

i dont push myself and the watch is another tool to make sure I stay in the safe range of my abilities

+ 1 for everything LB said.

I'm very new at this compared to most here, but I find the watch helps me reconcile what I think I feel, to what actually happens. For example, on my last dive, I was experimenting with swimming around to cover more bottom, vs. just lying still and seeing if the fish would come to me. With the watch as a timer, I could easily see how much longer I was able to stay down comfortably if I just stayed in one place and conserved my energy.

The timer also helps me monitor myself throughout the day. I know that it will take me a little while to warm up, and the timer helps me note my progress as my dives get a little longer. Later in the day, I can tell when I am getting cold or fatiged, and my times fall off or it takes me longer at the surface to feel rested.

And because I'm new, the watch sometimes gives me a shot of confidence. Frustration can be a downward spiral, and sometimes when I surface aggravated after what felt like a short dive, I will see that I was actually down longer than I thought. No frustration = more relaxed = better diving.

Maybe I'll use it less as I gain experience, but I have found it to be a very useful learning tool.

Sorry if that's a bit of a derail, as it's a little off the topic of surface intervals.

45ft or less - go down right away

70ft. I go down when i feel good. Usually 1:30 to 2 mins

80ft or more, i do about 2:30 to 3:00

but sometimes coming off the boat, there is no breathup.

Surface time is supposed to be 2x dive time to avoid "Taravana", which is bend due to freediving. It happens when you dive deep and at a high pace.

When I was younger and stronger, I felt kind of "strange" several times after paticularly deep spearfishing days.

The functions I use most are: Of course dept, which I use when diving new (deep) spots, dive time, which I see when doing aspettos in the bottom and surface time, which I monitor always.

you are not relying on the computer for your surface interval its just keeping track of it for you automatically i have a d3 you dont have to set or do anything to use it (i dont even have the time set) just get in the water and it turns on ,when you dive it shows the dive time in the middle and depth below that ,and when you surface it shows surface time in the middle with depth and time below it. when i started using it i found i "felt" like i was ready for the next dive within 20 sec of surfacing ,now i wait about equal my dive time for normal dives under 60f and 2min and a little longer on deeper dives. i can do that pace for hours without feeling out of breath
phil

phil just stated, in a more articulate way, exactly what I like about the watch