Improving my SAC rate

[sierra23]

Sounds like ya got it together as that is important. Hope this has helped the original question. Time for me to move on to another topic.

 

[tarponchik]

Finally, in shape or out of shape, getting rid of CO2 is compromised with depth. Try to avoid creating it in the first place and you won't have to worry about it.

And how can we avoid creating CO2? Isn't creating CO2 an inevitable consequence of, like, being alive?

 

[Joneill]

And how can we avoid creating CO2? Isn't creating CO2 an inevitable consequence of, like, being alive?

I think he meant to minimize how much is created by keeping chill/zen and moving as little as possible!

 

[The Chairman]

Isn’t there a 6th “D” for currents? Drift = enjoy the ride!

It's a rip-off of the five "Ds" of Dodgeball (the movie). But yeah, drifting is the most fun, if it's not so fast where you can't enjoy the dive.

And how can we avoid creating CO2? Isn't creating CO2 an inevitable consequence of, like, being alive?

I think he meant to minimize how much is created by keeping chill/zen and moving as little as possible!

Asked and answered.

Many people end a dive and need a nap. This could be a function of too much CO2, especially if you have a dull headache, or it could mean you didn't take a long enough safety stop and are enjoying sub-clinical DCS. Every muscle you use creates CO2. Use more muscles and you'll have to offgas more CO2. Use fewer muscles and you'll have less CO2. Remember, CO2 build up in your blood is the main trigger for breathing. Less CO2 means you won't need to breathe as much. Understanding the physics of trim, buoyancy and control as well as the physiology of breathing will enable you to apply those principles when you finally splash. The more you know, the more fun you can have.

 

[hsinhai]

Try to be the first in the water before splashing, not the last, prep early. Otherwise you will be rushing around, stressing and increasing your breathing rate. If your ready first and in the water just chillaxing you can calm down your heart rate & breathing before you submerge.. last in you'll submerge still breathing hard..

Being calm & relaxed makes the biggest difference for me, which is in my control.

 

[NothingClever]

Three things you can do out of water:
1) Yoga - improves relaxation, gives you some control on breathing
2) aerobic gym, you will become less fat, more fit, and capable of prolonged effort.
3) a course of finned swimming, for learning how to use long fins efficiently, if you have access to a swimming pool.

As always, Angelo gives great advice and perspective.

 

[scubadada]

Being super fit is not a way to improve sac rate. Better diving techniques are. Like not chasing the marine life, letting currents carry you rather than diving into currents, and generally dive very slowly and not like some people that think they need to be swimming. Even if I am going slowly in the current I get more time on my dives and also that means more time to get in some good videos or photos. This dive below with a guide I frequently dive with. We planned to do a wreck dive ( this was the 16th dive on the 6th day of back to back diving of 3 dives a day. We decided to just dive to 50 bar rather than time limit. Started with 210 bar on 80 cubic foot tank.

We got our boat captain to drop us over the wreck and then we dove to that, then slowly back up a sandy slope, you can see a brief time at 12 mins where I found two rare sea horses to get photo's of, then slowly up to the reef wall which we followed along.

Total time 93 minute dive. Funny thing was that after we were dropped off the boat went back and picked up an instructor and two AOW students. They completed their one hour dive and had to wait 10 minutes on the boat for us. When we got back aboard the students asked where we were as they we weren't with them when they came out. We said we dropped off before them. The looks on the faces was priceless. You did a 34m wreck dive and then the reef and still have 50 bar after 1.5 hours?

I weigh 135kg so not a light chap. 185cm tall nearing 60 years old. People assume I use a lot of air. I just have 36 years of diving and do around 150 dives a year atm. Off for another 45 dive trip to Bali in two weeks. I tend to do 30 - 50 dives per vacation over 2 - 3 weeks each trip.

You will really improve if you can do multiple dives like I do in a dive vacation.

View attachment 573120

This looks like a dazzling RMV of about 0.26-0.27 cu ft/min or 7.4-7.6 ltr/min

 

[Blackcrusader]

This looks like a dazzling RMV of about 0.26-0.27 cu ft/min or 7.4-7.6 ltr/min

I think it's a SAC of around 8.5 but on some dives I am like in a trance... in the zone where I become a sea creature myself. The DM guide is one of the best DM's I have dived with he is slightly better than I am on dives. We are about the same or within 5 - 10 bar of each other on most long dives. I did the same dive again with the dive center owner and he was down to 60 bar after an hour. Which is decent nonetheless.

As Chairman pointed out there are very good techniques that experienced divers can help less experienced divers with. Sometimes people will dive with me and go damn..... how can I be better on air like you are. I may spend one dive with them getting their trim and buoyancy correct, the next dive just going slow. Even over two days I can help people improve their air consumption by improving their techniques. Also if possible I do dives with the currents which helps. Also some divers will be 2m above the sea bed or away from a reef wall swimming against the current and I am hugging the terrain, using all the little outcrops or coral fans to block the currents. All those little things add up on the dive. I was with one OW diver who had the previous day finished his dives with around 50 bar after 40 minutes with dives no deeper than him touching 20m. He was really sad about it. I asked the dive center owner who is a friend of mine if I could spend a day doing 3 dives with him and we would just follow the DM but at the back of the dive group. I taught him to leave a little bit of water in his mask and to tilt his head to clear any fogginess instead of doing a full mask clear, got him weighted properly for the end of the dive as he was floating up a bit when down near 50 bar. He didn't have a dive computer which was sort of nice.. also had to stop him looking at his gauge every two minutes... So first dive he improves his dive time to 50 mins at 50 bar, second dive he did 60 mins as he now has better trim and isn't thinking too much about his air. On the third dive of the day in the afternoon he really just followed me and I brought him back to the boat with 50 bar. He was like damn, 50 bar again. But he didn't know the dive time. It was 70 minutes. He was really stoked when I showed him the dive time on my computer. All he needed to do was stop mask clearing, putting air in his BCD and then dumping it, stop chasing everything, stop thinking about his air all the time and not look at his gauge so often. He went from being a little anxious to being relaxed.

I taught this Lion Fish how to trim into a current I swear it.

 

[Blackcrusader]

It's a rip-off of the five "Ds" of Dodgeball (the movie). But yeah, drifting is the most fun, if it's not so fast where you can't enjoy the dive.

Many people end a dive and need a nap. This could be a function of too much CO2, especially if you have a dull headache, or it could mean you didn't take a long enough safety stop and are enjoying sub-clinical DCS. Every muscle you use creates CO2. Use more muscles and you'll have to off gas more CO2. Use fewer muscles and you'll have less CO2. Remember, CO2 build up in your blood is the main trigger for breathing. Less CO2 means you won't need to breathe as much. Understanding the physics of trim, buoyancy and control as well as the physiology of breathing will enable you to apply those principles when you finally splash. The more you know, the more fun you can have.

One thing I tend to do for planning my dives is to do the last 15 minutes at 5m or so..... Especially after doing some deeper dives....
On this dive I knew a camera had been dropped by a diver and said I would look for it. I found it. My dive buddy who is an instructor got narced out at 40m and when I turned around to give him the thumbs up I could see he didn't look right in the face. So I went back up and held onto him and we did a nice slow ascent from 40m to 20m which took us 5 minutes. By the time we were there he was fine again. We also did a nice gas off at around 5m for around 15 minutes. Once back on the boat I checked him again and he was clear eyed and fine. He said yup he got narced and he thinks it was because he followed me on a sharp descent. At least he knew what was happening and I knew what was happening. We still ended up doing a 71 minute dive. The camera I found was working as it was in a 60m housing and the power wasn't on. So I took some video and photos from it for the diver. It was a Go Pro.

 

[scubadada]

I think it's a SAC of around 8.5...

I assumed a 93 min dive, an avg depth of 14.2 m or 47 ft, gas consumed 210-50 bar or 3046-725 psi, and a standard AL80 (77.4).

If your SAC was 8.5 psi/ min, that would be a RMV OF O.22 cu ft/min or 6.2 ltr/min. Now, that would be really low. This also assumes an AL80

Maybe I made some incorrect assumptions