Surface interval

[H2Andy]

the ten minute thing is due to computer issues. i am not aware of a minimum
surface interval other than nitrox dives (1 hour)

the PADI tables allow shorter surface intervals, for example, 8 minutes to go from
pressure group N to M, or 6 minutes from T to S after surfacing.

nitrox diving has a minimum surface interval recommendation of 1 hour. i would
appreciate a link to this 10-minute rule thing

if you floated on the surface between your dives, your instructor did you a disservice.

why exactly?

 

[PADI Knight]

Not sure why it matters though, practically speaking. Are you trying to see how many dives you can do just as table practice, or planning on diving that way?

Yeah just trying to figure how many dives we can get it looking at the table. Figuring with the computers we'd have plenty more bottom time than the table would permit anyway since we won't be doing square dives. Going to be at Ginne Springs until we get tired or they throw us out. Certainly don't plan on being in the water the entire time. Hey have to eat and use the BR somtime plus refill tanks get warm etc. The DP looked really strange when I started counting up the time in and the time out. Which got me thinking and like I said watch out might hurt myself.

 

[Walter]

i would appreciate a link to this 10-minute rule thing

It's based on dive tables. If you have a surface interval of less than 10 minutes, you add the bottom times together and count them as one dive. The 10 minute rule predates any dive computer.

why exactly?

A couple of reasons. Students need practice setting up and breaking down tanks. They were shorted essential practice. Also, they made two short dives instead of two longer dives. Longer dives not only give more time to enjoy the dive, they also give more experience diving. Now, there are times, a shorter dive is appropriate - low on air, approaching the NDL or cold divers. In all of those situations, you need to get out of the water, either for warmth, to switch tanks or to wait out a longer surface interval.

I've never heard of a 1 hour minimum surface interval for nitrox dives. One of the advantages of diving nitrox is you can have shorter surface intervals (but still not less than 10 minutes)>

 

[H2Andy]

It's based on dive tables. If you have a surface interval of less than 10 minutes, you add the bottom times together and count them as one dive. The 10 minute rule predates any dive computer.

wow... so why provide with the possibility of a 6 or 8 minute surface interval?

could you point me to where the rule is written? i am amazed i was never taught this.

I've never heard of a 1 hour minimum surface interval for nitrox dives. One of the advantages of diving nitrox is you can have shorter surface intervals (but still not less than 10 minutes)>

as i said, it's a recommend practice. it's in my PADI Nitrox textbook, and
i believe they took it from the Berkley Diving Safety Manual, section 7.2.2.5.4; i
think they got it from the LA County program.

http://72.14.203.104/search?q=cache...ded+surface+interval&hl=en&gl=us&ct=clnk&cd=5

 

[Scuba_Steve]

Nope we got out twice and doffed and doned ate lunch during one break the other dives we just floated and doffed and doned gear on the surface. Except for the navigation we had to snorkle a corse on top head down and then run the same one at 15 ft. I was off by only a few degrees underwater.

OK that's better. your first post looked like you just stayed on the surface wthout the in-between stuff. I guess others thought the same thing No problem.

Andy:

Chill out dude, I said "you two" instead of the first poster, and yes he did say that.

The rest is spot on, Dude.

 

[H2Andy]

Andy:

Chill out dude, I said "you two" instead of the first poster, and yes he did say that.

lol... ok... i guess he must have changed his post later

 

[Scuba_Steve]

I can vouch for the "recommended SI of 1 hr" for the Padi Nitrox (EAD) course. It's in there.

The 10min thing I've never heard of in the Padi (or any other) system, but for training dives we require the gear break-down and re-assembly for every dive.

Regards

 

[cummings66]

I'll third the Nitrox book suggesting a 1 hour si, it's most definitely in there and is in my padi ow book as well. I think they like 1 hour si's.

 

[Walter]

wow... so why provide with the possibility of a 6 or 8 minute surface interval?

No such possibility exists in any tables I would trust.

could you point me to where the rule is written? i am amazed i was never taught this.

You can look here:
SCUBA Diving third edition by Dennis Graver Chapter 6 Dive Planning, page 146

Dive Table Terms

surface interval time (SIT) -- The elapsed time (rounded up to the next whole minute) from when the diver surfaces following a dive to the time the diver begins the descent of a repititive dive. The minimum SIT is 10 minutes.

You can also look here:
NOAA Diving Manual Fourth Edition

15.6.4 Repetitive Dives

NOAA defines a repetitive dive as one that begins wthin 12 hours of a previous dive........ If the second dive starts less than 10 minutes after the first dive, it is considered an extension of the previous dive. NOAA nitrox decompression tables utilize the same rules and proceedures on repetitive dives.

I suspect PADI abandoned the 10 minute minimum SIT when they started using the RDP around 1988 or so. Scary!

I may have found where they got the idea for a 1 hour SIT for nitrox. In the NOAA manual, there are examples (15-4) comparing dive profiles with EAN 36 and air. In the examples, a 1 hour surface interval is used.

 

[H2Andy]

wow, interesting

thank you...

PADI certainly got away from that... i am pretty sure we never covered
anything like the 10-minute interval in my OW class