Quick RDP table question :)

Hi there, just doing my homework from dive 5, and I was wondering if anyone can confirm my answer to a question. I'd normally wait for my tutor to point me right, but I'm doing the test tonight, and if this is wrong then I need straightening out.

Q: What is the minimum surface interval required between a dive to 20 metres/70 feet for 29 minutes followed by a dive to 14 metres/50 feet for 39 minutes.

A: zero minutes. (I hope)

edit: ok, a bit of working out:
1/ first dive puts you in pressure group M.
2/ 2nd dive has 59 minutes of residual nitrogen available at 14 metres. (to make a total of 98 mins, NDL@14 meters)
3/ to add 57 mins of residual at 14 meters, I'd need to be in PG:P
4/ Since a SI is never going to take me from PG:M to PG:P, the SI _required_ is 0 minutes.

Many thanks for your thoughts I have a dunce's hat on standby.

Ah well, too late now.

I was right no SI is needed with those two dives.

Just done the paper test, and got 98%. The question I got wrong I think is a little subjective and dependant of a bunch of variables. I said I'd have my buddy's alternate air before I did a cesa. PADI say no.. I think in real life it'd depend on all sorts of stuff, not the least of which would be panic. Depth, proximity to buddy, visibility..

Anyway, I was wrong. Hey ho.

Ahhh the infamous question 35 if I'm not mistaken.

Try and think of the question as 'Starting with a normal ascent, if the previous option wasn't available, what would you do?'

Well done for passing, sorry I didn't get your PM earlier, but I've been out drowning students and catching crabs*




* I hasten to add, not from the students

*shudder* buy a computer! *shudder*

Ooopsie - Role Model behaviour - well done chap

Originally Posted by Silly Car

Ahhh the infamous question 35 if I'm not mistaken.

Yep

Originally Posted by Silly Car

Try and think of the question as 'Starting with a normal ascent, if the previous option wasn't available, what would you do?'

Well ok.. but I'm still not convinced. If I can see air three feet away on my buddy, and air 18 meters away straight up, I'm pretty sure I know which one I'll go for. (obviously I've not been there or done that, so I'm ok with being wrong on this one.)

Originally Posted by Silly Car

Well done for passing, sorry I didn't get your PM earlier, but I've been out drowning students and catching crabs*

No worries.. I'd gone over it a few times and was getting pretty convinced I was right by the time I went to school But thanks for your reply.

So it's just four dives at Stoney cove this weekend and we're all qualified. I'm going to wear a lot more under the drysuit at the cove though. The familiarisation in the pool has left me aching with bruises all over me. And plucked a fair amount of body hair off me

Originally Posted by Kebab The Cat

So it's just four dives at Stoney cove this weekend and we're all qualified. I'm going to wear a lot more under the drysuit at the cove though. The familiarisation in the pool has left me aching with bruises all over me. And plucked a fair amount of body hair off me

Be a man. Wear a wetsuit you girly wuss. that's what I'm gonna do on Sunday, not being drysuit qualified

Oh, and congratulations my darling, you rock!

Drysuit, yah soft southern shite, get in the water with a semidry on at most, my training sites are currently 17°C

For the avoidance of doubt the correct order for ascents is:

1. Normal Ascent
2. Alternative Air Source Ascent
3. Controlled Emergency Bouyant Ascent
4. Buddy Breathing (you and your buddy are using one air source remember)
5. Bouyant Emergency ascent (that could see you in the pot or worse)
6. Check your FUCKING gauges*

* I get really pissed with any diver on my boat charters who fail to monitor their gauges. Thankfully none of them rely on pony cylinders (see here for my view on them) /breathe

Originally Posted by Silly Car

For the avoidance of doubt the correct order for ascents is:

1. Normal Ascent
2. Alternative Air Source Ascent
3. Controlled Emergency Bouyant Ascent
4. Buddy Breathing (you and your buddy are using one air source remember)
5. Bouyant Emergency ascent (that could see you in the pot or worse)
6. Check your FUCKING gauges*

See I think that's the order I put them in. The 'correct' answer had 2&3 the other way round.

I think. Ummm.

And another thing.. they're telling me I'm in a drysuit. I didn't pick it. I don't really care one way or the other, but I'm damn sure I'm wearing something under the drysuit this time, if only to save the bruises and the hair pulling.

I'm the student here, I'm just doing what I'm told

Originally Posted by Silly Car

Drysuit, yah soft southern shite, get in the water with a semidry on at most, my training sites are currently 17°C

I've come to the conclusion that it's never warm enough for a wetsuit/semi in the UK. Miny you, I'm a wimp and wore a drysuit in the Red Sea last winter, 21-22C

Originally Posted by Silly Car

For the avoidance of doubt the correct order for ascents is:

1. Normal Ascent
2. Alternative Air Source Ascent
3. Controlled Emergency Bouyant Ascent
4. Buddy Breathing (you and your buddy are using one air source remember)
5. Bouyant Emergency ascent (that could see you in the pot or worse)
6. Check your FUCKING gauges*

* I get really pissed with any diver on my boat charters who fail to monitor their gauges. Thankfully none of them rely on pony cylinders (see here for my view on them) /breathe

I would put no.6 first, then there's no need for the others.

And I'm not getting into another pony argument

If you are going in the open water with a drysuit you WILL need something under it, depending on what type of suit will determine what you should be wearing:

Trilaminate - ideally a base layer to wick away sweat (I have been known to use my bike EDZ set) and a thermal layer something fleecy top and bottom
Neoprene - base layer as above and an additional thin thermal layer
Crushed Neoprene - as Trilaminate

In the winter, I have to carry around 6 kilos of extra lead to combat additional bouyancy from the thermals which are as follows:

EDZ Base layer
M&S Merino Wool thermals
Fourth Element Xerotherm Arctics (mutts nuts)
UGGI two piece or Weezle extreme

I am contemplating a heated kidney belt for this winter

Last night it was just the Xerotherms and I could have done an hour or more. A very cool* Trilaminate suit by the way



* As attested to by the sprogs at Browns Bay when diving with Tazzie



EDIT - Druid, I agree completely with your point about checking gauges

The school suits are trilaminate. I'll have to dig out some trcksuit bottoms and long sleeve Tshirts... that's about as close as I can get to what you describe. :-/

Wearing it with just swim shorts was really quite unpleasant.

Originally Posted by Kebab The Cat

The school suits are trilaminate. I'll have to dig out some trcksuit bottoms and long sleeve Tshirts... that's about as close as I can get to what you describe. :-/

Wearing it with just swim shorts was really quite unpleasant.

You'll need more than that, membrane suits have absolutely no insulating properties. At the very least wear a fleece or a sweatshirt as well as the t-shirt, or you'll be cold as well as uncomfortable. Your instructor must be an evil bastard, letting you wear just swim shorts under a drysuit. We used to tell students to wear at least tracksuit bottoms and a long sleeved top, not for the warmth, but for comfort.

Edit: just read throught the previous posts, this will be too late for you today

Well the weekend is over and I'm all qualified to paddle around in the shallows now
The school did in fact have full fleecy undersuits for us to wear under the drysuits, so it was all pretty comfortable and toasty.

One girl in our little group of four OW students was pretty hopeless.. she just could not conceptually grasp that she needed to add air as she went down and let it out as she came up.. so her bouyancy was obviously all over the place. Couple that confusion with her regularly mixing up the buttons on her bcd inflator hose meant that she was a bit of a 'mare generally. Obviously I was buddied up with her for the weekend..

<------------That's me watching her as she went uncontrolled ascent again.. and again... and again. In the end I got pretty good at grabbing a fin and dumping all my air..

Anyway, thanks for all your comments folks, we're off on holiday in a couple of weeks, and after that maybe we'll see you for a dive sometime

Originally Posted by Kebab The Cat

Well the weekend is over and I'm all qualified to paddle around in the shallows now

*proud*

xxx