Diving Twins ....

[ross the diver]

Originally Posted by Freeflow

Some organisations [TDI and PSAI for example] do a 'twinsets fundamental' course. I experimented in nice shallow water until I was comfortable and got on with it. I don't have a drysuit qualification either , so should I only dive in a semi?

It looks a bit OTT to insist on this, but then one PADI school has a DSMB speciality! Strange that I distinctly recall seeing that you had to teach any skills appropriate to the local environment in the manual when I used to teach.

When teaching Open Water I would dive on a single cylinder, advanced was always on twins, mainly because I could easily do the three dives per day and still have over 50 bar left.

On the subject of the PADI Tec courses, I don't rate them very highly, but that's another can of worms for another day...

the idear of having a speciality in twin sets is grate it will stop a 12l clyinder droping out from the home made webbing or s/s bands that have not been done up falling through the bottom of my boat, any one who dives on a twin and has not got a clue of how it works and it fits together should not be diving on them ( but thats my view :-) )
I teach the DSAt (padi) tec course and apart from the dir courses it is the only course out there that will take a diver through from never had used a twin to diving on twins 2 stages at 50m and and doing deco.. i see people trained for 50m having only dived 4 or 5 dives at a depth of 30m, then beeing given a ticket to say they can use 100% to 60m some thing wrong there an as a skipper its me that has to do the paperwork when things go wrong!!

please walk before you run people!!!!!!!!

[dublinbay]

Originally Posted by Lazlo

YMMV - Had to look that one up! Could be true.

It is unreasonable to expect a student to bail me out. I talk only of a hypothetical catastrophic OOG failure. Like you, if needed I would CESA my way out. In real life (not the internet) I would have already ended the dive once my air started getting low, then had a stern word with myself about the amount of air I'd decided to go in with.

Leaving students on their own should never happen, short of a totally unreasonable and unforseeable set of cirumstances occurring.

Just to clear that up

Why would you have a stern word with yourself? Would you dive with 120bar in your tank? Would you let a student in the water with 120 bar ?
How much is a fill?

[TerryH]

Originally Posted by Lazlo

When I teach Open Water, I use the same sort of equipment that the students use.

Seems sensible to me, putting myself in a student's shoes it would seem odd that the instructor needed all this scary extra equipment, when I have to do without.

Role model behaviour and all that...

Absolutely.

It's extremley unhelpful to have kit that differs from your students.

Student on strapped single with A clamp and usually hose routings.
Instructor on Bolted twins with Din and hoses split between two.
Even maybe long-hose/ necklaced.

New student doesnt quite remember how to kit up, looks over at Instructor
and sees what!!!!!!!!!!!!!!

Next imagine in water an instructor going over drills.
Better be a three then, because he will be unable to demonstate
effectively as his kit is different.

Bottom line is that basic courses = basic kit with Instructor the same.

Secondry level courses where you are going over 18/20m, of course, now
is the time to think redundancy.

TerryH

[Lazlo]

Originally Posted by dublinbay

Why would you have a stern word with yourself? Would you dive with 120bar in your tank? Would you let a student in the water with 120 bar ?
How much is a fill?

I use a 10L tank and the students have full 12L tanks. Occasionally I have used 1 fill to 2 of theirs. There is a possibility that I could run out before them - but not if I keep on top of things.

[bob wippin]

Originally Posted by ross the diver

the idear of having a speciality in twin sets is grate it will stop a 12l clyinder droping out from the home made webbing or s/s bands that have not been done up falling through the bottom of my boat, any one who dives on a twin and has not got a clue of how it works and it fits together should not be diving on them ( but thats my view :-) )
I teach the DSAt (padi) tec course and apart from the dir courses it is the only course out there that will take a diver through from never had used a twin to diving on twins 2 stages at 50m and and doing deco..

This isn't strictly true in my experience. I was taught TDI, I don't believe they have a specific course for twins. Having seen other people being taught TDI Deco aswell, you get some people turn up who have been diving twins for years and other really experienced divers who never really needed twins before so turn up never having used them.

The instructors have always given them enough of a talk through about twins for them to not need to do a specific course in it. It's all built into the course, under the equipment requirements section, there are loads of drills on shut downs, trim and deco bottle positioning anyway. I think it is bang out of line to make people do a twinset course when you can be told what you need to know in 10 minutes (I know this to be true, as I have been there, what I wasn't told only took a few seconds to work out)

I think the only place for a twinset course is for recreational divers who need the air, but are not looking at getting the twins purely for redundancy to move into deeper diving. Besides apart from getting used to them underwater, which comes with practice, the only thing a recreational diver needs to know about a twinset is how to open the manifold, then leave it open and use it as a big single. Shutdowns etc is really in my opinon moving into tec diving, from recreational depths you will always have a third of your air, so it is no problem coming up from 30m anyway even with a freeflow. If you can't do up the bands without doing a course then I think you have to question can you get on a dive boat without doing a boat diver speciality course.

i see people trained for 50m having only dived 4 or 5 dives at a depth of 30m, then beeing given a ticket to say they can use 100% to 60m some thing wrong there an as a skipper its me that has to do the paperwork when things go wrong!!

please walk before you run people!!!!!!!!

I was in the same boat when I did my deco course. Don't really see your problem here. I think you are right to question this if they are only taken down to 30m or so in training, when the course will qualify them to go a lot deeper, they clearly shouldn't pass the course. Besides, the DSAT tec courses won't allow you to even undertake the course with this level of qualification will they? I thought they made you do several hundred dives at several depths, including dives past 30m before doing there tec courses.

[Freeflow]

Originally Posted by bob wippin

I was in the same boat when I did my deco course. Don't really see your problem here. I think you are right to question this if they are only taken down to 30m or so in training, when the course will qualify them to go a lot deeper, they clearly shouldn't pass the course. Besides, the DSAT tec courses won't allow you to even undertake the course with this level of qualification will they? I thought they made you do several hundred dives at several depths, including dives past 30m before doing there tec courses.

The big problem is the number of people [and if I have heard "Nitrox lets me go deeper, yes?" a hundred times] who look at experienced divers and want to be like them without doing the time. Me, I'm cautious to the point of cowardace and although I have had my normoxic trimix ticket [max 60m] for nearly 2 years I don't see the need for full trimix for another year or two. It was 500+ dives before I started on the serious tech stuff [I'm not counting PADI nitrox].

The old pilot's adage that you start out with a full bag of luck and an empty bag of experience, and the trick is to fill the bag of experience before you empty the bag of luck requires a slight ammendment when it comes to advanced diving-the bag of luck compresses the deeper you go so there is less luck in it.

Finally, when you know all there is about diving, stop diving as you are a danger to yourself and others.

Rant over, normal service resumes...

[e-aquanauts]

[limeyx]

Originally Posted by TerryH

Absolutely.

It's extremley unhelpful to have kit that differs from your students.
TerryH

I wore a backplate and wing in my open water class -- does that mean my instructor should have worn them also ?

[up 4 it]

The nearest thing in BSAC to a twins course is the Extended Range Diving Course ERD, which covers the correct use and configuration of twins, shutdown drills, and stage cylinders.

A very good course for anyone diving with twins.

Steve

[Mal Bridgeman]

Originally Posted by TerryH

Absolutely.

It's extremley unhelpful to have kit that differs from your students.

Student on strapped single with A clamp and usually hose routings.
Instructor on Bolted twins with Din and hoses split between two.
Even maybe long-hose/ necklaced.

New student doesnt quite remember how to kit up, looks over at Instructor
and sees what!!!!!!!!!!!!!!

Next imagine in water an instructor going over drills.
Better be a three then, because he will be unable to demonstate
effectively as his kit is different.

Bottom line is that basic courses = basic kit with Instructor the same.

Secondry level courses where you are going over 18/20m, of course, now
is the time to think redundancy.

TerryH

Terry

Philosophically I approach the Open Water Qualification differently to you.

I do not demonstrate skills to students in Open Water....that's what the confined water training is for, AFAIAC. They don't go into Open Water till they can perform the skills based on visual prompts from me.

When Students are kitting up, I am on hand and talking to them spotting any stress or problem situations and resolving and relaxing the students as much as possible. I explain my kit is different and why.

I have no intention of changing your opinion and you won't change mine but I did want to explain my approach.

Rgrds
Mal