Just can't reach Isolator

[wannadivenotwork]

Well, 4th dive now in an attempt to do shutdowns, and although some excellent advise from buddy on tightening up harness and turning isolator towards head, I really don't think I can lay my life on the line and say I can shutdown when it really matters. I ust don't have the movement in my arms.

I would prefer not to invert - personal choice rather than anything DIR related, which leaves the use of Slob Knob. Don't want to use this either really - hence all the shutdown practice, but I really don;t see an option.

I have read nearly every post and article on t'internet rearding trying to do shutdowns, and debates on inverted etc, and think the Slob knob is the best work around.

Where can I get one of these things, and how much to they cost and can I fit one?

[Fiona]

OMS £85 - Divelife

I know Custom divers do one as well.

[wilbo]

so you've adjusted your harness - thats the first step.

Are the cylinders the correct height within the bands? The top edge of the top band should sit at the point where the cylinder starts to curve..

Is your undersuit too tight? or is some of the fabric trapped low down when you do up your harness? sometimes this will restrict.

Is your drysuit correctly sized? Get into all of your kit - as you would if you were diving and sit down in a chair. Can you reach back and isolate? Are there ay parts of your suit that is stretched too much? Again - are there any folds of suit trapped? While in the water loosen the harness around the waist and do a 'superman' stretch - to pull all material to where it should be - then do up harness.

Does your drysuit have a rear entry zip? Rear entry suits restrict reach. I know this - I have a new othree RI2/100 which has been properly sized for me. fits great and is a joy to dive. Isolate? forget it. When doing shutdowns I 'plow' the bottom of the seabed/quarry. had the suit altered to just more reach. still very little joy..

In the end I changed to a front entry protec. shutdowns are now easy peasy.. sorry - this might not be the thing you want to hear - but thats what it took for me
also make sure that you are not head up/feet down when you are doing them. the cylinders will slide down your back. get your feet and arse up and head down. the cylinders will slide forward.

Edit: another good way of reaching the isolator is to place the back of your hand onto the back of your head and use your head to push your hand backwards onto the isolator..

So it looks like I will have a brand new (15 dives) Othree RI2/100 for sale soon..

[Mark Chase]

Fitting is easy but what manifold do you have?

Hopefully MDE which is by far the most slob knob friendly one there is. Purely because the isolator is easy to turn regardless of gas pressure.

If you haven't got a MDE I would make sure part of fitting includes a good strip and lube of the isolator. Its easy to do and requires nothing much more than 02 grease.

I would suggest you consider mounting it like this:



So you can still reach the valve manually in the unlikely event of a total failure of the slob knob. I route the slob knob under my arm following the route of the long OMS or custom divers type wing inflater and i bungeed it to the wing inflater so you always know where it is.



Over the shoulder on an over the shoulder inflater hose is just as good if not better.

Take it apart and grease it with silicone grease before assembling it and repeat about twice a year. Keep the isolator valve moving freely so as not to stress the slob knob.

Never crack open the valve with the slob knob always use your hand on the valve. Have the valve two turns open and never force it shut with the slob knob. Shut it sure but never force it shut unless its an emergency.

Following these basic rules i had a grand total of zero slob knob failures during my time using one.

Good luck

ATB

Mark Chase

[Scuby]

Are you a long way from being able to reach the valves? The only reason I ask is a friend from my old club managed to go through 3 or 4 slob knobs in just over a year - they just rusted up and were forming a growing pile in the corner of his garage.

Edit: although if you look after them like Mark then you might not have that problem

Also I assume you can reach the pillar valves and its just the isolator you have a problem with? I know a few people who can't reach any of them, but remember the isolator only protects half the gas - you need the other two valves to be able to access the "broken" side if something breaks.

David

[Mark Chase]

Originally Posted by wilbo

so you've adjusted your harness - thats the first step.

Are the cylinders the correct height within the bands? The top edge of the top band should sit at the point where the cylinder starts to curve..

Is your undersuit too tight? or is some of the fabric trapped low down when you do up your harness? sometimes this will restrict.

Is your drysuit correctly sized? Get into all of your kit - as you would if you were diving and sit down in a chair. Can you reach back and isolate? Are there ay parts of your suit that is stretched too much? Again - are there any folds of suit trapped? While in the water loosen the harness around the waist and do a 'superman' stretch - to pull all material to where it should be - then do up harness.

Does your drysuit have a rear entry zip? Rear entry suits restrict reach. I know this - I have a new othree RI2/100 which has been properly sized for me. fits great and is a joy to dive. Isolate? forget it. When doing shutdowns I 'plow' the bottom of the seabed/quarry. had the suit altered to just more reach. still very little joy..

In the end I changed to a front entry protec. shutdowns are now easy peasy.. sorry - this might not be the thing you want to hear - but thats what it took for me
also make sure that you are not head up/feet down when you are doing them. the cylinders will slide down your back. get your feet and arse up and head down. the cylinders will slide forward.

So it looks like I will have a brand new (15 dives) Othree RI2/100 for sale soon..

A front entry dry suit is the only thing i havent tried to make shutdowns workable. I have tried everything else including all sorst of undersuit and no under suit at all (just a base layor).

I still find shutting down the isolator incredably slow and hard. 20-30 (totaly unacceptable) seconds with manual isolation and about 3 seconds with a slob knob



ATB

Mark Chase

[Mark Chase]

Originally Posted by Scuby

Are you a long way from being able to reach the valves? The only reason I ask is a friend from my old club managed to go through 3 or 4 slob knobs in just over a year - they just rusted up and were forming a growing pile in the corner of his garage.

Edit: although if you look after them like Mark then you might not have that problem

Also I assume you can reach the pillar valves and its just the isolator you have a problem with? I know a few people who can't reach any of them, but remember the isolator only protects half the gas - you need the other two valves to be able to access the "broken" side if something breaks.

David

The spring in the Custom divers one is stainles steel so it shouldent rust at all. When i sold my one it was still rust free except for the light rust you can see on the outer casing which came from the grub screws and could be wiped off.

I broke a slob knob by droping a twin set but apart from that my one (which i baught second hand) was still fine after 5 years of diving it.

Gas planning should allow ascent on remaining gas in an isolated twin set which assums your totaly incapable of reaching the outer valves and will loose all gas from one tank.

Thats why I was often seen taking a pony with me on the second dive of the day dispite having a twin set and not needing deco gas.

ATB

Mark Chase

[wannadivenotwork]

Mark, looks like the answer.

After my dive today, I also need to re-route the CD inflator under my arm, so it would be nice and easy (and obvious) to route the slob knob with it.

In regards to the manifold, I just bought the 12Ltr Twinset from Kent Diving, and although I have looked at it, i can't tell (short of calling kent diving) what make it is. So, will a standard CD or OMS slob knob fit?

[Mark Chase]

Originally Posted by wannadivenotwork

Mark, looks like the answer.

After my dive today, I also need to re-route the CD inflater under my arm, so it would be nice and easy (and obvious) to route the slob knob with it.

In regards to the manifold, I just bought the 12Ltr Twinset from Kent Diving, and although I have looked at it, i can't tell (short of calling kent diving) what make it is. So, will a standard CD or OMS slob knob fit?

Kent diving usually use Beaver manifolds as standard or MDE as an option.

The manifold in my pic is an MDE and they are stamped up as MDE. If not then phone Kent Diving and ask but its probably a Beaver.

Kent diving sell slob knobs as well so ask for one with the correct fitting.

ATB

Mark Chase

[wilbo]

Originally Posted by Mark Chase

A front entry dry suit is the only thing i havent tried to make shutdowns workable. I have tried everything else including all sorst of undersuit and no under suit at all (just a base layor).

I still find shutting down the isolator incredably slow and hard. 20-30 (totaly unacceptable) seconds with manual isolation and about 3 seconds with a slob knob



ATB

Mark Chase

Mark - not sure if you remember the DIR day at Vobster earlier in the year - you brought the video camera.. I had the same problems - ploughing the side of the quarry - simply because I couldn't reach the valves properly - then of course the old lactic acid creeps in and makes shutting them down harder..

I would say try a front entry - we are similar sizes - so feel free to try my protec and I recon you will see a difference.

edit: plus looking at you photo - your feet are a little down..