Sentinel Frame

On the second day of my crossover course I discovered the worse feature of the Sentinel. I sat of a low wall to finish kitting up and I couldn't get up. The wretched thing is too short in the body AND it slopes so once it rolls you backwards you're stuck.

Now after the Inspiration with its no nonsense sit down, pull the straps round you then stand up and go diving attitude this was not a happy moment. It's taken me a year to fix it but here it is: The Kent Tooling stand.

Now John at Kent Tooling understands divers and when I phoned to see if he was interested in quoting me for a bit of one-off metalwork he knew that I wouldn't be the only person with the problem. However I was the volunteer. He listened to my plan, factored it through his available parts, toned down the more wild ideas and made me a stand to solve the problems.

He made an in-house test version and I drove over and we bolted things together and measured things as engineers will. He wouldn't let me take that one home as he wanted to test something more realistic.

This is what I got as the Mark 1 - test prototype:

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Basically it is a new 'foot' with his usual frame construction to go on the bottom. Let's run through a quick install...

These are before shots of the Sentinel trying to stand up.

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My Sentinel is already not standard as it has both the extended backplate that John made for me (so the plate locates on the big bones of your pelvis and not the small of your back so the thing doesn't wobble about so much) plus the much softer webbing in yellow. The plate comes off, the wing comes off, the plastic foot comes off, the new stainless foot goes on and reassemble.

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Stand it up on the frame

P1140477.JPG What you can't see from this is that if I now sit in front of it the unit is positioned just where it should be. It is upright and the straps come over my shoulders as I'm kitting up just as they will in the water. In a few kilos of stainless the whole thing is transformed.

That made the rest of the set-up so much easier. I just sat in front of it and put my hands back. Could I reach it? Did it work? Tested.

Right: fit the suit inflate bottle:
Just don't talk about the angst of working stainless at home, 11 miles from real tools on a Sunday.

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That seems OK but putting it on the nice Metalsub bracket rather took away some of the space I wanted for the FaMi can-lamp battery.
However there is a lovely, obvious space... Just no lovely, obvious way to attach it there yet. A quick botch with Velcro tape will do for now.

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Right. Time to get it in the water. Tuesday night is club pool night.
I tried to find a photographer but we're up to our ears in trainees so it didn't happen. Pictures next time maybe.

I took 4kgm off my belt which slightly surprised me as it only weighed 3.5kgm but I suspect that I'm not really going to sense half a kilo either way. Also there was no fore-to-aft trim change which is a good thing because I've already filled the 'ear' bags on the Sentinel. My 'heels just above my head when relaxed' trim is still there. All the new weight pretty much centres on your belt so that's the reason for that. Kitting up was just so much easier, you just sit in front of it and do things up, while in the water nothing noticeable had changed. I think I'll put an extra kilo on in real water as it was a trifle edgy at times although I might just try and move some of the lead into the frame.

Nothing changed? No, that's not really true. I used to belt hang the suit inflate and the can lamp battery and that truly sucked. That problem is now utterly gone.



Real diving... Well Vobster Quay as this is January and the club isn't doing much as, with the storms of the last few weeks, the sea off Sussex is like Yoghurt.
Diving with Janos on another rebreather, the JJ. It was 4°C with teeth however we drove there and Janos had sensibly booked us a parking space. We kitted up and dived.

Frankly there isn't much more to say than that. I had ordinary dive problems, my old mask leaked plus I got cold and when I dekitted I found I had a wrist seal on its way out and I was all wet. Diving I bumped through things and under things and the case hit stuff but I was never aware of the stand touching anything. The suit inflate hose could do with being an inch or so longer as it is going tight when I stand up and the weight comes on but that might be just how I dress the first stage. I deliberately dived 2kgm overweight after the pool dive expecting a bit more suit inflate would be needed so I was initially disappointed to be cold but on discovering I was all wet I forgave things.

I was more interested in playing 'wearing my mask under my hood' (it works) and the happy discovery that the best way to clear a gurgully loop is a nice slow 360° roll (think about it).

Frankly it was very boring and as a result I was very pleased.
I'll take it to sea based on that.
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P1240495.JPG Good points:
Kitting up. If you've put on a Sentinel and had it roll you on your back, or try too, you'll know what I mean. I took it to Scapa last year and always found a problem going from it sitting on the bench with me getting into the harness in front of it to me sitting on the bench. I'll just have to try it on a RIB.

Somewhere to put things. As I've said belt hanging the suit tank and the lamp battery sucked. If I can move out the extra lead and dispense with the belt I'll feel that is an added bonus. If you don't have a huge fluffy undersuit like mine you might dispense with most of your lead and have the weight working for you instead.

John puts loops for clipping stages on. Now I confess they will need bigger clips than my stages have but I'm going to try them. I might not end up using them but it's nice to have the choice.

Bad points:
It makes the already heavy Sentinel heavier. With stand, trim weights, suit inflate and can lamp I've got 52kgm to wrestle about. OK, before the advent of the stand a lot of these were separates so that's not a fair number but when you can just leave things installed you will. Conversely I can put my arms into the harness on the ground and get up with all this clutter and I'm a 5ft9 12stone grandfather.

It is very tall. The Sentinel is a bulky piece of kit at the best of times and standing next to Janos's JJ it seemed a lot bigger. To the top of the hoses is now 82cm tall , just over 32inches, now. This might be a problem to people who want to transport it upright in a saloon car. It fitted in my Rangie OK and I just seat belted it for stability.

If something gets under that stand and I sit it down on it it's going to die. My current worry is the torch cable but stage hose or just a simple mask thrown behind you as you sit down could be very vulnerable.


Next stop is to sort out a proper battery mount and put it in wild water.
Oh and get some real pictures.


The pictures can be accessed by clicking the thumbnail but they can to be up to 2.5M files
Pictures by Nigel Hewitt
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