feedback on Sentinel

aqua orca · 17th July 2008, 18:27

hello,
I appreciate any feedback on your experiences with the Sentinel. comments on mechanical quality, ease of use, robustness, breathing resistance in currents,
thank you in advance
aqua orca

ch3micaldud3 · 17th July 2008, 20:15

Hi there,

Check out the different posts on the Sentinel... That should give you already a pretty good idea about this very beautiful rebreather...

As I'm awaiting my course and arrival of my very own Sentinel in September, I'll be reading every post about it

Keep those experiences & pictures coming ...

Marvintpa · 18th July 2008, 13:26

Good luck with your request.
For some reason I don't understand, the amount of information and talk about the Sentinel has been surprisingly small - I think there was more talk about it before it was launched.

There are a few threads on Rebreather World, but not much.

I haven't had mine in current yet so can't comment on that, but overall breathing resistance is very goood. Build quality and ease of use are good. The canister is a little different for packing and inserting, but not bad. The quality of the machining is excellent, and the electronics are some of the best available.

depth · 18th July 2008, 14:31

Hi

I do not dive the sentinel myself, but I have seen it up close and I think it has some very nice features. However, from my point of view I think the design has two major drawbacks:

1. The rebreather is huge! It sticks to far out from the back.
2. Your exhale gas goes directly in to the scrubber, so if you use the sofnolime option, the absorbent will be soaked if you get water in the loop through the mouthpiece.

Can anyone shoot a picture at the sentinel besides another Rebreather like the meg? A top down picture will show the size difference....

Just my opinion, hope you can use it...

/Christian

**nigelh** · 18th July 2008, 15:01

Quote: (Originally Posted by Marvintpa)

For some reason I don't understand, the amount of information and talk about the Sentinel has been surprisingly small - I think there was more talk about it before it was launched.

Because lots of us are idly reading the manual waiting for ours to come due.

I'm October.

By about January we should be driving the rest of you mad swapping detail stories and fixes.

Mixaddict · 19th July 2008, 04:20

Quote: (Originally Posted by depth)

2. Your exhale gas goes directly in to the scrubber, so if you use the sofnolime option, the absorbent will be soaked if you get water in the loop through the mouthpiece.
/Christian

As a diver and instructor on the Sentinel, I can tell you that water ingress into the scrubber does not seem to be any more of a concern than on OTS counter lungs. The way the unit is designed, it is very simple to flush water through the system. Additionally, the insulation of the canister is some of the best on the market, which keeps the heat at a substantial level. I believe this contributes to the evaporation of water in the scrubber more quickly than a lot of units.

During our initial training, one of the students while doing drills, accidentally left his dsv open with the loop out of his mouth at about 20 meters. It floated above his head for 10 or 15 seconds. We were all very anxious after the dive to inspect his scrubber and see how much water was in the bottom on it. To our surprise, there was almost none. A combination of forcing water down through the scrubber and out the OPV in the bottom of the scrubber as well as the heat of the scrubber completely removed the water. It was actually quite amazing.

I like the unit a lot. The electronics are top notch. I really don't notice the size of the unit at all, especially in the water. I love the uncluttered chest area. It trims out almost perfectly for me right out of the box. The build quality is wonderful. The service from Delta P has been great. The breathing hoses are VERY long, but when you feel how easy the WOB is, you can put up with long hoses! The BOV is very good. The forced pre-dive checks may seem draconian to some, but I can already tell you from personal experience, that they absolutely force you to pay attention! Part of the thickness of the unit is because of the way the insulating space is around the canister. It is obviously by design, and it simply works. Good canister duration. Good WOB. Good durability. Good performance What else could you ask for? I know, I know, half the size, half the weight and half the price! Of course, with that, you would get half the performance! With many of the same performance features and some improvements from the Oroborous, it really is a VERY nice unit. Try it, you'll like it!

Regards,
Randy

Peter M · 20th July 2008, 18:54

I've just returned from a weekend of diving on mine, it was a mixed weekend with currents "like being in a washing machine". I had the only Sentinel on the boat and when it sat along side inspirations, twin sets, and singles it didnt seem any "deeper" than anything else and i had six inspo divers looking at it very closely.
Dealing with the currents we encounterd didnt pose any more problems than any of the other divers. As for the long hoses i like the as i feel i have more freedom to move my head, just mark them when you get them comfortable.
This is my first rebreather and after the initial hicups which Delta P dealt with very quickly it has been really great, I have made a few mods like a longer wing inflation hose and caps to hold the first stages.
Electronics wise i am gradually getting used to them being able to use a vr3 is a great help.
I can also say that the scrubber doesnt get all that wet as i also left my loop OPEN above my head for approx 10 secs in training and the sorb was basically dry.

depth · 20th July 2008, 19:41

Quote: (Originally Posted by Mixaddict)

The way the unit is designed, it is very simple to flush water through the system. Additionally, the insulation of the canister is some of the best on the market, which keeps the heat at a substantial level. I believe this contributes to the evaporation of water in the scrubber more quickly than a lot of units.

Hi Randy

The above mentioned sounds plausible but imagine diving at 100m and the shit hits the fan, you lose your dsv and enough water enters the loop to almost completely soak the scrubber. You relocate the dsv and go back on the loop and realizes the unit is flooded causing increased WOB so you decide to dump the water through the OPV. You are now on the loop on a rebreather with a scrubber that might/might not function. If the scrubber is not working you can only hope you have time to realize an incoming CO2 hit and go OC. Just a thought....

But does anyone know if they have tested for scenarios like this? As I remember, the sentinel is rated for 100m, but have they ever done a flood/recovery test at 100m with the unit? I hope they have since they chose this design... If they did, and the tests went well, I would have no problems in diving this unit, except from the size maybe.

Hope I am not too much off topic

Christian

Amphibiman · 23rd July 2008, 22:07

[quote=depth;198924]

Hi Randy

The above mentioned sounds plausible but imagine diving at 100m and the shit hits the fan, you lose your dsv and enough water enters the loop to almost completely soak the scrubber. You relocate the dsv and go back on the loop and realizes the unit is flooded causing increased WOB so you decide to dump the water through the OPV. You are now on the loop on a rebreather with a scrubber that might/might not function. If the scrubber is not working you can only hope you have time to realize an incoming CO2 hit and go OC. Just a thought....

Hi Christian,

I was the student Randy was mentioning. This is my first rebreather that has a BOV. So while performing skills I was going back and forth opening and closing the mouth piece and thought it was closed when I ditched the loop. Anyway, what Randy was trying to say is that a whole-lotta water entered the loop and went straight through the scrubber. If I remember correctly we did an additional 60 minutes after the event and during break-down it was appearent that whatever water did not drain immediately, evaporated. I also was very skeptical of this design, but I will tell you first hand it worked beatifully.

But does anyone know if they have tested for scenarios like this? As I remember, the sentinel is rated for 100m, but have they ever done a flood/recovery test at 100m with the unit? I hope they have since they chose this design... If they did, and the tests went well, I would have no problems in diving this unit, except from the size maybe.

I don't believe any manufacturer, or training agency would test this at 100m. It is just too dangerous there. I train/teach on three different models of rear-mounted CCR's and I am not aware of any that would ask a student to perform a skill like that at any depth beyond 60fsw, let alone an actual flood.

Hope I am not too much off topic

Not off topic at all, I think this is the kind of info that the original post was about.

Regards,

Robin

Amphibiman · 23rd July 2008, 22:24

An additional feature that I was skeptical at first is the auto set point switching. This is really a cool feature. The diver sets the perimeters of high and low and the unit will change automatically based on depth. If the diver doesn't want this there is a very simple override to manual.

As I look at my unit next to my Classic, Mk-15 and rEvo it seems bigger, but it is not really much larger at all. I think the "bigger" perception comes from the HUUUUGGGEEE breathing hoses. Which when you use the unit; that large feeling goes away. The actually unit not look at the hoses is really not that big. Those huge breathing hoses are used for better WOB at whatever depth.

Also, we could start a whole new thread on the argument about effeciency of radial vs. Axial scrubber designs; but the simple fact is the Sentinel Scrubber is incredibly effecient because of the air space around the stack (Just like Randy said.) I would guess it to be more effecient than most radial designs.

What I don't like about the Sentinel is the BC; but hey I make BC's for a living, so I could be a little biased. I don't believe that a trim weight belongs on an air-cell, but that is my opinion. So yes, mine already has a DO aircell installed. Regardless of the aircell; the unit trims out beautifully, and very easily.

Hope this helps,

Robin

17th July 2008, 18:27	#1 (permalink)
aqua orca New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2008 Location: Belgium Posts: 2	feedback on Sentinel hello, I appreciate any feedback on your experiences with the Sentinel. comments on mechanical quality, ease of use, robustness, breathing resistance in currents, thank you in advance aqua orca
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17th July 2008, 20:15	#2 (permalink)
ch3micaldud3 New Member Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Nov 2007 Location: Belgium, Vlaams Brabant Posts: 15	Re: feedback on Sentinel Hi there, Check out the different posts on the Sentinel... That should give you already a pretty good idea about this very beautiful rebreather... As I'm awaiting my course and arrival of my very own Sentinel in September, I'll be reading every post about it Keep those experiences & pictures coming ... __________________ OC Adv Rec Tx Instructor & CC Sentinel Diver
(Online)

18th July 2008, 13:26	#3 (permalink)
Marvintpa Bad knees, matching brain Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: Ontario, Canada Posts: 265	Re: feedback on Sentinel Good luck with your request. For some reason I don't understand, the amount of information and talk about the Sentinel has been surprisingly small - I think there was more talk about it before it was launched. There are a few threads on Rebreather World, but not much. I haven't had mine in current yet so can't comment on that, but overall breathing resistance is very goood. Build quality and ease of use are good. The canister is a little different for packing and inserting, but not bad. The quality of the machining is excellent, and the electronics are some of the best available.
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18th July 2008, 14:31	#4 (permalink)
depth Christian Rasmussen Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 190	Re: feedback on Sentinel Hi I do not dive the sentinel myself, but I have seen it up close and I think it has some very nice features. However, from my point of view I think the design has two major drawbacks: 1. The rebreather is huge! It sticks to far out from the back. 2. Your exhale gas goes directly in to the scrubber, so if you use the sofnolime option, the absorbent will be soaked if you get water in the loop through the mouthpiece. Can anyone shoot a picture at the sentinel besides another Rebreather like the meg? A top down picture will show the size difference.... Just my opinion, hope you can use it... /Christian __________________ I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not............. Last edited by depth : 18th July 2008 at 17:31.
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18th July 2008, 15:01	#5 (permalink)
nigelh New Member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 835	Re: feedback on Sentinel Quote: (Originally Posted by Marvintpa) For some reason I don't understand, the amount of information and talk about the Sentinel has been surprisingly small - I think there was more talk about it before it was launched. Because lots of us are idly reading the manual waiting for ours to come due. I'm October. By about January we should be driving the rest of you mad swapping detail stories and fixes. __________________ nigelh
(Offline)

19th July 2008, 04:20	#6 (permalink)
Mixaddict Always Learning! Current Rebreather/s: Inspiration Vision Evolution Other CCR Dolphin Other Rebreather/s: Inspiration Classic Other CCR Dolphin Join Date: Jan 2006 Location: Draper, Utah USA Posts: 474	Re: feedback on Sentinel Quote: (Originally Posted by depth) 2. Your exhale gas goes directly in to the scrubber, so if you use the sofnolime option, the absorbent will be soaked if you get water in the loop through the mouthpiece. /Christian As a diver and instructor on the Sentinel, I can tell you that water ingress into the scrubber does not seem to be any more of a concern than on OTS counter lungs. The way the unit is designed, it is very simple to flush water through the system. Additionally, the insulation of the canister is some of the best on the market, which keeps the heat at a substantial level. I believe this contributes to the evaporation of water in the scrubber more quickly than a lot of units. During our initial training, one of the students while doing drills, accidentally left his dsv open with the loop out of his mouth at about 20 meters. It floated above his head for 10 or 15 seconds. We were all very anxious after the dive to inspect his scrubber and see how much water was in the bottom on it. To our surprise, there was almost none. A combination of forcing water down through the scrubber and out the OPV in the bottom of the scrubber as well as the heat of the scrubber completely removed the water. It was actually quite amazing. I like the unit a lot. The electronics are top notch. I really don't notice the size of the unit at all, especially in the water. I love the uncluttered chest area. It trims out almost perfectly for me right out of the box. The build quality is wonderful. The service from Delta P has been great. The breathing hoses are VERY long, but when you feel how easy the WOB is, you can put up with long hoses! The BOV is very good. The forced pre-dive checks may seem draconian to some, but I can already tell you from personal experience, that they absolutely force you to pay attention! Part of the thickness of the unit is because of the way the insulating space is around the canister. It is obviously by design, and it simply works. Good canister duration. Good WOB. Good durability. Good performance What else could you ask for? I know, I know, half the size, half the weight and half the price! Of course, with that, you would get half the performance! With many of the same performance features and some improvements from the Oroborous, it really is a VERY nice unit. Try it, you'll like it! Regards, Randy __________________ Randy Thornton (MixAddict) Inspiration, Evolution,Hammerhead & Sentinel CCR Instructor
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20th July 2008, 18:54	#7 (permalink)
Peter M New Member Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2007 Location: Northern Ireland Posts: 52	Re: feedback on Sentinel I've just returned from a weekend of diving on mine, it was a mixed weekend with currents "like being in a washing machine". I had the only Sentinel on the boat and when it sat along side inspirations, twin sets, and singles it didnt seem any "deeper" than anything else and i had six inspo divers looking at it very closely. Dealing with the currents we encounterd didnt pose any more problems than any of the other divers. As for the long hoses i like the as i feel i have more freedom to move my head, just mark them when you get them comfortable. This is my first rebreather and after the initial hicups which Delta P dealt with very quickly it has been really great, I have made a few mods like a longer wing inflation hose and caps to hold the first stages. Electronics wise i am gradually getting used to them being able to use a vr3 is a great help. I can also say that the scrubber doesnt get all that wet as i also left my loop OPEN above my head for approx 10 secs in training and the sorb was basically dry. Last edited by Peter M : 20th July 2008 at 18:57.
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20th July 2008, 19:41	#8 (permalink)
depth Christian Rasmussen Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 190	Re: feedback on Sentinel Quote: (Originally Posted by Mixaddict) The way the unit is designed, it is very simple to flush water through the system. Additionally, the insulation of the canister is some of the best on the market, which keeps the heat at a substantial level. I believe this contributes to the evaporation of water in the scrubber more quickly than a lot of units. Hi Randy The above mentioned sounds plausible but imagine diving at 100m and the shit hits the fan, you lose your dsv and enough water enters the loop to almost completely soak the scrubber. You relocate the dsv and go back on the loop and realizes the unit is flooded causing increased WOB so you decide to dump the water through the OPV. You are now on the loop on a rebreather with a scrubber that might/might not function. If the scrubber is not working you can only hope you have time to realize an incoming CO2 hit and go OC. Just a thought.... But does anyone know if they have tested for scenarios like this? As I remember, the sentinel is rated for 100m, but have they ever done a flood/recovery test at 100m with the unit? I hope they have since they chose this design... If they did, and the tests went well, I would have no problems in diving this unit, except from the size maybe. Hope I am not too much off topic Christian __________________ I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not.............
(Online)

23rd July 2008, 22:07	#9 (permalink)
Amphibiman New Member Current Rebreather/s: Classic Kiss MK 15.X rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Jan 2006 Location: San Diego California Posts: 35	Re: feedback on Sentinel [quote=depth;198924] Hi Randy The above mentioned sounds plausible but imagine diving at 100m and the shit hits the fan, you lose your dsv and enough water enters the loop to almost completely soak the scrubber. You relocate the dsv and go back on the loop and realizes the unit is flooded causing increased WOB so you decide to dump the water through the OPV. You are now on the loop on a rebreather with a scrubber that might/might not function. If the scrubber is not working you can only hope you have time to realize an incoming CO2 hit and go OC. Just a thought.... Hi Christian, I was the student Randy was mentioning. This is my first rebreather that has a BOV. So while performing skills I was going back and forth opening and closing the mouth piece and thought it was closed when I ditched the loop. Anyway, what Randy was trying to say is that a whole-lotta water entered the loop and went straight through the scrubber. If I remember correctly we did an additional 60 minutes after the event and during break-down it was appearent that whatever water did not drain immediately, evaporated. I also was very skeptical of this design, but I will tell you first hand it worked beatifully. But does anyone know if they have tested for scenarios like this? As I remember, the sentinel is rated for 100m, but have they ever done a flood/recovery test at 100m with the unit? I hope they have since they chose this design... If they did, and the tests went well, I would have no problems in diving this unit, except from the size maybe. I don't believe any manufacturer, or training agency would test this at 100m. It is just too dangerous there. I train/teach on three different models of rear-mounted CCR's and I am not aware of any that would ask a student to perform a skill like that at any depth beyond 60fsw, let alone an actual flood. Hope I am not too much off topic Not off topic at all, I think this is the kind of info that the original post was about. Regards, Robin
(Offline)

23rd July 2008, 22:24	#10 (permalink)
Amphibiman New Member Current Rebreather/s: Classic Kiss MK 15.X rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Jan 2006 Location: San Diego California Posts: 35	Re: feedback on Sentinel An additional feature that I was skeptical at first is the auto set point switching. This is really a cool feature. The diver sets the perimeters of high and low and the unit will change automatically based on depth. If the diver doesn't want this there is a very simple override to manual. As I look at my unit next to my Classic, Mk-15 and rEvo it seems bigger, but it is not really much larger at all. I think the "bigger" perception comes from the HUUUUGGGEEE breathing hoses. Which when you use the unit; that large feeling goes away. The actually unit not look at the hoses is really not that big. Those huge breathing hoses are used for better WOB at whatever depth. Also, we could start a whole new thread on the argument about effeciency of radial vs. Axial scrubber designs; but the simple fact is the Sentinel Scrubber is incredibly effecient because of the air space around the stack (Just like Randy said.) I would guess it to be more effecient than most radial designs. What I don't like about the Sentinel is the BC; but hey I make BC's for a living, so I could be a little biased. I don't believe that a trim weight belongs on an air-cell, but that is my opinion. So yes, mine already has a DO aircell installed. Regardless of the aircell; the unit trims out beautifully, and very easily. Hope this helps, Robin
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