Sentinel in Denmark

Drmike · 3rd March 2008, 05:54

I too wish it was smaller - but I wonder, given that none of the small units can pass the CE WOB test that this suggests there may be a correlation?

Personally how a unit looks is of absolutely no concern to me at all.

I dont grab a screwdriver from my tool box and concern myself how attractive that screwdriver is! I only care how well that tool does its job.

Whats important to me (in order is)

1. WOB
2. Scrubber performance
3. Reliability
4. Size
.
.
.
100. Looks

Size of course is important as it can determine how well it does its job if diving where theres a restriction or strong currents. (the reason I have more than one rebreather)

whilst on this subject, It amazes me that people often buy units and yet have no idea at all what the actual tested wob is or how their scrubbers perform at depth. To me the latter two bits of data should be the 1st question asked. I mean you wouldnt buy a car without checking how it performs (gas consumption, top speed etc) If the mnf cant tell you then he doesnt know or its bad - either way that should worry you enough not to buy a unit!

Do a poll here and see how many know the WOB of their life support systems or new it before they bought it! (actual tested wob not percieved as we know that means squat)

Its going to be of very little consolation how small and beautiful a unit is as your suffering from a retained CO2 hit at depth brought on through poor WOB or a scrubber breakthrough brought on by poor scrubber performance.

opps - a little rant - low blood sugar - going for lunch now

silent running · 3rd March 2008, 08:18

Quote: (Originally Posted by Drmike)

I too wish it was smaller - but I wonder, given that none of the small units can pass the CE WOB test that this suggests there may be a correlation?

Personally how a unit looks is of absolutely no concern to me at all.

I dont grab a screwdriver from my tool box and concern myself how attractive that screwdriver is! I only care how well that tool does its job.

Whats important to me (in order is)

1. WOB
2. Scrubber performance
3. Reliability
4. Size
.
.
.
100. Looks

Size of course is important as it can determine how well it does its job if diving where theres a restriction or strong currents. (the reason I have more than one rebreather)

whilst on this subject, It amazes me that people often buy units and yet have no idea at all what the actual tested wob is or how their scrubbers perform at depth. To me the latter two bits of data should be the 1st question asked. I mean you wouldnt buy a car without checking how it performs (gas consumption, top speed etc) If the mnf cant tell you then he doesnt know or its bad - either way that should worry you enough not to buy a unit!

Do a poll here and see how many know the WOB of their life support systems or new it before they bought it! (actual tested wob not percieved as we know that means squat)

Its going to be of very little consolation how small and beautiful a unit is as your suffering from a retained CO2 hit at depth brought on through poor WOB or a scrubber breakthrough brought on by poor scrubber performance.

opps - a little rant - low blood sugar - going for lunch now

Good points Mike, low blood sugar or not. I totally agree with your list of priorities, same as mine. And you're right, my beginner ass would never have had any idea about how important WOB was and low it was on the Prism if Peter Readey hadn't told me and then shown me the USN tests

Although it may seem that people are focusing on aesthetics, maybe some of those who think "it's too big" are reacting instinctually. Think about it this way: you could have a CCR that had a fan pushing gas around the loop with 0 WOB in all positions and a giant scrubber with a heating element around it, but the thing would probably be the size of a coffin and about as good for your health in a high workload situation.

I'm not saying that the Sentinal is too big-I have no firm opinion until after I've dived one AND looked at the WOB tests. But at first glance, I am surprised to see that it may be thicker than Boris front to back, which can't be good in a high work load situation and could negate any WOB advantage it has due to the different CL placement. The proportions of a unit, and particularlly the scrubber around which any good unit is built, are IMHO, closer to an art than a science and have more to do with exactly how the unit will be used than say, un-manned testing.

IMHO, it's a very difficult and thankless task trying to re-invent the wheel, but I'm glad somebody is, otherwise there would be no progress at all...

Drmike · 3rd March 2008, 08:39

Quote: (Originally Posted by silent running)

I'm not saying that the Sentinal is too big

i think all rbs are too big. Id really like one the size of a matchbox please

You make a valid point re: size (or drag) balancing against WOB

Every now and then when Im strapping on Boris I feel a sense of its size and consider it too big. But at times when im using the unit for the type of diving its designed for and I look at what my OC buddies are wearing (huge heavy steel twins plus stages) I feel much better. Theres far less/no size disparity then. Of course if your using a unit capable of diving to 200m+ on a dive to 20m then you can steal a glance at your buddy diving his sports kiss and feel jealous

IIRC the Sentinel is supposed to be same thickness as Boris? Think there was a chart someplace.

But then theres the whole 'no OTS CL drag and additional size issue' to contend with. When considering the swimability (is that a real word?) of BMCL and OTS units.

What is drag coef for Sentinel compared to say Inspo?

If you include the CLs (why wouldnt you?) the overall profile is very similar so drag should be similar I presume.

Be interesting to test this out and know for sure. Just like non lab based WOB tests though its very subjective.

richc · 3rd March 2008, 11:59

Quote: (Originally Posted by Drmike)

Theres far less/no size disparity then. Of course if your using a unit capable of diving to 200m+ on a dive to 20m then you can steal a glance at your buddy diving his sports kiss and feel jealous

If you want an idea of (not!) using the right tool for the job - I took my Boris to the Red Sea to clock up some hours before Mod3. I got some interesting looks from people diving single 12's! On the briefing on day 1 the dive guides said there was no time limit to dives as long as everyone was back to 6m when they were at 80 bar. I stuck my hand up and asked if that included me. They said yes. For dive 2 a new rule for rebreathers was introduced......

Rich

***caveseeker7*** · 3rd March 2008, 12:43

Gobfish1 · 3rd March 2008, 13:00

hay Mike

hope you dont pick you're wimmin the same way ,,, as long as it;s fit for the job ,,,

ok some may say its fit for the job , but would you ,,,

Drmike · 3rd March 2008, 13:30

Quote: (Originally Posted by Gobfish1)

hay Mike

hope you dont pick you're wimmin the same way ,,, as long as it;s fit for the job ,,,

ok some may say its fit for the job , but would you ,,,

hahah, lets put it this way my last girlfriend wasnt born when I married my 1st wife

Why? because I can

and canT do a fatty as they wont fit in my new Lotus

Gobfish1 · 3rd March 2008, 13:43

Quote: (Originally Posted by Drmike)

hahah, lets put it this way my last girlfriend wasnt born when I married my 1st wife

Why? because I can

and canT do a fatty as they wont fit in my new Lotus

funny that as when i was out in singapore my bird was half my age ,,, ha ha

i can lend you my

,,

Marvintpa · 3rd March 2008, 15:08

Although the last of the photos does look pretty bad as to the size of the unit, I'm not going to worry about it too much because there's likely a little wide angle lens distortion to that photo. My guess is it was taken with a 10.5mm lens (or something close to it) and objects closer to the lens will look larger.

Ilikerisk · 3rd March 2008, 15:45

If it really is that large and ungainly and oddly laid out, its very disappointing.

3rd March 2008, 05:54	#11 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Sentinel in Denmark I too wish it was smaller - but I wonder, given that none of the small units can pass the CE WOB test that this suggests there may be a correlation? Personally how a unit looks is of absolutely no concern to me at all. I dont grab a screwdriver from my tool box and concern myself how attractive that screwdriver is! I only care how well that tool does its job. Whats important to me (in order is) 1. WOB 2. Scrubber performance 3. Reliability 4. Size . . . 100. Looks Size of course is important as it can determine how well it does its job if diving where theres a restriction or strong currents. (the reason I have more than one rebreather) whilst on this subject, It amazes me that people often buy units and yet have no idea at all what the actual tested wob is or how their scrubbers perform at depth. To me the latter two bits of data should be the 1st question asked. I mean you wouldnt buy a car without checking how it performs (gas consumption, top speed etc) If the mnf cant tell you then he doesnt know or its bad - either way that should worry you enough not to buy a unit! Do a poll here and see how many know the WOB of their life support systems or new it before they bought it! (actual tested wob not percieved as we know that means squat) Its going to be of very little consolation how small and beautiful a unit is as your suffering from a retained CO2 hit at depth brought on through poor WOB or a scrubber breakthrough brought on by poor scrubber performance. opps - a little rant - low blood sugar - going for lunch now __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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3rd March 2008, 08:18	#12 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,810	Re: Sentinel in Denmark Quote: (Originally Posted by Drmike) I too wish it was smaller - but I wonder, given that none of the small units can pass the CE WOB test that this suggests there may be a correlation? Personally how a unit looks is of absolutely no concern to me at all. I dont grab a screwdriver from my tool box and concern myself how attractive that screwdriver is! I only care how well that tool does its job. Whats important to me (in order is) 1. WOB 2. Scrubber performance 3. Reliability 4. Size . . . 100. Looks Size of course is important as it can determine how well it does its job if diving where theres a restriction or strong currents. (the reason I have more than one rebreather) whilst on this subject, It amazes me that people often buy units and yet have no idea at all what the actual tested wob is or how their scrubbers perform at depth. To me the latter two bits of data should be the 1st question asked. I mean you wouldnt buy a car without checking how it performs (gas consumption, top speed etc) If the mnf cant tell you then he doesnt know or its bad - either way that should worry you enough not to buy a unit! Do a poll here and see how many know the WOB of their life support systems or new it before they bought it! (actual tested wob not percieved as we know that means squat) Its going to be of very little consolation how small and beautiful a unit is as your suffering from a retained CO2 hit at depth brought on through poor WOB or a scrubber breakthrough brought on by poor scrubber performance. opps - a little rant - low blood sugar - going for lunch now Good points Mike, low blood sugar or not. I totally agree with your list of priorities, same as mine. And you're right, my beginner ass would never have had any idea about how important WOB was and low it was on the Prism if Peter Readey hadn't told me and then shown me the USN tests Although it may seem that people are focusing on aesthetics, maybe some of those who think "it's too big" are reacting instinctually. Think about it this way: you could have a CCR that had a fan pushing gas around the loop with 0 WOB in all positions and a giant scrubber with a heating element around it, but the thing would probably be the size of a coffin and about as good for your health in a high workload situation. I'm not saying that the Sentinal is too big-I have no firm opinion until after I've dived one AND looked at the WOB tests. But at first glance, I am surprised to see that it may be thicker than Boris front to back, which can't be good in a high work load situation and could negate any WOB advantage it has due to the different CL placement. The proportions of a unit, and particularlly the scrubber around which any good unit is built, are IMHO, closer to an art than a science and have more to do with exactly how the unit will be used than say, un-manned testing. IMHO, it's a very difficult and thankless task trying to re-invent the wheel, but I'm glad somebody is, otherwise there would be no progress at all...
(Offline)

3rd March 2008, 08:39	#13 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Sentinel in Denmark Quote: (Originally Posted by silent running) I'm not saying that the Sentinal is too big i think all rbs are too big. Id really like one the size of a matchbox please You make a valid point re: size (or drag) balancing against WOB Every now and then when Im strapping on Boris I feel a sense of its size and consider it too big. But at times when im using the unit for the type of diving its designed for and I look at what my OC buddies are wearing (huge heavy steel twins plus stages) I feel much better. Theres far less/no size disparity then. Of course if your using a unit capable of diving to 200m+ on a dive to 20m then you can steal a glance at your buddy diving his sports kiss and feel jealous IIRC the Sentinel is supposed to be same thickness as Boris? Think there was a chart someplace. But then theres the whole 'no OTS CL drag and additional size issue' to contend with. When considering the swimability (is that a real word?) of BMCL and OTS units. What is drag coef for Sentinel compared to say Inspo? If you include the CLs (why wouldnt you?) the overall profile is very similar so drag should be similar I presume. Be interesting to test this out and know for sure. Just like non lab based WOB tests though its very subjective. __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 3rd March 2008 at 08:41.
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3rd March 2008, 11:59	#14 (permalink)
richc New Member Current Rebreather/s: Ouroboros Other Rebreather/s: Join Date: Nov 2005 Location: Hove actually Posts: 40	Re: Sentinel in Denmark Quote: (Originally Posted by Drmike) Theres far less/no size disparity then. Of course if your using a unit capable of diving to 200m+ on a dive to 20m then you can steal a glance at your buddy diving his sports kiss and feel jealous If you want an idea of (not!) using the right tool for the job - I took my Boris to the Red Sea to clock up some hours before Mod3. I got some interesting looks from people diving single 12's! On the briefing on day 1 the dive guides said there was no time limit to dives as long as everyone was back to 6m when they were at 80 bar. I stuck my hand up and asked if that included me. They said yes. For dive 2 a new rule for rebreathers was introduced...... Rich
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3rd March 2008, 12:43	#15 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,418	__________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.'!"
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3rd March 2008, 13:30	#17 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Sentinel in Denmark Quote: (Originally Posted by Gobfish1) hay Mike hope you dont pick you're wimmin the same way ,,, as long as it;s fit for the job ,,, ok some may say its fit for the job , but would you ,,, hahah, lets put it this way my last girlfriend wasnt born when I married my 1st wife Why? because I can and canT do a fatty as they wont fit in my new Lotus __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 3rd March 2008 at 13:33.
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3rd March 2008, 15:08	#19 (permalink)
Marvintpa Bad knees, matching brain Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: Ontario, Canada Posts: 250	Re: Sentinel in Denmark Although the last of the photos does look pretty bad as to the size of the unit, I'm not going to worry about it too much because there's likely a little wide angle lens distortion to that photo. My guess is it was taken with a 10.5mm lens (or something close to it) and objects closer to the lens will look larger.
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3rd March 2008, 15:45	#20 (permalink)
Ilikerisk New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2007 Location: New York Posts: 48	Re: Sentinel in Denmark If it really is that large and ungainly and oddly laid out, its very disappointing.
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