Sentinel in Denmark

silent running · 3rd March 2008, 16:58

Quote: (Originally Posted by Drmike)

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.

Yes, if the Sentinal and Boris are both the same measurement at the thickest point, then it's not so bad. But, it did look bigger with the production cowling in place than the prototype. Actually, the Sentinal might have a better drag profile as the scrubber fits down the center so the sides are probably thinner than Boris and the thickest part is behind the head in normal swimming position. Might be more like a slightly bigger CK.

As for a Inspo vs Boris swimability test, I would think that since we are taught to keep our loop at min volume and OTS lungs are made from fabric and never fully expanded underwater(mine are almost collapsed at min volume)their hydro drag would not be as much as a BMCL unit of similar thickness but which is made up entirely of hard plastic or fiberglass.

My experience with BMCL units:

Dolphin/Atlantis-noticeable drag as the cowling is the same thickness all the way accross.

CK-less draggy than Dragers because the thickest part is behind the head.

I thought the stock Prism swam noticably better than these 2. But with a bigger Grey Wolf cowling and back plate, the Prism had a lot more drag and it was only a little bit bigger than stock. So even minor changes in the profile can make a big difference in swimability. Maybe the Sentinal cowling could be trimmed down further, like getting rid of the part over the tanks. I don't see the point of protecting them, unless they are baring the weight, like the Prism cowling does.

PS, thanks Rasmus for posting the nice pictures. -Andy

Captain Nemo · 3rd March 2008, 20:25

Blimey it reminds me of diving with a 15 litre ally cylinder.....

***Decodiver*** · 3rd March 2008, 20:42

Hi Rasmus,

How much weight did you need on the unit in that configuration, you're using a membrane suit I guess?

The weights are strapped behind your neck is that right?

Cheers,

Dave.

cool_hardware52 · 3rd March 2008, 22:07

Quote: (Originally Posted by Drmike)

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

Sounds kinda final. Have you sworn off women?

Tobin

Drmike · 4th March 2008, 02:32

Quote: (Originally Posted by cool_hardware52)

Sounds kinda final. Have you sworn off women?

Tobin

no no no - If I did that who would clean up my crap?

***caveseeker7*** · 4th March 2008, 05:54

Quote: (Originally Posted by cool_hardware52)

Sounds kinda final. Have you sworn off women?

Tobin

No more women!

No less women either!

Nad · 5th March 2008, 19:42

Quote: (Originally Posted by Marvintpa)

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.

Yes, I also think so.
It is not the smaller unit I ever seen but as Mike said at the 100. place is the Look.

Considering that Rasmus, as he said, was invited to help developing training materials for the Sentinel, didn't keep going on with description of the unit.

The cannister is big, bigger than the one of the Inspiration but the performance...wow, It's worth the size, and not just for the WOB.

Nad

RedSeaDiver · 21st June 2008, 13:18

The specs made the Sentinel sound like it was just what I was looking for - until I saw the photos and realised that I would be swimming around with three housed cameras - and a fridge strapped to my back! Damn that thing looks big.

Roobydoo · 21st June 2008, 14:52

Quote: (Originally Posted by RedSeaDiver)

The specs made the Sentinel sound like it was just what I was looking for - until I saw the photos and realised that I would be swimming around with three housed cameras - and a fridge strapped to my back! Damn that thing looks big.

Don't knock it till you have tried it. Underwater, there is no problem whatosever..... I tried one recently and it is fantastic...

RedSeaDiver · 22nd June 2008, 12:46

Quote: (Originally Posted by Roobydoo)

Don't knock it till you have tried it. Underwater, there is no problem whatosever..... I tried one recently and it is fantastic...

OK I will investigate further then. What sort of dives were you doing - reef dives were you do a lot of swimming around or more vertical dives where drag isn't noticed as much?

3rd March 2008, 16:58	#21 (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: 1,740	Re: Sentinel in Denmark Quote: (Originally Posted by Drmike) 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. Yes, if the Sentinal and Boris are both the same measurement at the thickest point, then it's not so bad. But, it did look bigger with the production cowling in place than the prototype. Actually, the Sentinal might have a better drag profile as the scrubber fits down the center so the sides are probably thinner than Boris and the thickest part is behind the head in normal swimming position. Might be more like a slightly bigger CK. As for a Inspo vs Boris swimability test, I would think that since we are taught to keep our loop at min volume and OTS lungs are made from fabric and never fully expanded underwater(mine are almost collapsed at min volume)their hydro drag would not be as much as a BMCL unit of similar thickness but which is made up entirely of hard plastic or fiberglass. My experience with BMCL units: Dolphin/Atlantis-noticeable drag as the cowling is the same thickness all the way accross. CK-less draggy than Dragers because the thickest part is behind the head. I thought the stock Prism swam noticably better than these 2. But with a bigger Grey Wolf cowling and back plate, the Prism had a lot more drag and it was only a little bit bigger than stock. So even minor changes in the profile can make a big difference in swimability. Maybe the Sentinal cowling could be trimmed down further, like getting rid of the part over the tanks. I don't see the point of protecting them, unless they are baring the weight, like the Prism cowling does. PS, thanks Rasmus for posting the nice pictures. -Andy
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3rd March 2008, 20:25	#22 (permalink)
Captain Nemo New Member Current Rebreather/s: Evolution Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Join Date: Oct 2006 Location: End of the known world Posts: 44	Re: Sentinel in Denmark Blimey it reminds me of diving with a 15 litre ally cylinder..... __________________ Look beyond the dark side into the light. Beware of false knowledge; It is more dangerous than ignorance.
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3rd March 2008, 20:42	#23 (permalink)
*Decodiver* Administrator Current Rebreather/s: Megalodon Ouroboros rEvo Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Classic Kiss rEvo Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,164	Re: Sentinel in Denmark Hi Rasmus, How much weight did you need on the unit in that configuration, you're using a membrane suit I guess? The weights are strapped behind your neck is that right? Cheers, Dave. __________________ CCR/OC Trimix Instructor Trainer CCR Training to Mixed Gas in Switzerland, France, UK & Germany on Megalodon/COPIS-Megalodon/KISS/Sport KISS/Ouroboros/rEvo/Inspiration/Evolution/Sentinel www.zerogravitydiving.com Rebreather World Terms & Conditions
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3rd March 2008, 22:07	#24 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 358	Re: Sentinel in Denmark Quote: (Originally Posted by Drmike) hahah, lets put it this way my last girlfriend wasnt born when I married my 1st wife Sounds kinda final. Have you sworn off women? Tobin __________________ www.deepseasupply.com
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4th March 2008, 02:32	#25 (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: 3,062	Re: Sentinel in Denmark Quote: (Originally Posted by cool_hardware52) Sounds kinda final. Have you sworn off women? Tobin no no no - If I did that who would clean up my crap? __________________ 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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4th March 2008, 05:54	#26 (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: 5,280	Re: Sentinel in Denmark Quote: (Originally Posted by cool_hardware52) Sounds kinda final. Have you sworn off women? Tobin No more women! No less women either! __________________ Cheers Stefan Be Water, My Friend - Bruce Lee Sponsor Lou in Race For Life!
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5th March 2008, 19:42	#27 (permalink)
Nad Rebel to the Bone Current Rebreather/s: Ouroboros Other Rebreather/s: Not Bought Yet Inspiration Classic Join Date: Mar 2005 Location: Europe Posts: 924	Re: Sentinel in Denmark Quote: (Originally Posted by Marvintpa) 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. Yes, I also think so. It is not the smaller unit I ever seen but as Mike said at the 100. place is the Look. Considering that Rasmus, as he said, was invited to help developing training materials for the Sentinel, didn't keep going on with description of the unit. The cannister is big, bigger than the one of the Inspiration but the performance...wow, It's worth the size, and not just for the WOB. Nad __________________ The Impossible is often the Untried
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21st June 2008, 13:18	#28 (permalink)
RedSeaDiver New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2007 Location: haulin iron ore in the Aussie outback Posts: 11	Re: Sentinel in Denmark The specs made the Sentinel sound like it was just what I was looking for - until I saw the photos and realised that I would be swimming around with three housed cameras - and a fridge strapped to my back! Damn that thing looks big.
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21st June 2008, 14:52	#29 (permalink)
Roobydoo New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Classic Evolution Sport Kiss Classic Kiss Join Date: Aug 2005 Location: Cayman Islands Posts: 6	Re: Sentinel in Denmark Quote: (Originally Posted by RedSeaDiver) The specs made the Sentinel sound like it was just what I was looking for - until I saw the photos and realised that I would be swimming around with three housed cameras - and a fridge strapped to my back! Damn that thing looks big. Don't knock it till you have tried it. Underwater, there is no problem whatosever..... I tried one recently and it is fantastic... __________________ Who said that..? www.divetech.com for bubbles and no bubbles in the Caribbean
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22nd June 2008, 12:46	#30 (permalink)
RedSeaDiver New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2007 Location: haulin iron ore in the Aussie outback Posts: 11	Re: Sentinel in Denmark Quote: (Originally Posted by Roobydoo) Don't knock it till you have tried it. Underwater, there is no problem whatosever..... I tried one recently and it is fantastic... OK I will investigate further then. What sort of dives were you doing - reef dives were you do a lot of swimming around or more vertical dives where drag isn't noticed as much?
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