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