Halcyon pocket shorts?

[boulderjohn]

Dive-xtras makes the X-shorts, the only ones I was really aware of. Because wetsuits are generally rather impermanent, I have glued the same set of Halcyon pockets on a succession of 3mm suits.

X-Shorts (S) - X Shorts - Dive Xtras

I use these, and they work fine.

I don't do a lot of wet suit diving without them, but when I do I do feel as if I have less drag. Perhaps it is similar to the placebo effect.

 

[Jaydubya]

The drag difference is noticeable to me. The bigger the pockets the bigger the drag. The faster the flow the bigger the drag.

In flow you really want to minimize the cross-sectional area that the water is pushing against.

It makes sense when you consider the fluid mechanics involved...

Newton's first law has

F = dP/dt

In this case P is directly proportional to the cross-sectional area of the pockets exposed to the flow and directly proprtional to the square of the velocity of the flow. Double the pocket size- double the drag. Double the flow- quadruple the drag.

Of course things are a bit more complicated than that but I think it's the essence of modeling the problem.

 

[ucfdiver]

The drag difference is noticeable to me. The bigger the pockets the bigger the drag. The faster the flow the bigger the drag.

In flow you really want to minimize the cross-sectional area that the water is pushing against.

It makes sense when you consider the fluid mechanics involved...

Newton's first law has

F = dP/dt

In this case P is directly proportional to the cross-sectional area of the pockets exposed to the flow and directly proprtional to the square of the velocity of the flow. Double the pocket size- double the drag. Double the flow- quadruple the drag.

Of course things are a bit more complicated than that but I think it's the essence of modeling the problem.

Not really--
-Your shoulders have already broken the water flow
-The pockets lay (mostly) flat when they're not full

 

[danvolker]

Not really--
-Your shoulders have already broken the water flow
-The pockets lay (mostly) flat when they're not full

This is actually a thread I would have an interest in "developing" a little....
I do absolutely believe that our shoulders break the water flow---I have experienced how pockets on BC's in the 80's created far more drag than thigh pockets--which were a hot ticket in the early 90's on wetsuits for spearfisherman.

But I have to ask....James, do you "experience" the major, incredibly annoying drag of a Drysuit, or is this just the dramatic difference between diving Cave and diving Palm Beach--very different issues causing very different solutions?

With a freedive wetsuit on, I can actually enjoy dives off Palm Beach that are very hard to do with a drysuit on....Of course, there are a few months out of each year where the thermal uselessness of the wetsuit puts me back in the drysuit, and then I actually have to plan my dives differently, due to the major differences in how cross current traverses or stopping will become problematic.

In the future.......
There is a company called Thermalution...they have an electrically heated undershirt...when it works( when there is no problem with the controler switch), this keeps you very warm in a high tech /non-bouyant exposure suit down to maybe 72 degree water..maybe.... The biggest problems for this now are the controller switches are unreliable on the ones we have tried...and for Cave, duration may mean more thermal insulation would be needed for many hours of low workload diving( generating little core body temp by workload) .... but this direction for hour long dives in ocean, in big drift currents, is very interesting to me.....If they could just make the Thermalution shirts work, then it would be all about finding the best compormise for thermal insulation and slick-no drag surface in a non-boyant exposure suit. When this happens, my $3500 DUI suit will be garbage to me

 

[ucfdiver]

But I have to ask....James, do you "experience" the major, incredibly annoying drag of a Drysuit, or is this just the dramatic difference between diving Cave and diving Palm Beach--very different issues causing very different solutions?

I don't get what you're asking. In cross/90degree current, your legs would have broken the water flow that hit's the pockets. If you're going head on, your shoulders break it. Unless teh flow is coming UP/DOWN, I don't see any direction which your pockets add drag that wasn't already there.

 

[danvolker]

I don't get what you're asking. In cross/90degree current, your legs would have broken the water flow that hit's the pockets. If you're going head on, your shoulders break it. Unless teh flow is coming UP/DOWN, I don't see any direction which your pockets add drag that wasn't already there.

You will need to go on a dive with Bill and me

I have some places in mind, ideal to showcase what I am talking about.....if you don't feel the drag, then I will help you publish your E-Book on how to use a dry suit and pockets the right way

 

[ucfdiver]

You will need to go on a dive with Bill and me

I have some places in mind, ideal to showcase what I am talking about.....if you don't feel the drag, then I will help you publish your E-Book on how to use a dry suit and pockets the right way

You should check your facebook messages more often-- I asked about a dive one weekend and got ignored

 

[danvolker]

You should check your facebook messages more often-- I asked about a dive one weekend and got ignored

Sorry...I sometimes go over 3 weeks without looking at Facebook.....

I will PM you my email address....my phone gets email, so this is going to get me instantly, pretty much any time

 

[Scott L]

You will need to go on a dive with Bill and me

I have some places in mind, ideal to showcase what I am talking about.....if you don't feel the drag, then I will help you publish your E-Book on how to use a dry suit and pockets the right way

Never mind me as my dive gear grows dustier by the day!!!

By the way, have you ever owned a custom suit from Wetwear? I seem to be able to dive in the cold months with their 5mm suit.

 

[guyharrisonphoto]

Dan, check out the mares isotherm 6.5mm semi-dry wetsuit. I just got one and it is really nice. The snug fit and flexibility of a wetsuit and REALLY warm. I took it to crystal river to dive with the manatees in water that was 65 to 72, air temp mid to high 30s, and stayed in 2.5 hours and could have done two hours more, I think, without getting cold. Swam against the current of Three Sisters (I know, not near what we do in Palm Beach) and did not notice any excessive drag. Did a lot of photo shooting, maneuvering, helicopoter, back and frog kicking, lots of arm and leg movement, and felt very flexible. Contruction is first rate. It uses a real drysuit zipper and has double skin seals everywhere. Water simply does not flush through this suit, and my torso actually stayed dry (or just slight damp from condensation). Only downside, it is a back shoulder zip so you need someone to zip youi in and out, but for us "team" divers that is not an issue.

I mention this because they are on sale right now in a lot of places. I think Mares might be discontinuing them. $600 retail, but I got mine for $200, including a matching dry hood. It is an amazing buy right now.