Diving Performance - Beyond Drag (article Series And Discussion)

[fjpatrum]

@ronscuba the handful of drift dives I've done didn't go that way. The boat watched bubbles and looked for SMBs to pick up divers. No one tried to "stay together". This was only at two different locations, though, and both in Florida so maybe it's different than other places doing drifts. People that wanted to "fight current" used reef hooks and that didn't require any effort or cause them to blow through significantly more gas than just drifting does. Using different gear and kicking against the current most definitely would.

I have no problem with improving diving efficiency; I think it is a great goal. I just don't believe trying to justify it by implying that divers need to swim at 3-5 knots is the right approach. Doing so negates the valid justifications that are actually out there. Focus on air consumption and bottom time over speed. Focus on "simplicity" as a result of said efficiencies (if possible) and stop trying to tell people they're going to die. History has proven that is simply not accurate for millions of divers. I suspect, however, that people doing the research have found that it's a significant cost factor for very slight incremental improvements in bottom time and air consumption, though. In this particular instance, I believe @REVAN just has different diving goals than most people and doesn't recognize the niche factor of his own style of diving.

In the end, people like me will adopt some of what people like @REVAN are trying to accomplish. Not all but some. That is, as I see it, a win for both of us.

 

[REVAN]

Part 3 has been posted: Diving Performance, Beyond Drag - Part 3 – DeeperBlue.com

To answer your requirements question, I would take a reasonable average of the currents at say, 90% of dive sites world wide during "peak" season (for each site) as the more realistic current requirements for a diver. I would then consider that there are very few divers operating "independently in the open ocean" and factor that into my estimates. (Most recreational divers in the "open ocean" have some sort of surface support, whether it's a buoy, a boat, or something else.) My complete guess is the number is closer to 1.5-2 knots than 3-5 knots but it is, admittedly, a guess.

So, we are actually in agreement that the current gear and diving techniques provides inadequate mobility for doing what divers are doing. It appears we disagree on what level of mobility is needed, simply because we disagree on the types of dives the gear should be allowing divers to attempt. You are looking at this from the perspective of limiting your diving to locations that have already been chosen for having benign conditions. I am looking at this from the perspective that I want to open up most of the oceans diveable depths for exploration, not just the small fraction that is currently accessible to divers. That is a fair difference of opinion, and I think both are valid.

Not everyone has the same goals in diving, but I think most people who try diving are drawn to it for the sense of exploration and adventure. Once they discover recreational scuba diving is only geared toward conducting dives in a few locations that have been dove by thousands of others, they tend to lose interest and quit diving. I think this is likely the main reason why the attrition rate is so high among new divers. If divers had the freedom to go trailblazing underwater, it would be more interesting and better hold that element of exploration they crave.

 

[fjpatrum]

I don't think I'd say we're in agreement that current gear is a limitation on current dive options, @REVAN, but I can recognize improvement as a good thing. I've always said I believe your motivations are good I just don't believe there's much of a market for the type of diving you're using as your justification. Most divers simply don't want to "fight current" in any way shape or form that would necessitate "opening up most of the ocean's diveable depths". Primarily because most of the ocean doesn't have pretty fish, coral, or wrecks. People dive to see things not empty water. You might open up a couple hundred more dive sites but the draw would still be incredibly limited, I believe.

People don't dive in a "few locations". They dive all over the world. You could arguably dive every day of your adult life and still not dive all the currently available dive locations in the world. Most people don't lack for locations to dive, they lack time and money to dive.

All that said, niche markets have a place as well and if you open up a niche market some amount of that will definitely bleed into the mainstream of diving. That's a good thing, in my opinion.

As far as trail blazing under water, that didn't draw people in the 60s and 70s any more than it will now. Trailblazers really aren't the mainstream and they probably shouldn't be. People quit diving for lots of reasons, the least of which (in my opinion) is boredom from diving. Most commonly it's time and other activities. Diving doesn't have to be expensive but there's no way to make it take less time. A day of diving is just that, a whole damn day, for most people. Most other hobbies can be done in a few hours and often times require less gear and have more "general appeal". Add the cost factor, whatever it is, whether filling tanks/servicing gear or just paying to rent all your stuff and suddenly the 8 hours of prep and cleanup for an hour and a half of seeing things simply doesn't balance well for a lot of people.

 

[REVAN]

There is an island in Mexico I have dove many, many times (Isla San Pedro Nolasco). There are 3 places on the island that are safely accessible to scuba divers, the rest of it, a bad idea due to strong currents. We have probably explored less than 5% of what is there. I've always found it frustrating having to turn back where the current creates a barrier to my exploration if I attempt to leave one of these sheltered areas.

 

[ronscuba]

Part 3 was interesting and written a little more polite. Your posts still have wording that conflicts.

"So, we are actually in agreement that the current gear and diving techniques provides inadequate mobility for doing what divers are doing. It appears we disagree on what level of mobility is needed, simply because we disagree on the types of dives the gear should be allowing divers to attempt."

Current scuba gear and technique is adequate for what current scuba divers are doing. But, it may be inadequate for the types of dives you want to do.

I like your passion and see you as a pioneer thinking outside of the box to make divers swim faster and more efficient. Some of your ideas are too exotic and extreme for main stream scuba divers to adopt. Monofins and tank cones are not going to happen anytime soon for standard scuba diving.

 

[REVAN]

Monofins and tank cones are not going to happen anytime soon for standard scuba diving.

That is why the monofin was not a part of this project. It may work very well for me, but the masses are simply not ready for anything like that. I was actually surprised when you brought up the subject on using the dolphin kick technique while scuba diving. That you brought up the subject was the only reason I talked about the monofin here. For me, that is an old project. This article is about what's new.

However, I don't see why there should be the resistance to using the fairing elements for lowering the drag of the scuba equipment. It adds maybe 2 minutes time setting up the gear. After that you basically dive it like normal except that the incremental drag is almost not there. From a user perspective, it changes a lot less than switching to a sidemount rig, which is a trend that is growing in popularity. The fairings are almost a non-issue from a user perspective. I'd like to know more details of your thoughts on this subject.

 

[Monofin]

It would appear that fjpatrum and REVAN are at opposite ends of the spectrum. That is OK. Some like to stroll in the park and others like to take a hike. To each his own and on their own schedule. Most will do some of each if equipment change is not required. I frequently hike with the same shoes I wear for a stroll but I still own a pair of hiking boots.

People are naturally resistant to change, more so when new equipment is required, and even more so when a new style of equipment is introduced. Example: Snow boards were a hard sell (and even banned is some areas) in the beginning. Now a trip to the slopes with two skies tends to put you into the old folks category.

I had an eye opening experience in another field when weight shift control trikes were new. As a fixed wing airplane and glider pilot I did not understand why anyone would want to fly one of those apparently inferior aircraft. Several years later when officially introduced and trained as a trike pilot my first thought was “Wow, what have I been missing all these years?” Not for everyone but for some there is nothing like it.

If you are wreck diving, cave diving or just into still photography a mono fin is probably not on your want list. But, it appears that divers in general are always looking for more efficient propulsion. I have to ask fjpatrum why he bothers with fins at all when scuba diving. Many free divers dive without fins. The fact that you and virtually all other scuba divers use diving fins should make it obvious that propulsion and propulsive efficiency is important. The issue here is where you draw the line between good enough and not worth the trouble. That is a good question and deserves consideration and a good answer. Not all will have the same answer. This is apparent from the wide variety of fins on the market as well as the diverse comments in these posts.

I am pleased that this series of articles is opening that discussion as I agree it is an interesting and important subject.

 

[ronscuba]

.....
However, I don't see why there should be the resistance to using the fairing elements for lowering the drag of the scuba equipment. It adds maybe 2 minutes time setting up the gear. After that you basically dive it like normal except that the incremental drag is almost not there. From a user perspective, it changes a lot less than switching to a sidemount rig, which is a trend that is growing in popularity. The fairings are almost a non-issue from a user perspective. I'd like to know more details of your thoughts on this subject.

IMHO, change in the general scuba industry happens in baby steps. The bigger the change, the longer it will take, if it happens at all. Tank cones are not a change, but something totally new and very specialized. Cost and convenience will be a big factor. Is the benefit worth the additional cost and inconvenience to install and carry ?

Current trends that can increase scuba speed and efficiency are utilizing gear and setups already being used in other types of diving. Streamlining hose routes, smaller wings, freedive fins, BP/W, carrying minimal items.

Speaking of fins, freediving already has open heel long fins and removable blades. They could easily market towards scuba. Offer more models of open heel long fins. Offer low priced full foot scuba fin that allows switching to a long blade. I am really surprised Cressi is not offering this.

What about rec BCD's adopting tech's improved ways to store and carry secondary items. Tech divers have a way to carry flashlights and SMB that minimizes drag. Lights are worn and tightly secured to shoulder straps. SMB is in a pocket at the bottom of the plate totally out of the water stream.

Wing manufacturers. In addition to smaller, what about hydrodynamics of wing shape both inflated, deflated and how the wing secures to the plate ? The perimeter of the wing is not secured to anything, allowing it to flop around. Is this causing any meaningful turbulence and drag ?

 

[REVAN]

IMHO, change in the general scuba industry happens in baby steps.

I agree, that is why I made the system shown in Part 3. This is the baby step. Keep everything basically the same, but make it more efficient. Tackling the larger problem of 3 knot cruise is going to require architectural changes to the equipment configurations and will be too large a step for most people to comprehend.

Cost and convenience will be a big factor. Is the benefit worth the additional cost and inconvenience to install and carry ?

That is one of the benefits of getting the mobility high enough. It can potentially save you a lot of money by eliminating one of the most expensive pieces of diving gear that divers tend to not properly account for, the boat. For those that operate on the cheap and dive from a kayak, or similar, a 3 to 5 knot system could replace it with a far more convenient operating process. Not all, but many dive sites that are presently only accessible with a $100+ boat ride could be reached just by swimming to it.

In addition to smaller, what about hydrodynamics of wing shape both inflated, deflated and how the wing secures to the plate ? The perimeter of the wing is not secured to anything, allowing it to flop around. Is this causing any meaningful turbulence and drag ?

Yes. I really don't like using BCs. When I do use a BC, I use my DiveRite TransPack, but I tie the edges of the wing to the sides of my harness with bungee cord to keep it from floating free. It makes it like a hybrid BC halfway between a wing and a jacket style setup. It helps.

 

[wetb4igetinthewater]

@REVAN, do you have a better pic of the cone on top of the tank? What is the theoretical improvement of just drag due to the tank using the cone?