Diving Performance - Beyond Drag (article Series And Discussion)

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The solution must take a more radical 'whole diver' system level approach to streamlining and propulsion.
Quick Update:

I just had a successful pool test of a partially completed kit to achieve a 3 knot cruise. There is almost a strange eeriness to gliding through the water so easily. It only takes 4 to 6 fin kicks to cross the 20 meter pool depending on how fast I feel like going. This pool is really too small to get a good feel for what it will be like when unrestrained. It will be exciting to get it into open water and see how it behaves, and especially if I can get some of the other supporting system features incorporated. :)
 
Quick Update:

I just had a successful pool test of a partially completed kit to achieve a 3 knot cruise. There is almost a strange eeriness to gliding through the water so easily. It only takes 4 to 6 fin kicks to cross the 20 meter pool depending on how fast I feel like going. This pool is really too small to get a good feel for what it will be like when unrestrained. It will be exciting to get it into open water and see how it behaves, and especially if I can get some of the other supporting system features incorporated. :)
Video please if you get a chance.
 
Video please if you get a chance.

I'm not ready to go public with it yet, as it is presently a partially completed kit and I don't know how it will all wash out in the end. As such, I haven't decided if I I'm going to apply to protect any IP with the new tech. It may have been better to not say anything at all, but I was just a little too excited after the pool test for that to happen.
:yeahbaby:
If all goes well, I'm hoping to have the major functions integrated for diving the kit this summer. I'm going to try to get to some OW as soon as possible to try its present functionality to see how it all feels (maybe time to start planning a trip to Hawaii). After that, I'll have a much better understanding of how close or far I am from my goal of having a practical and efficient scuba kit for recreational diving.
 
Come to California. Then you can try it out in a cold water environment with drysuit or thicker exposure protection! ;-)
 
Come to California. Then you can try it out in a cold water environment with drysuit or thicker exposure protection! ;-)
I expect the final performance test will be conducted at the Tahoe Benchmark race track. It's about the only place I can think of that's set up for collecting accurate data.
 
I got into some open water with the new kit last weekend. Conditions were terrible, bad visibility and cold (only 60 F on the bottom), but at least there was no current, so that will not interfere with the perceived speeds as captured on video. I had a chest mounted camera to video of the swim. It's not good video, but it is what it is. At least it shows some perspective of the swimming effort and speeds.

I had several problems this first time out. Before trying for more OW testing, I'll need to go back and change some things. So, I've got some work to do before I proceed toward further development to complete the intended function, as the current partial function isn't really all there. At this point all I can say for sure is that it is really efficient, and that makes it fast. I'm pretty sure I was exceeding 4 knots during some parts of the video, and that's not even maximum effort (note the fairly normal breathing rate).


YouTube Text

Open water testing the Nekton CFM80 streamlined scuba kit with a DOL-Fin Orca2 Monofin for propulsion:

This open circuit scuba kit uses a standard aluminum 80 cubic foot scuba tank. Through aggressive streamlining and a highly efficient monofin for propulsion, this system cruises at speeds exceeding 3 knots. It does this without batteries or motors and with a sustainable level of effort that is equivalent to walking. The Nekton CFM80 is an incomplete prototype and we are not showing any details of the kit at this time, but the swimming performance can clearly be seen to be much, much faster than the typical scuba diver, and compared to DPV systems this is extremely quiet (stealth in both EM and acoustic signatures).

Between the equipment streamlining and improved thrust efficiency of the monofin, this kit is presently estimated to achieve an overall hydrodynamic swimming efficiency of approximately 20 to 25 times greater than a typical recreational scuba diver. This increased efficiency results in speeds that are about 3 times faster than typical scuba diver swimming speeds for a given level of effort. Coupled with a closed-circuit rebreather for endurance, instead of an open circuit scuba tank (as is being used here), a diver could reliably cover a distance of over 12 nautical miles in a 4 hour dive interval.

The Nekton CFM80 is presently just an R&D project. However, the diver is using a DOL-Fin Orca Mk-2 Monofin from Smith Aerospace Corp. The Orca monofin is a fully developed and commercially available product.

More testing to follow as engineering development continues....
 
I came across this in an article. It looks like the Nekton CFM80 may be bucking up against world record speeds for human powered submarines in the one person, non-propeller driven category.

"Submarine race leaders praised the innovation of a new one-person submarine, OMER6, also from the Quebec team, which had a radical propulsion system utilizing oscillating wings on each side of the forward fuselage. This submarine shattered the previous non-propeller design speed record by achieving 4.642 knots. Powering OMER6 was Nicolas Tardif."​
 
In more searching I found this in an article from July 2016, a year more recent than the other article.

“The International Submarine Races organization (USA) confirmed that the record for the human powered one person, non propeller class was 4.90 knots."
It didn't say what sub set that 4.9 knot record. I haven't found an official on-line repository for the current records anywhere, so I'm trying to piece it all together from various news articles.

Anyway, I'm not actually trying to beat any human powered submarine records. I just want to make something that works well. I don't think what I'm making could even be classified as a "human powered submarine". It's too much diver and not an enclosed submarine. I just thought it was an interesting benchmark to see what has been done by others who are trying to be the fastest.
 

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