Force Fin review by a die hard Jet Fin user.

[deco_martini]

not really, the SD-1 is a flat paddle type blade, and because of that they work really easily on the surface. The similarities with the standard FF is the high grade of polyurethane and the foot pocket. Really the SD-1 is basically the Force Fin version of the Jet fin, finally someone improved Jet instead of just cloning it and all of its problems.

Again here the urethane gives the fin longevity and performance (rebound or snap) that really lets the fin move your forward.
And although the foot pocket looks very different, it still harness the foot and the leg muscles in the same manner.

Thanks. Sounds like an interesting fin. One of the things that gave me hesitation about FF was the surface swimming profile of the classic and pro since I am known to snorkel after dives. That and get lost and have to swim long ways back to boats on the surface.

DA Aquamaster's post made me think of one more thing.

Some computer programmers won't use anything an IBM keyboard. Other keyboards are too "mushy". The tactile feedback they expect to get from a keyboard due to their prior use of an IBM keyboard create an unfavorable opinion of any other keyboard they try.

So, is DA Aquamaster really finding a lack of torque or is it just a feedback issue? How does someone like DA test the fin to figure out if his issue is real or memorex?

 

[meesier42]

So, is DA Aquamaster really finding a lack of torque or is it just a feedback issue? How does someone like DA test the fin to figure out if his issue is real or memorex?

its nearly impossible unless you are truly unbiased going in and even then you have to overcome the problems of muscle memory. As every different fin requires slightly different muscle technique and such, not to mention the mental aspect of it of the bias. Even if the normal measurements (static thrust, straight line speed) show that the fins were dead equal in performance, that doesn't even begin to assess the other factors of ergonomics, V(dot)O2, lactic acid build up and transport, over-use injuries, fatigue.

in lots of testing that I have done over the last 10 years, I have seen exercise theory in full effect. The truth is simple, when you introduce a new exercise to a person they are not going to be very good at doing it, but with practice their muscles become very efficient at it. I am sure most of use have experienced this weight lifting, as we do more and more bench presses it becomes harder and harder to gain without changing the exercise up. Same thing is true with fins. Now the SD-1 Military is not all that different than the Jet, but it is more flexible and due to the ergonomic foot support its doesn't have the tactic feedback, but it still requires an adjustment period.

as far as surface swimming, people always whine about how hard snorkeling with Force Fins is, but I just never experience this problem, its just a matter of technique. For years I was doing dives that had 1/2 mile or further surface swims to get to and it was never an issue.

edit- after thinking on it for a while last night I came up with a method that should convince most that the SD-1 outperforms the Jet. Use them for 5-10 dives in easy to moderate conditions to get accustomed to the fins. Then take them out looking for challenges. All I can say is, good luck finding challenging conditions. Once you know the fins, the conditions will be absolute hell before they fail to get you where you want to. And yes I realize that I saying a fin can fail, which is an absolute absurdity, your legs may fail, but fins can't (unless they break of course, although that's rare). The point being, the improvements in the foot support and flex profiles not only provide at least as much propulsion, but harnesses the muscles in such a way that you will fatigue much slower and maintain the high level thrust for much longer getting where you need to with less effort.

 

[deco_martini]

Or maybe the lead weight in pool test.

Someone posted a couple videos in one of the splits vs paddles thread debunking myths. One of the video comparisons was done in a pool.

A free diver dove to the bottom of the pool and first tried to pull 30 or more pounds of lead weight attached to a belt up using jets. He then repeated the same test with twin jets. He actually appeared to have an easier time of it using the twin jets.

In that situation, you need startup thrust and you need it quickly. No matter how the person who is performing the dive feels mentally or the lack of feedback they feel from the fins, you have the video showing how they actually perform.

 

[deco_martini]

Fin_Thrust video by diverdave - Photobucket

Here is the video that was posted in the other thread. Seems easy to replicate.

 

[Bob Evans]

Deco, sure glad I stopped using Jet fins and with a split down the center, hurt watching the video. Like to see the same game, but without the heel strap on, wonder what would drop first, the fin or the weight ?

 

[Underwater Ogre]

As a river guide, I have used heaps of fins going against the current in a river. This seems to be the best way to put them to the test. Kind of a wind (water) tunnel.

U/O

 

[deco_martini]

Well, the weight test would be a way to test the startup power of the fin is all.

DA was worried that moving large amounts of weigh quickly and precisely in a cave environment might be more difficult.

A river test might be a different problem to solve.

 

[Blair Mott]

A lot of great posts in this thread. Thank you everyone for your energy and input. Bob and I were talking yesterday about all the info in this thread and there is one basic difference that everyone must face- Jet Fins are a true Terrestris Fin. In a current you kick a paddle fin harder because you can not kick it smarter!
We are very thankful for all of your feedback we are looking forward to more!

 

[laurin]

A lot of great posts in this thread. Thank you everyone for your energy and input. Bob and I were talking yesterday about all the info in this thread and there is one basic difference that everyone must face- Jet Fins are a true Terrestris Fin. In a current you kick a paddle fin harder because you can not kick it smarter!
We are very thankful for all of your feedback we are looking forward to more!

Being a Jet Fin user from dive #1, this thread caught my attention.

I've always regarded FFs as a diving equivalent to snake oil, and DA's review at least revealed that they might not be that bad after all.

BUT. If you really want convince the crowd that really care about their propulsion, you're not going to do that with snappy slogans and funny pictures. Just get hold of somebody who really knows their frog, mod frog, helicopter turn and backward kick and shoot some video with them. I've mostly seen Force Fin videos of people with bad trim doing scissors kicks at a pace completely irrelevant to scuba diving. Unless you're into short distance swimming competitions, that is. The only video I've seen showing frog kicks with FFs wasn't really convincing, the diver either wasn't that hot with advanced propulsion techniques to begin with or the fins were to blame. Given DAs evaluation I'd assume the fins weren't entirely at fault there.

This is a bit confrontational, but the material behind those links was just somehow really annoying. Like the whole point of diving was to kick like crazy with no regard to environment or other divers. I'm just completely missing the value proposition of FFs, especially considering the price.



//LN

 

[TSandM]

I spend a lot more time underwater maneuvering myself precisely, than I do trying to generate tons of force -- the only place I've had to do that was in high-flow caves in Florida. To maneuver precisely in my Jets, I use my ankles and the muscles in my feet. I wonder how well this works with the foot pocket in the Force Fins -- DA, can you comment on that? We've kind of gotten focused on sheer power here, but there's a lot more to finning than that, even in caves.