Extreme Dolfinism G2

Well, what a nice surprise after getting home from a trip, the review is up and it is fabulous. Thanks Fondue!!. Having three different perspectives adds hugely to its usefulness.

I did not realize Fondue was going to include my comments to him in his review. There is more to be said, and I'd love to see some comments from other divers.

Ron , would you prefer to keep the review comments in this thread or should I start a new one on just the review? It would be a lot easier to find if it had its own thread.

Connor

cdavis said:

Well, what a nice surprise after getting home from a trip, the review is up and it is fabulous. Thanks Fondue!!. Having three different perspectives adds hugely to its usefulness.

I did not realize Fondue was going to include my comments to him in his review. There is more to be said, and I'd love to see some comments from other divers.

Ron , would you prefer to keep the review comments in this thread or should I start a new one on just the review? It would be a lot easier to find if it had it own thread.

Connor

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HI Connor, OOPS! Should've told you I was going to use your contribution verbatim. You and Eric are both so well spoken and concise that I didn't see the need for much editing.

Useful is exactly what I was going for. I took what I expect from a review, then toned it down just a little so everyone wouldn't nod off...

Comments in under part 1.

opps, something not right with the comment section on the review. I posted, but it did not take. Monitors move the post below if that makes sense.

There are several things that I did not mention in the review that are worthy of comment.


The surface diving ability of my Dol-fin is outstanding. This probably extends to the Orca, I just haven't tried it (yet!) My diving dates back to that prehistoric period before longfins. We used Jetfins, short, stiff and heavy as heck, which surface dived very well. For all their advantages, switching to longfins was a pain from the surface dive point of view. The diver has to balance a very long floppy lever up in the air before he finally sinks. Its also harder to get that long draggy fin quickly up in the air to maximize the effect of the surface dive. This takes attention and energy that could be much better used in the dive. Most divers have known nothing else and so do not recognize that things could be better. Things are much better with a Dol-fin. It is stiff, small, relatively short and fairly heavy in the air, just like Jetfins. Accordingly, the surface dive is easier and much much more stable. Once the fin is in the water, it has much less drag than other fins, bi or mono, so the diver maintains speed for longer and gets deeper with the less effort. All for the good.


Customizing is where the Dol-fin really gets interesting. We are just beginning to explore the customizing ability of the Dol-fin series; there will be lots more of this. I've been working on adding buoyancy to my fin for a while(getting it right is amazingly difficult), primarily to make it easier in a vertical descent. Eric is ahead of me, as usual, in figuring out different buoyancy amounts for different activities. I'm pretty sure that buoyancy is going to be a very personal thing, dependent on both the diver, the gear he is wearing, and the activity, but developing some general rules will be super helpful for most divers. .


One area where the Dol-fin is radically different from other fins is drag. It has far less than anything else out there, because the blade is both so small and so thin. This has a multitude of impacts, some have been commented on, like long glides, different level of feedback, feeling of effortless kicking, etc. There will be others we have not thought much about, some are probably unknown at present. Impact on descent is one of the ones we know about. The fin is so slick that it wants to fall faster than the rest of you and you may find yourself falling sideways unless you keep kicking just a bit, not something I like to do. Thick wetsuits on the legs minimize the issue. A neck weight helps(its critical when using a Dol-fin) but the issue is still there. Eric and I have added buoyancy to the fin to counter that tendency. My technique isn't all that good and I'm wearing minimal wetsuit, so, (I think), the issue gives me more trouble and I am now experimenting with a whole lot of incompressible buoyancy, balanced by adding a bit of weight to my belt and/or neck weight. Still experimenting.


Another area that bifiners will notice is the tendency for the fin to sink and fall out from under the diver when he/she is sitting still on the surface. The unmodified fin is negative and even after adding considerable buoyancy, mine still falls because my legs are negative. Bifins are also negative, but its easy to counter with a minimal scull that the Dol-fin can't do. This won't affect all divers, since many are wearing considerable wetsuit on their legs, but I dive in tropical waters with little or not suit on my legs. I'm experimenting with a wrap of wetsuit material around my ankles. This is going to work, but I haven't got the details straight yet.


An area where I may get some disagreement is undulation. IMHO, if you don't want to go fast and your undulation technique is poor (and/or your back is as stiff as mine), it will be more efficient to use your ankles plus just a bit of pelvis to drive the fin. Your knees can be nearly straight, stroke amplitude is small so the whole system stays very streamlined and the energy expenditure is small. That will get you something more than 1 m/s, plenty fast enough for most open water diving activity. .



All in all, a fin that truly engages your brain. It works great straight out of the box, but the possibilities for technique improvement and customization are nearly endless and will keep you thinking for a long time to come.

Gads, is that a luno along with the Orca?? I did not see a luno in the video that was the same session as the pic.

I don't think it's a luno.

Those PFI'ers are using some weird, non-articulating "dolphin tail" mono for the kids.

It's got traditional styles footpockets and LOOKS like dolphin flukes.


Sent from my iPhone using Tapatalk

link took me to Walter Johnson's page, but I did not see anything about the foil.

REVAN said:

I thought that might be the case. Apparently, unless you are a Facebook "friend" of Walter's, the link is no good.

Walter's comment:

"Moving to the ORCA 2 wing suspension system. We did destructive testing on my old wing (because we could), and believe me, you will never bend one of these wings by accident. It just takes too much force."

Specifically, it supported my weight applied near the half-span of the foil with a good bit of deflection, but it sprung back. In terms of water load, it should be able to carry a load of about twice my weight if used as a hydrofoil of similar span but attached to a boat instead of a monofin.

It was not until Walter locked his knee in the center of the fin and pulled on the ends of the 32 inch long foil as hard as he could that he was able to actually damage the part. Of course it bent where the notch for the Orca1's fin suspension system was cut out. That notch removes around 20% of the cross-section. This is eliminated in current designs, so the Orca2 fin is even stronger than what we tested.

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Ron's work on coming up with an easier to manufacture fin, the Pilot, has produced another really solid design in every sense of the word. Obviously by choice of materials but more so by simplicity of design. I am a clumsy Ox and in the five months I've been using the Pilot2 I've thwacked pool sides, bottoms and steps without any damage beyond the odd scuff here and there, but then you'd expect that.

The foil's articulation joint, the suspension strap, is simplicity itself so I cannot imagine that deteriorating any time soon and the fin tips, that nicely fold down for transport, have taken quite a bit of punishment too - care of my afore mentioned clumsiness.

I love my DOL-Fin Pilot, hard as nails and flies like a dream when you're in the grove. Just what you want from a monofin.

Reassuring. Looks like mine is safe from "almost" anything. I'd already concluded that it was tough enough I did not need to be worry. I still have a bit of concern about leaving the foil resting on two points at the ends of the foil with no support in the middle, then having someone fall on the center, more force than even Walters knee. That kind of crazyness can happen in a rolling boat, but, if that did not bend it, it would be the only thing on my boat to survive such treatment.

Great reviews, guys. Just wanted to add that I've had one of the original X-20s and it's as good as new. Been using it for three years. Great to see the designs evolving and building on that excellent foundation.

Pete

laminar said:

Great reviews, guys. Just wanted to add that I've had one of the original X-20s and it's as good as new. Been using it for three years. Great to see the designs evolving and building on that excellent foundation.

Pete

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If I'm not mistaken - you are the original beta tester! I thought to get your input - the review was already blossoming into a short novel.

Laminar, I think my fin is the same one you beta tested.

cdavis said:

Laminar, I think my fin is the same one you beta tested.

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No, not quite! Mine has "x-20 experimental" written on it. Ron can have the final say on whether they are the same model. But 20 is better than 18 is it not?