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.
Excellence is always to be celebrated! FYI - I've a training coming up in August - be good to have a Pilot on hand - it's mostly apt to be scubies!
