I've been away for some time from this thread and despite the arguments in my previous post not having been addressed (maybe the currents were not favorable even to those with freediving fins...), I have a few comments to several posts.
My point was that it is foolish for people like Bob, or shops, or the industry, to allow new divers to think that ANY fin they like, will be good for them in emergency situations.....
I agree. There is clearly bad gear out there and many times instructors / dive shops don't care much or even try to sell what's more convenient for them. But there are bad professionals everywhere.
What I don't know is if it's fair to include "split fins" in the "bad gear" category because it will depend on the fin. Fin comparison tests have shown some models of spilt fins to be faster than regular fins. Although some others were crap.
I personally don't like split fins for several reasons and probably wouldn't recomend them, but there can be exceptions like bowlofpetunias has pointed out. Many divers have limits in their diving. If one needs to use split fins, then it can adequate the dives to that fact.
I don't have any idea of how they behave with sideways current, it may well be they don't perform as well. But you are mentioning many times your experience and failing to recognize the reports from divers who have splits and are fine in currents:
Confession time: Hello, my name is Amanda, and I wear spilt fins!
5 years diving all the dive sites in Bali, including the more extreme sites on a regular basis, had very strong down and up currents, and I wear split fins. Never had any problems with them, can kick as strongly as the next man, and find that solid fins give me cramp.
The argument that splits don't work in current is rubbish in my experience. I did a dive where we got into ripping current. It was bad enough that the mooring broke. That meant we had to do a swim against the current to get back to the boat. Only 4 divers made it back to the boat against that current and I know for a fact that 3 of us were wearing split fins(not sure of #4)! The other 6 divers wound up surfacing a long ways from the boat, and linked arms with their SMB inflated to wait for the boat to get them. NON of them were wearing splits but they couldn't get back to the boat against the current
Clearly you know nothing about free diving fins......you keep babbling about the power it takes to use them...And yet, one of the coolest things about freedive fins, is that they have soft models for weaker muscled divers
Sometimes I wonder if you really know how fins work. Free diving fins of the same stifness of a smaller typical scuba fin, being larger will have a larger area in contact with the water and thus offer more resistence to the kicking action. Since each action has an opposing reaction, that reaction is what propels the diver forward. Since this is also greater, the diver moves faster. IF he can kick with the same velocity. And maybe even being slightly slower will still result in greater speed. But if the diver is not fit enough for this, then it will kick slowly, or get tired, get cramps... As you say, there are softer blades. A softer blade will bend more, and the forward propulsion will be more due to the blade springing back into its flat shape. This is all very good in a streamlined free diver or when there is little current. In stronger current they will not be as efficient as the hard blades and will not be enough. So we go back to requiring fit divers. (Not that I think a diver should be out of shape, but there are many divers physically well who wouldn't be able to fin hard with freediving fins).
This statement confuses me. Say I am in a horizontal position and I am kicking straight ahead in the direction my body is pointing. I can see how fin type can affect my velocity. But I do understand this destroy business. So I am drifting at the speed of the current. As far as my fins and body are concerned there is no current. I am motionless in the water. There are two vectors relative to the ground. The velocity vector of the current and the velocity vector generated by my kicking. I would think that basic physics would say that I move in the direction of the sum of the two vectors. So say I am oriented perpendicular to the current and my kicking velocity is 5 ft/min. If I kick for x min I am going to move 5x ft perpendicular to the current. The effect of the current is to move me down current. So if the current is 50 ft/min after x min I am 50x downcurrent and 5x cross current. I do not see where the side movement is affected at all. My amount of side movement is independent of the current velocity (ignoring any turbulence).
Since danvolker went on with confusing vectors and split fins and whatever more but didn't explain you what you had asked...
You are right in your assessment.
But if you are swimming towards a fixed point, with the current perpendicular to your swmming direction, then if you have faster fins / kicking, you take less time to cover the distance to that fixed point. Let's imagine that point is an island, as it could have been in this accident. If you were faster covering that distance, then you were also taken less downcurrent and that may allow you to hit shore. If you think that since you are not fighting the current you can have less powerful fins / kicking then it will take longer to cover the distance to the island and you'll be taken further downcurrent meaning you can actually go past the island and miss it.
Steve, Thanks for raising this question!!! I would have hoped Bob would have.....
That was a clear and unjustified personal attack... See why people don't like your attitude?
Hi Tom,
I don't push freediving fins for wreck penetrations...Myself, I have enjoyed both wrecks and reefs for a very long time....and have found that MOST wreck penetrations that I do, are better handled with freediving fins......
Really, now freediving finns are the best for wreck penetration?! I wonder why none of the wreck instructors and teaching organizations have discovered that!
I've done it with long fins and did not enjoy the experience. Maybe you should try some shorter ones.
I don't understand why longblades would be more dangerous. Does this mean being 6'8" and diving wrecks is more dangerous than being 5'4"?
You can easily do a modified butterfly type kick with long fins that directs the water upwards and not down into the silt. I don't silt up outside a wreck with them....so why would I silt INSIDE a wreck? (I don't do deep penetration wreck diving so pardon my ignorance here)
A tall diver can still bend at certain places, although yes, I'd say that large divers may have more difficulties in certain wrecks and caves.
But regarding fins, modified butterfly kick? Like dolphin kick? Not usually the best... and in a way simillar to the modified flutter kick. In some situations it's not the best and it does push water towards the bottom and, being larger fins, more water is pushed.
If using frog kick, with a lot less amplitude of the legs, the fins will more easily start hitting the sides. Also harder when going around corners. Also more cumbersome when going through vertical openings...
Freedivers move reasonably quickly through the water because they are very streamlined.
Generally a freediver's goal is to move efficiently rather than "fast". Rarely will a freediver kick their fins "hard" or try to swim at a speed that is anywhere near their maximum (while in open water).
Quite true, being streamlined makes a huge difference, especially when dealing with softer fins. And their efficiency comes from the slow movement with wide amplitude. Maybe softer fins would work, but with a considerably faster kicking.
It's similar to an erg (rowing) machine. We can row as fast (the velocity of the theoretical boat) by having a high drag and dowing slow, strong movements or we can have a low drag and have to do much faster movements.
And faster movements can be done also by those with smaller fins. Besides, it all depends on the particular person, some people are better for speed, others for strength. There won't be an optimal "one type of fin is best and fits all divers".
Again Bob, you keep forgetting what this forum is for...it is for preventing accidents in the future, by looking at past accidents.
That requires us to know how the accident happened and not assume things like a) they had split fins b) freediving fins would have made a difference
They could in some situations? I agree, I have powerful fins and I wouldn't trade them. But you can't say that
COULD be the difference between life and death, in a place where 5 minutes of fast swimming, could prevent you from being swept out to sea....
You started this discussion focusing a very particular incident and saying that free diving fins would have saved them.
And from some of the other posters, indicating that in this part of the world, there are many divers that can't even swim ( another indication the non-swimmers probably use split fins--as these require no skills to propel yourself with)
See here why your "split fins are bad" reasoning may be wrong? Because it may be the diver, not the fin.
In my opinion people should be able to swim and maybe freedive minimaly to do scuba.
This is not really about what these divers did right or wrong...it is about what happens if you are in a place with extreme conditions going on, and there is no boat....
- How will you use the gear you have to attain the objective....If there is a short area that could be crossed quickly, that could give you massive assistance in gaining safety-but crossing quickly means getting to the bottom and going hand over hand with the air left among your group...this is a theoretical strategy and problem solving issue divers need to deal with....or, if they all just go to maximum crusing pace at 10 feet below the surface, with the remaining air they have left, and follow a compass heading
This started exactly because of those divers and what in your opinion they did wrong.
In general, discussing equipment and the prons and cons of having someting is always of value. Not so much when you see no cons on a specific item...
And in this case, as well as probably the majority of cases, after a dive has ended (usually when divers reached their reserve and are closer to the NDL, going back down and do effort doesn't seem like a good solution.
I don't see how discussion of gear and strategies for future trips--in adventure areas like this....is not something that everyone would see value in!!!?????
It is and people have discussed several things, the use of SMBs, PLBs, life rafts, boat procedures, the weather evaluation, etc. You focused on fins with no indication whatsoever that they would have changed in any way the outcome.
Here is my personal experience for whatever it is worth. I have dived paddles, splits but not freedive fins. I know what works for me. I changed to splits because of knee problems and have since developed a problem with one foot and ankle. Splits mean I can keep diving! 
I suspect a couple of them could have made it but chose to stay with the group they were with. Not a bad decision. In the incident in Indonesia I suspect that staying together contributed to the survival of the divers.
