Short vs long fin? (Efficiency)

[eb3ha4el]

Heres test by professional

Leaderfins 60-70-80 cm performance

Leaderfins is one of the most important international designers and manufacturers of freediving and spearfishing fins, but also fins for underwater games

apneapassion.com

My personal dynamic comparison with carbon long(60cm) vs short (40cm) is that longer one has about 15% more efficiency which translates to 15% more distance can be covered by same breath.

What is your opinion?

 

[Mr. X]

I bought some shorter spearo fins in a closing down sale after finding I'd left by usual long fins at home while packing our car for holiday!

The short fins worked fine , but they were definitely not as good as my regular long fins. From this experience , for me, long fins are significantly better: you can go further, faster, and with greater confidence. But both worked fine.

Note: I may be biased, as I am much more familiar with my long fins and the shorter fins' foot pockets were also a bit big for me.

 

[cdavis]

A subject with a lot of different answers,

I've used longfins for a lot of years, much more efficient than scuba or short fins. I once was having knee problems and a friend lent me a pair of semishort plastic freediving fins. They were about 6inches shorter than my usual plastic longfins. I found them to be pretty close in performance. The shorter fins required a faster flutter kick but after that adjustment, seemed to work as well. Also kept the torque on my knees to handleable levels. I used a fiberglass fin designed for spearfishing for many years. It was a couple of inches shorter and almost an inch wider than most longfins. For spearing I found them much superior, more manuverable and better acceleration, both key characteristics for my kind of spearing. Hard to compare efficiency, but I think the spearing fins were slightly less efficient than more normal freediving longfins, maybe.

 

[Scott Valentine]

I used regular long fins for a number of years and then switched to the short version of the long fins, I think they're about 4 in shorter, and I don't really see any noticeable difference
I switched simply because they fit in my travel bags easier and I don't have to disassemble them to fit them in the bag which is a big plus when hopping frequently between islands like I do

 

[Mr. X]

I bought some shorter spearo fins in a closing down sale after finding I'd left by usual long fins at home while packing our car for holiday!

The short fins worked fine , but they were definitely not as good as my regular long fins. From this experience , for me, long fins are significantly better: you can go further, faster, and with greater confidence. But both worked fine.

Note: I may be biased, as I am much more familiar with my long fins and the shorter fins' foot pockets were also a bit big for me.

Interesting. My "long fins" are quite wide too - Beachat Competitions.

I have 2 pairs of them now, one pair unused spares. Having once broken one of their very tough blades in extremis, and so I was stopped from further diving until I could order a replacement blade and fix- kit from France. [Actually I ended up buying 2 new brown blades , which I now use, and keep my other old blue one that I camo'd with artists oil paints as a spare . I also bought another complete new pair of the same Beachat Competition fins, albeit with black blades, as spares - as yet unused. So as not to be blocked from diving by fin problems again. Unfortunately it did not save me from failing to pack my fins in the car when preparing for my holiday a few years ago . ].

 

[eb3ha4el]

I used regular long fins for a number of years and then switched to the short version of the long fins, I think they're about 4 in shorter, and I don't really see any noticeable difference
I switched simply because they fit in my travel bags easier and I don't have to disassemble them to fit them in the bag which is a big plus when hopping frequently between islands like I do

Thanks for sharing

Though if 4in shorter i would say that is sort of middle fin. The short fin i like to buy is about 8in shorter than standard long. That is, including foot pocket they are about 65cm in total length

 

[eb3ha4el]

I bought some shorter spearo fins in a closing down sale after finding I'd left by usual long fins at home while packing our car for holiday!

The short fins worked fine , but they were definitely not as good as my regular long fins. From this experience , for me, long fins are significantly better: you can go further, faster, and with greater confidence. But both worked fine.

Note: I may be biased, as I am much more familiar with my long fins and the shorter fins' foot pockets were also a bit big for me.

Thanks for opinion. I do believe the same.

 

[eb3ha4el]

A subject with a lot of different answers,

I've used longfins for a lot of years, much more efficient than scuba or short fins. I once was having knee problems and a friend lent me a pair of semishort plastic freediving fins. They were about 6inches shorter than my usual plastic longfins. I found them to be pretty close in performance. The shorter fins required a faster flutter kick but after that adjustment, seemed to work as well. Also kept the torque on my knees to handleable levels. I used a fiberglass fin designed for spearfishing for many years. It was a couple of inches shorter and almost an inch wider than most longfins. For spearing I found them much superior, more manuverable and better acceleration, both key characteristics for my kind of spearing. Hard to compare efficiency, but I think the spearing fins were slightly less efficient than more normal freediving longfins, maybe.

I dont have any interests in spearfishing so i never looked at it but since you say more manuverability, im hooked in.

So in terms of blade, what is diffetent from freediving one? Provided that the length and material is the same. More stiff?

 

[adrian.u]

I think it's an interesting experiment, though there are several potential issues/questions that come to mind...

1. Was this recording only a single dive for each length of fins?
   - The text references "multiple and consecutive dives", but I get the feeling from the rest of it, and from the profiles, that it may only be one dive per set of fins...?
   - Either way, I'd be interested to see how much variation there would be (/was) between dives (compared with variation between fins).
2. Following on from that, a less experienced diver may well be less consistent across dives, so how might this inconsistency affect results?
   - Could such variation be larger than the variation caused by different lengths of fins?
3. Again, following on from that, how much does previous training and technique play into this equation?
   - Does the diver involved (Luciano Morelli) normally use longer fins (probably!) with that same stiffness?
   - Could the results be somewhat different for others who are more used to different fins? (both length & stiffness)
4. How much would personal physical characteristics play into this, also along with fin stiffness?
   - Could the results be affected to some degree by different body shape/mass/muscles, etc?
   - Might it even be the case that certain body 'types' fare better (in certain ways) with a particular length for a specific fin stiffness?

Anyway, those were my thoughts, so I guess I'd say that the bottom line from the above experiment would be that it seems highly plausible that longer fins can give some speed/acceleration advantage for Luciano Morelli in particular (though stats for repeated dives would help strengthen that conclusion).
Also, intuition about how fins work does suggest it's plausible that the conclusion could extend to other divers with similar level of experience/training/background.
However, I suspect it's harder to be so sure that the results would carry over so cleanly for different body types, and whether it'd be so clear-cut for us mere mortals who only get to dive (to depth) a few times per year( )and who therefore likely have considerable inconsistency in technique/etc...

In conclusion, if this experiment was repeated with numerous volunteers (hey, look - I have my hand up! ), with differing body characteristics, different levels of experience/training, and across multiple dives (all of which which takes time, of course...), then it'd give much more helpful info.


Personally, I went for slightly shorter fins, specifically for reasons already mentioned above (when disassembled, I can fit them into a hard suitcase for travel). Also, I practise with them fairly regularly in my local pool (which is fortunately not heavily used), and longer fins could more easily get in the way of other swimmers (though I don't use them if there are more than a handful of others in the pool).

 

[cdavis]

The blade was made by Specialfins, fit sporosub pocket among others. Called Kelpies. They list the same name in their production, but its not the same design, more a traditional fin. Mine were medium stiff fiberglass and were about right for my legs when I bought them. Since then, I've gottten old, don't have the leg strength anymore, and have gone to soft fiberglass fins in a more traditional design.

Adrian is right about the diffuculty in comparing fin performance. I spent a lot of time and effort trying to compare things like efficiency and speed and finally gave up trying to get a reliable answer. Its just too complicated.