Got my Jet Fins!

[tomcat]

my observation has been that jetfin owners tend to smack down on split fins. i have dived the jetfins, own a pair of rapidas (really stiff plastic thingys from mares), owned the xpert zooms and currently use the biofins.

fins are a matter of preference. while i tend to agree that splitfins do not belong in "tech" environments, not everyone would find jetfins to be the most appropriate in openwater environments either.

1. they hurt like hell at first (got blisters on feet)
2. need really strong legs (recipe for cramps if you're 90 lb weakling like me)
3. more power = more effort = more air (race a split over 300 ft and see who lasts longer)

i'm guessing that just as i may not fully understand how best to use jetfins, jetfins users, who are accustomed to big powerful kicks may not fully understand how best to use splits.

now that i'm using the bios most of the time, i have had to reduce my kicks to ankle or even toe kicks, or i leave the rest of the group behind. yes, maybe they are just taking their time, and yes, not many of them were wearing jetfins...but the ooint is, if in a real life scenario you can use mimimal kicks and still travel at the same speed as the group you're with, the fins must work!

as for "techie" kicks with splits, with the exception of reverse finning, everything else is just as feasible. obviously the effectiveness of the kicks will depend on the skill of the diver and the familiarity with the fins. i'm sure you've seen divers who can't do the kicks properly with jetfins either but that doesn't mean that jetfins are no good for those kicks right?

(ok, you can flame me now! )

 

[metridium]

tomcat wrote...

1. they hurt like hell at first (got blisters on feet)

What sort of booties were you wearing?

tomcat wrote...
2. need really strong legs

Thanks for the compliment!

 

[tomcat]

3/4 cut mares neooprene booties (about 2mm i think). i must have really soft and tender feet as well

 

[metridium]

This is probably going to come across wrong, but are you sure they were the right size?

 

[tomcat]

well...it is hard to say. i'm a consultant by day so we like to make simple things complicated so that there is more to talk about.

1. how do you define what is "the right size"?
2. since fins only come in only that many size gradations, there can never be a perfect fit anyway
3. if i wiggle my legs and they don't flap around much, is that considered the right size?
4. my other fins are about the same size and they don't give me blisters, can that be used as a gauge?
5. is it possible that jetfins were not designed with comfort in mind such that if they do feel comfortable, it is through chance rather than by intent?

 

[DiverBuoy]

I've dove 5 different ScubaPro Twin Jets for at least 1 dive. Rather than give strictly my opinion - I'll share what the mfg says and what I've heard from other divers who can't live without them:

1. Black - made from the same material as water drums used for the military. These are denser and negatively buoyant. They are stiffer and ScubaPro claims they put out 2-3 units of energy for every 1 unit applied. Divers who have dove them for years claim they become rubbery over time - and like a fine wine only improve. (I'm sure they made these claims in around 150 feet of water).

2. Grey - I dive these currently. Here ScubaPro claims these graphite put out 5-6 units of energy for every 1 unit applied. They are positively buoyant. Most divers claim they completely forget they have fins on.

3. Blue - same characteristics as Grey, different color.

4. Yellow - softer than Grey and Blue. Ultra comfortable, but I've heard complaints they don't help much in a medium or heavier current.

5. Clear - these were prototype full foot fins - very limited number. About the same characteristics as Yellow. I've sent to the mfg recommending they sell these, I believe they would be popular among instructors for pool work and for warm water divers.

 

[jonnythan]

DiverBuoy once bubbled...
I've dove 5 different ScubaPro Twin Jets for at least 1 dive. Rather than give strictly my opinion - I'll share what the mfg says and what I've heard from other divers who can't live without them:

1. Black - made from the same material as water drums used for the military. These are denser and negatively buoyant. They are stiffer and ScubaPro claims they put out 2-3 units of energy for every 1 unit applied. Divers who have dove them for years claim they become rubbery over time - and like a fine wine only improve. (I'm sure they made these claims in around 150 feet of water).

2. Grey - I dive these currently. Here ScubaPro claims these graphite put out 5-6 units of energy for every 1 unit applied. They are positively buoyant. Most divers claim they completely forget they have fins on.

3. Blue - same characteristics as Grey, different color.

4. Yellow - softer than Grey and Blue. Ultra comfortable, but I've heard complaints they don't help much in a medium or heavier current.

5. Clear - these were prototype full foot fins - very limited number. About the same characteristics as Yellow. I've sent to the mfg recommending they sell these, I believe they would be popular among instructors for pool work and for warm water divers.

Where does this info come from? "5-6 units of energy for every 1 unit applied" doesn't even make sense. Where does Scubapro claim this?

 

[DiverBuoy]

I explained where the info came from - ScubaPro (their reps actually) and the opinions of divers who love twin jets.

The mathematics you refer to are called ratios and allow for independence in unit of measure. They make perfect sense.

 

[jonnythan]

DiverBuoy once bubbled...
I explained where the info came from - ScubaPro (their reps actually) and the opinions of divers who love twin jets.

The mathematics you refer to are called ratios and allow for independence in unit of measure. They make perfect sense.

First of all, I don't think something some rep may have made up and told you counts as an official Scubapro claim. I'd *LOVE* to read some official Scubapro paper that claims this.

Second, it *doesn't* make any sense. You can't get more energy out of a mechanical system than you put ino it. The best you could hope for is a decent efficiency, and I'll bet you're lucky if you turn 1/3 of the work you put into a kick turned into forward motion.

I feel sorta bad about jumping on this, but you've been posting a lot of drivel and misinformation to this board. What's up with that?

 

[DiverBuoy]

please give some examples.