Fin buyers remorse, back to the drawing board? what should I do?

[flots am]

To me the idea is kick and glide. It seems to me that 1 kick requiring a little more force is more efficient than 2 or 3 easy kicks.

Unfortunately, there's still no free lunch.

The only thing that matters is how well the fin directs the water in the opposite direction from your intended direction of travel. It doesn't really matter if it's one hard kick or two easy kicks. Energy is energy and efficiency is efficiency.

What does matter is how much water (energy) is directed in useless directions like up, down and sideways, since this doesn't contribute to moving you were you want to go, but does use energy (and also stirs up silt if you're near any)

flots.

 

[bamafan]

TE=flots am;7114519]Unfortunately, there's still no free lunch.

The only thing that matters is how well the fin directs the water in the opposite direction from your intended direction of travel. It doesn't really matter if it's one hard kick or two easy kicks. Energy is energy and efficiency is efficiency.

What does matter is how much water (energy) is directed in useless directions like up, down and sideways, since this doesn't contribute to moving you were you want to go, but does use energy (and also stirs up silt if you're near any)

flots.[/QUOTE]


I agree that what we are doing is trying to not waste energy. I would say that freediving fins are the epitome of this. Their fins are long and stiff. Now we don't use longblade fins in tech diving but we do use a wide stiff fin. I try not to waste any motion underwater and with the legs being the largest muscle group in the body it would seem to me the less you move them the less air you will use. This reasoning has worked for me so far. Maybe there is some small super efficient fin out there but I haven't seen it yet. I would gladly try them out if it is. In the meantime I will stick with my lipstreams. They are getting pretty beat up and I have been meaning to try a pair of the Dive Rite Exp's. but I never think about it when I am around a set to use. The opportunity was asking for opinions and you know what those are like. I've yet to see a cave diver with decent air consumption
diving some tiny floppy fin. Maybe they are out there but I would have to see it to believe it.

 

[mddolson]

How about a pair of lightning (lighter) jet fins? (Lighter than original jet fin)
Add spring straps & Bob's your uncle.

 

[Progen]

For me, now that my rig's the way I like it (barring a few very minor non-essential modifications which can wait), I'm more concerned about weight distribution. I'm using Jetfins which were the solution for me in the beginning when I had floaty feet but now, I find that I'm feet heavy so although my trim's fine, it can be even better were I to be perfectly balanced in the water. Have confirmed many times that I am feet heavy many times by either pausing in the water, stretching my hands out in front and holding my U.K. Light Cannon (a fairly heavy light), rocks or bits of dead corals to see where I needed weight to achieve that perfectly motionless AND effortless horizontal hover.

 

[flots am]

I had floaty feet but now, I find that I'm feet heavy so although my trim's fine, it can be even better were I to be perfectly balanced in the water.

Very few people actually have "heavy feet".

It's much more likely that you're overweighted and have air in your BC, giving you "floaty head", or possibly just incorrect trim weight distribution.

 

[Progen]

I had some videos of myself in a swimming pool where there's no current and it was pretty apparent that everytime I stopped finning, my butt would rise so switching to a heavier pair of fins (from Mares X-Streams to Jetfins) helped immediately and I stuck to the Jetfins because I liked how they were nice and simple and what you put in was what you got. As for overweighting, that's quite impossible because I didn't carry any and in freshwater, I'm quite negative from start to end. Also couldn't shift the tank down much because the tank strap was quite close to where the tank tapered off to the neck.

 

[eelnoraa]

Very few people actually have "heavy feet".

It's much more likely that you're overweighted and have air in your BC, giving you "floaty head", or possibly just incorrect trim weight distribution.

I won't say that. Quite a fewpeople I dive with, including myself, are leg heavy including myself in wetsuit all the way up to 7mm. Even with OMS slip, I need to put 6-8lb on my top camband with AL plate. In drysuit, it is easy to handle by letting a bit of air into feet.

 

[bada3003]

When I took a cavern course I took my SMS 50, Aeris Accel fins (they're shaped more like old school fins but are compact and light), 7mm wet suit, etc. as carry on. In high flow FL spring water, however, the accel fins seemed to lack power. My instructor suggested trying out jet fins.

After the ice melted locally, I've been diving SMS 100 with jet fins, dry suit, rock boots, and a similar trim issue as the OP's arose. I have two SP jet fins, size large (of similar length as the accel but much heavier) but my SP rock books (size ML) don't fit (at all). Yea, SP sizing is a bit erratic at best. I got the XL, which barely fits (the hardest part of entering/exiting water), but once in water frog kick etc. work fine. Put weight pockets in the shoulder harness, 3 lbs each, trims out nicely with two Worthington LP85s. With a couple of AL80s, I strap 3 lbs to the cylinder cam straps and they roughly approximate the buoyancy characteristics of the Worthingtons.

The XL jet fins are much larger and heavier than the size L jet fins, and keeping the feet up took some effort initially. After 30 min bottom, some cramping in the legs even (but could also be due to 40s degree water temp which shunts O2 away from the limbs). Anyhow, now I'm used to it, trim is good, propulsion powerful. More strain on leg muscles? No doubt. But performance wise I think overall worth it. So, yes, putting some weight on your shoulders will likely work. With the regular SM 50 (not Sport) which has the neck weight pouch, putting some lead there might work as well.

I did order size M SP rock boots (XLs are too tight but the XXL fins are way too large) to see if they'll fit my feet with neoprene sock dry suit (SP evertec). If they don't, I may have to go shopping with my rock boot in tow, hoping to find a tech fin that actually fits it.

 

[boulderjohn]

I first tried the SMS 50 in Florida when I took side mount classes. The instructor immediately looked at my Hollis F1 fins and suggested that I would be happier with something lighter. I stuck with the F1s, but I did not like the SMS 50 and felt it did not have enough options for trimming out. I was able to overcome that and get myself in trim, but the instructor had an SMS 75 prototype I could use, and I immediately felt the difference and liked it. I did the class (and more) wearing it. Another student had the SMS 50 and heavy fins, and he was struggling with trim as well. Our instructor played with the design of the rig itself, making changes that really helped. I am having trouble visualizing it from memory because I no longer have an SMS 50 around, but I recall him playing with the waist strap design because as it was set up, it tended to put pressure on the bottom part of the bladder, forcing the air up toward the shoulder. I remember the instructor working with that student's trim, looking at me, calling me over, and showing me how the belt design was doing that.

I do agree with Bob, that with experience you can overcome it--I think the other student could have overcome that problem a lot with a little more skill work. He was not nearly as experienced as I.

I am still waiting for the SMS 75 I ordered to come in. If you are going to dive Florida, I suggest going with the SMS 75 or 100 instead of the 50.

 

[bada3003]

Interesting. Not an expert in sidemount so can't comment on the waist strap bladder issue. I dove the SMS 50 (Sport) with 7mm wet suit and also dry suit (with AL80s only), and they will trim out fine with shoulder weights. It's a fairly standard solution. If lift wasn't a problem (I'm diving LP85s and AL40 deco bottle in 40s water), I'd still be diving the SMS 50 which is very travel friendly. Before getting the SMS 100, I weighed the option of the SMS 75. I like it a lot but its lift is still borderline for cold water diving, IMO. Hence the SMS 100. I implemented some of Edd's mods (esp. tightening the upper part of the bladder so that left biases toward the hip area) which works fine. Being a bit bulky is its main drawback. Not going on the plane as carry on.

I first tried the SMS 50 in Florida when I took side mount classes. The instructor immediately looked at my Hollis F1 fins and suggested that I would be happier with something lighter. I stuck with the F1s, but I did not like the SMS 50 and felt it did not have enough options for trimming out. I was able to overcome that and get myself in trim, but the instructor had an SMS 75 prototype I could use, and I immediately felt the difference and liked it. I did the class (and more) wearing it. Another student had the SMS 50 and heavy fins, and he was struggling with trim as well. Our instructor played with the design of the rig itself, making changes that really helped. I am having trouble visualizing it from memory because I no longer have an SMS 50 around, but I recall him playing with the waist strap design because as it was set up, it tended to put pressure on the bottom part of the bladder, forcing the air up toward the shoulder. I remember the instructor working with that student's trim, looking at me, calling me over, and showing me how the belt design was doing that.

I do agree with Bob, that with experience you can overcome it--I think the other student could have overcome that problem a lot with a little more skill work. He was not nearly as experienced as I.

I am still waiting for the SMS 75 I ordered to come in. If you are going to dive Florida, I suggest going with the SMS 75 or 100 instead of the 50.