Trouble descending in horizontal trim with new fins

[DrWilliam]

I recently switched from Atomic Split fins to Deep 6 Eddy because I wanted to learn to properly frog kick. Did 25 dives with the Eddy's and LOVE the proper control and power. I also should say I feel I am perfectly trimmed and weighted at depth. However, I noticed a problem descending and it took me a while to figure out what is happening. I am rotating to head down orientation during descent while attempting to descend in horizontal trim. At first I couldn't understand it because I am properly trimmed once at depth, but during the descent it felt like I was head heavy. What I am almost sure is happening is the massive "paddle" of the new fins are resisting the water during decent and hence rotating me to a head-down orientation. I can't figure out if there is some special way to "dump" the water from the fins or a different position to keep my legs in during descent. I tried some things but this was a persistent problem. Even trying to manage it almost made it worse because just a little ankle "flick" with these fins has a significant input on the water.

These fins are so much better for scuba and I will definitely be sticking with them, but I did find they really really sucked for surface swimming compared to Splits.

Any tricks?

 

[steinbil]

What kind of exposure protection do you have? Drysuit or wetsuit? Are you perfectly trimmed at depth when lying completely still and not swimming or moving legs? What kind of tanks/gear are you using? How fast are you descending? What is your leg position when you're descending? How do you initiate the descent from the surface?

I've never experienced this, but I'm not convinced by your theory. If it is just the resistance from the paddle, the solution is super simple: bend your knees 90 degrees and extend your feet (straighten your ankle) so the tips of your fins are pointing straight up. From this position you could even flick your ankle to create downward momentum through your legs.

Apparently the Eddy fins are neutral while the Atomic splits are slightly negative. Don't know if that contributes. If you have a thick wetsuit and your legs are somehow on the surface when you initiate descent (which makes no sense since you need to vent the BC head up), maybe the uncompressed neoprene around your legs and the surface tension throws off your balance. I'm wondering if you might not be weighted/trimmed correctly or if you're doing something weird with your legs during descent.

 

[-JD-]

You might try bending your legs up at the knees and pointing your toes to orient the fins more vertical. Ankle angle can adjust to control your lower half descent drag to maintain trim.

Atomic splits ard my favorite snorkle fins - short fluttereing strokes to flex the blades instead of slap-slap-slap.

 

[DrWilliam]

What kind of exposure protection do you have? Drysuit or wetsuit? Are you perfectly trimmed at depth when lying completely still and not swimming or moving legs? What kind of tanks/gear are you using? How fast are you descending? What is your leg position when you're descending? How do you initiate the descent from the surface?

I've never experienced this, but I'm not convinced by your theory. If it is just the resistance from the paddle, the solution is super simple: bend your knees 90 degrees and extend your feet (straighten your ankle) so the tips of your fins are pointing straight up. From this position you could even flick your ankle to create downward momentum through your legs.

Apparently the Eddy fins are neutral while the Atomic splits are slightly negative. Don't know if that contributes. If you have a thick wetsuit and your legs are somehow on the surface when you initiate descent (which makes no sense since you need to vent the BC head up), maybe the uncompressed neoprene around your legs and the surface tension throws off your balance. I'm wondering if you might not be weighted/trimmed correctly or if you're doing something weird with your legs during descent.

5mm full wetsuit. Perfectly trimmed at depth with nil air in wing while lying completely still. AL80 on a steel backplate. Descending I would estimate at 20 m/min. Leg position during descent is legs 90 degree and ankles 90 degrees. Initiate descent by emptying wing at surface and then just sort of rotating into horizontal trim while exhaling.

You're correct about the Split fins being negative and the Eddy's being neutral (It's another reason I went to the Eddy's - had been previously foot heavy). I may just be adjusting to the lighter feet on descent, but like your mention about me being trying to point my toes to angle the fin blade up.

 

[ginti]

You say you "feel" your trim is perfect at depth. Have you tried it only while swimming, or have you actually stopped to stay completely still and motionless?

 

[DrWilliam]

You say you "feel" your trim is perfect at depth. Have you tried it only while swimming, or have you actually stopped to stay completely still and motionless?

Yes sir, I would confidently say so. This problem is rather dramatic during descent. I'm dropping head down while passively descending and not moving. I'm very confident its the fins because I can easily make it worse with ankle dorsiflexion (which I think I'm instinctively doing even though it would be the opposite of what I should be doing). I probably over estimated my descent rate above even (because sometimes I actively descend / swim down). When just using breath control and weighting I probably descend more like 10 m/min max. Once at any given depth I can remain motionless in horizontal trim and zero depth change with zero input of fins (or ok I admit, a little bit of those subtle minor muscle twitches on the fins). I also reviewed video of my trim while remaining still. But basically I'm saying, my trim and buoyancy are dialed in and this problem developed noticeably when switching to these massive flat paddles on my feet. If it help for diagnosing, I am easily able to stay in horizontal trim for safety stop and for even a VERY slow 2 min ascent from 3m to surface

 

[Learner Diver]

this problem developed noticeably when switching to these massive flat paddles on my feet.

I've read and have discussed with my LDS that split fins are fantastic for new divers who struggle with wider fins. Do you intend to switch back?

 

[grantmac]

I've read and have discussed with my LDS that split fins are fantastic for new divers who struggle with wider fins. Do you intend to switch back?

Find a different LDS, that advice is awful.

To the OP: what is your hand position?

 

[DrWilliam]

Find a different LDS, that advice is awful.

To the OP: what is your hand position?

I will not switch back to split fins. I truly wish I had been given better advice to choose tech type fins when I started. These fins are THE tool for scuba. As I mentioned they are not ideal for snorkeling IMHO although you can get by.

My hand position Is usually standard out front, like a skydiver's position in free fall. I sometimes use my hands weight as a tool in the quiver to vary my trim, for instance if I want to shift weight. I will bring them back to my sides momentarily to go head down (intentionally). Essentially shifting a few minor pounds of trim dynamically

 

[NW Dive Dawg]

Did 25 dives with the Eddy's and LOVE the proper control and power.

I'd say that the fact that you love the proper control and power during your dive is far more important than any concern about having a less than "perfect" horizontal positioning on descent.

To be honest, unless there's a real need or requirement for a "negative" entry......I prefer descending feet down so I can easily rotate 360, look up, look down..... and have better situational awareness if I'm in a group. The people or agencies that insist or promote that a perfect horizontal "skydiver" position while you strain your neck to put the back of your head on your ass ...... have forgotten that the primary reason most of us do this is to just to have fun ......