Floaty Feet, always at end of dive

[Joris Vd]

Hello guys,

I am a novice diver, currently diving a 7mmwetsuit+5mm vest Diving a bp-wing configuration(3kg bp) with a double 7liter 232 bar and 7kg of lead. (in salt water,3kg less in sweet). My fins are Aqualung Stratos Fins.

Usually my trim is pretty decent, but at the end of the dive when we slowly go back up I always get the problem that my feet get MEGA floaty between 2-5 meters. It's been three times now that it literally completely breaks my trim and makes me hang like a buoy. making it very hard to get and stay into trim again. Like I literally have to fight myself into trim at the last five to ten minutes of a dive when we are doing all the necessary stops.


I was wondering if this is just inexperience and it's something you need to learn to deal with better or
maybe I should try to go for a negative fin or ankle weights??
I had just not really considered it, since I thought it was usually only a thing with drysuit divers?

 

[tbone1004]

if you're in doubles, use negative fins. Alternatively move the lead to a tail weight to do the same thing

 

[RainPilot]

I suspect the shift is to do with the relatively large amount of neoprene on your legs expanding, combined with a long moment arm from your centre of gravity. It’s less noticeable at the start since we don’t tend to hang around the compression depth long and are often vertical going through that range. Add in tanks getting butt-light at the end of a dive and it creates a big effect.

Heavier fins, tail weight should all help as tbone said.

 

[Bert van den Berg]

I had the exact opposite problem. Feet hanging down. Fixed it by moving some of the weight from the belt to the back, raising the steel tank a bit and using more "floatie" booties.

 

[seadweller]

How about heavier fins and ankle weights .
Good luck !
Sea Dwellers

 

[RyanT]

As tbone suggested, first try some heavier fins. I've got a pair of Hollis F1 fins that I really like, but they are HEAVY. I recently switched to a longer set of tanks and I now find the Hollis fins make me "foot" heavy. Likewise, putting a kg or two in a tail weight pouch will probably work as well.

 

[0321tony]

If you are diving aluminum tanks they become buoyant at the end of the dive and could be causing your problem. Next time you dive stop at the 15ft depth on your descent and check your trim to see if you still have floating feet and adjust if you need to.

 

[DevonDiver]

Minor under-weighting often presents as floaty feet, especially with thicker wetsuits and/or AL cylinders.

There's a big difference between having a slight tendancy for the legs to drift up or down (trim tuning) and a powerful force pulling the legs up (weighting problem).

It's important for the diagnosis to note that the issue only arises at the conclusion of the dive, where there is minimum gas and maximum buoyancy from exposure protection.

Again, that variance points strongly towards a weighting, not trim, issue.

First step is to conduct a proper weight check - get neutral with no air in the BCD at shallowest stop on minimum gas (I use 35 bar as reference).

After weighting is confirmed sufficient, fine tune your trim by shifting weights and/or swapping fins for a heavier set... although this probably shouldn't be necessary.

I'm assuming you've done a weight check already and got your lead down to a bare minimum. You're probably a lb or two under. If you had any gas in the BCD on the last stop, you'd be able to move the bubble to the top of the wing and resolve a trim issue. You haven't mentioned that.. do I'm guessing there's no gas available to do so.

Again, recheck your weighting and see if a lb or two extra solves the issue.

 

[scubafanatic]

Apollo Bio fins are 'negative', being 100% pure rubber.

 

[stuartv]

As tbone suggested, first try some heavier fins. I've got a pair of Hollis F1 fins that I really like, but they are HEAVY. I recently switched to a longer set of tanks and I now find the Hollis fins make me "foot" heavy. Likewise, putting a kg or two in a tail weight pouch will probably work as well.

Shifting your wing position on the back plate down (so the lift is more aligned to the tanks' center of gravity) might help.

If not, the F1 LT fins are just like the F1s, only less negative.

My F1s are size XL and are -2.0#.

My F1 LTs are size L (Regular?) and are -1.0#. All measured in fresh water.