Seriously, though... you're wearing your weights too high

[crofrog]

I can tell also by the amount of air left in the wing when I descend. If I empty all the way I sink to fast to keep up with ears and drysuit. I'm overweighted.

What undergarments do you use.

 

[formernuke]

What undergarments do you use.

Right now the pinnacle thinner ones, soon I will transition into fourth element artics.

 

[OTF]

An additional thought:

The gravitational mass of heavy fins is largely offset by buoyant forces underwater but inertial mass is unchanged.

If you’re going to be doing a long swim, you might want to think about the extra work required to repeatedly kick with heavy fins.

Ive never had issues but I’ve seen several others have fatigue problems exacerbated by using heavy fins. YMMV

At the risk of approaching off-topic-enough-to-be-a-new-thread territory I think this is a fascinating point that deserves further hashing out. I've thought about this a lot but seen relatively little discussion of it online. In theory it should be more efficient to correct trim by adjusting the location of weights/wing/tanks and diving light fins rather than going with the heaviest possible fins or (god forbid) ankle weights just to correct trim.

 

[oya]

I'm 6'5"

My feet are really far from my center-mass and need their own buoyancy control.

But I do have orangutan arms that could reach tank valves if I lowered my tanks significantly enough to wear a floaty fin.

A person who is 5'5" will not have orangutan arms and wouldn't be able to reach down their back quite as far. Also, they have a much smaller torso, one where there isn't a lot of real-estate to move tanks or wings around.

To those ends, negative fins, in my experience, tend to be the solution for most.

I would suggest anyone who is actually claiming fatigue due to a fin that doesn't float, would do will to work on kick efficiency. And/or start doing some sort of leg exercise.

 

[crofrog]

Fins are movable trim weights. There is more to being in trim than just being flat. Having heavier fins let you do more to balance by moving your legs in and out

 

[lostsheep]

I would suggest anyone who is actually claiming fatigue due to a fin that doesn't float, would do will to work on kick efficiency. And/or start doing some sort of leg exercise.

I feel like that was directed at least partially at me so let me reiterate , I have never had fatigue problems but I have seen it several times.

You keep referencing gravitational mass which is largely negated by buoyant forces. I’m talking about inertial mass. They are not the same thing.

If heavy fins work for you, by all means have at it. Having the mass on the long lever that is our legs let’s you really fine tune your CoG mid dive, but it is a trade off. That is the extent of what I’m saying.

Lastly and most important , swimming sucks, get a DPV

 

[crofrog]

Lastly and most important , swimming sucks, get a DPV

Swimming is for peasants

 

[211ratsbud]

Listen I read through this whole thread including the OP. My rebreather has me dragging my knees quite a bit with 10lb at the top of the oxy and Dil total and 6lb at the bottom. 16 lb total on a p2 inverted tanks arctic underwear and rk3 hd fins. The standard fins don't have enough ass for the river.

I can't imagine moving the weight lower. But I'll try lol

I need some coaching halp!!

 

[happy-diver]

Yes heavy fins lead to unnecessary effort for no result whether you have the leg strength or not
Go on get fatigued, increase your Lactic Acid Build Up: What It Means and How to Get Rid of It - Orthopedic & Sports Medicine. and the potential for DCS. Yeah chase that trim, with heavy fins

 

[Tournesol2000]

Seems so counter intuitive but if it means putting my tank lower to achieve balance, it is worth trying.
Thank you for sharing this.