Ankle weights or Turtle fins

[Luis H]

IMHO ankle weights should not be necessary for adjusting trim. Trim can be easily adjusted by moving a weight belt up or down as needed (I tend to do that during the dive, if needed).

But, if your legs are buoyant, every time you do a downward kick you will be essentially doing inverted leg lifts. At the low speeds that you move your legs the inertia forces and kinetic energy related to the ankle weights is basically irrelevant. It is far more important for your legs to be independently neutral.

Again the issue of trim should be a totally different subject. Ankle weights if properly used to independently balance the buoyancy of a highly lofted drysuit can actually lower your energy use. Granted, most of the time you may not notice or be able to measure any difference.


I have used Jet fins for over 35 years and they are my favorite fins; but they do weight about 2 Lbs more than my other fins (which I rarely use). Most ankle weights are about 3 Lbs for the pair. If kinetic energy and inertia was an issue the weight in the fins would be far worst because of its location. The weight on the fins is further out than the weights on the ankles.

When it comes to energy use for a diver, drag, hydrodynamic forces, and hydrodynamic efficiency of the fins are the most important considerations, not inertia forces. We don’t move fast enough to be significant.

 

[RJP]

I was wondering what people’s thoughts were on either getting some ankle weights to reduce the buoyancy of my feet or should I consider getting some heavier fins like the Turtle fins?

At the risk of playing semantics here - neither of your proposed solutions actually REDUCE the bouyancy of your feet. Ankle weights or heavier fins simply OFFSET the bouyancy of your feet.

Don't treat the symptom, treat the underlying problem.

Have you tried/considered a pair of gaitors to keep the air out of your feet?

 

[Luis H]

I'm not a physics major, either. ....

Ankle weights add extra exertion to the kicks (if you don't believe it, strap ten pounds to each ankle and see what happens). This might be good if you want to build leg strength, but it isn't the best way to fix a trim issue, IMHO.

Well, I am not a physic major either, but I do have a couple of engineering degrees with a concentration in applied physics.
If you want to build leg muscles you could either add weights to make each leg 10 Lbs negative or add buoyancy to make them 10 Lbs positive buoyant. If your trim is correct, you will get the same work out.

Edit: Actually, you would be working different muscle groups, but that is a different subject (for which I am not qualified).

 

[Ann Marie]

I will stand by my ankle wieghts, I mean in....

Perhaps if I didn't have the hips that I have, I could trim out without them but I'm naturally more buoyant in some areas than others.

Hiya Matt :blinking:

Thanks for the mini-lesson Luis! :10:

 

[Luis H]

Hi Ann Marie

IMO ankle weights is just another tool (the major disadvantage of the weights is that it is another piece of gear to forget, to rinse etc.).

I have only tried the ankle weights to neutralize the buoyancy of the extremity (with my 7mm dry suit), not to adjust for over all trim. But, after several tests my results were inconclusive, so I don’t use them anymore. I even tried them on one ankle at a time to check how much of a difference it made on my kicking ( I didn’t have XL Jet fins at the time).

I can precisely adjust trim by moving my weight belt. My wife uses the same technique as me. Her weight belt used to slide on her whenever she changed position to being head down. She now uses a crotch strap attached to her backpack in back and to her weight belt in front. The advantage to this setup is that it not only controls the weight belt and tank in its set position, but if you ever need to ditch your weight belt it will not tangle with the crotch strap. I use the same set up, but basically to control my tank.