Ankle weights

[b1gcountry]

I am wearing Atomic Splitfins and I think they are quite buoyant especially when combined with the neoprene booties.
I have another issue...sometimes I find myself rolling a bit to one side? Any ideas why that happens?

BTW, what is "trim"?

The fins/booties probably aren't overly buoyant compared to the average person. The ankle weights are a solution to a problem, but a lot of times better solutions can be found. The ankle weights are just a way to move ballast down lower on your body. The same thing can be done by moving some of your lead lower on your torso. You can try moving around with a weight belt vs integrated system, moving your tank around, or by doing any of another dozen or so little things.

What sort of position are you actually in when you're in the water. A lot of instructors see students with their feet down as the norm, so if they see someone who is actually horizontal, they think something is wrong.

Another thing, if your feet rise a little, you can usually bend your knees and the buoyant force in your feet won't have as long of lever arm to act on, so it effectively reduces the tendency to put you face down. When I dive, I like to keep a little bit of air in my drysuit boots. It makes my feet a little buoyant, and kinda feels like I'm being held up in the water by little strings from my feet and by my shoulders. It feels stable.

Another thing (yes, another one) You're probably diving in a wetsuit at this point. You also probably are staying quite shallow. The buoyancy characteristics of a wetsuit are pretty much at their worst in 20' or less. As you get deeper, the buoyancy in your feet tends to get less and less, and the boayancy centered on your BC tends to increase. It's quite frequent for someone with floaty feet at 20' to have heavy feet in 80'. Especially in heavy wetsuits.

All these trim issues need time to work out. The more time in the water you have, the more comfort you are going to have, and the better and easier your trim and buoyancy becomes. You can deal with a lot of minor instabilities when you have enough dives under your belt. I wouldn't jump to an equipment solution at this particular point.

As to the rolling, I agree with R stoffer above. It is a lot of times just due to a tank that's a little loose. A steel tank also likes to roll you over on your back whenever you aren't staying flat in the water.

Tom

 

[TSandM]

The tipping from side to side thing isn't uncommon. It's due to a combination of factors: the tank, which is your largest mass and fairly negative, has a strong desire to head for the bottom. If it's in the middle of your back, it will stay there, but if you get just a little off kilter, the tank will strongly tend to keep you turning onto your side or back. If your BC is a little loose on you, it makes it VERY easy for the tank to get off center on your back, and then it will take you with it.

It's a little like riding a bicycle. When you learned to do that, you learned to balance a large mass on top of a very small support. You have to do the same thing in diving, and after a bit of practice, you will find you unconsciously move your body to keep the tank centered. A BC that fits well will minimize the problem, and stability of the tank is one of the reasons so many of us love backplate setups.

 

[b1gcountry]

PS, the price you paid was not terribly high. That seems pretty standard. The cheapest I've ever seem them even online was about $19.

Tom

 

[rstofer]

If you are doing beach entries, having fins that float is not necessarily a bad thing. I have been told that, sometimes, people lose track of a fin while they are putting them on. Now, that has never happened to me (and I certainly wouldn't admit it) but it is something to consider. Floaty masks would be another good idea...

I am not advocating for floaty fins but for new divers first encountering a dynamic body of water, they can be helpful.

Richard

 

[TSandM]

THIS page has a couple of good articles about static balance -- the effect your equipment has on your ability to remain horizontal.

A large part of your balance can be achieved with your body posture, but physics is what it is; if you put a heavy weight (eg. a steel 72, the tanks my LDS uses in the pool) near your head, the front end of you is going to sink unless that weight is countered somewhere on the other side of your center of gravity. It is a big issue in the pool, because someone in minimal or no exposure protection is going to require little or no weight to sink with a steel tank, so there isn't a lot of additional ballast to move around.

If your posture is good -- stretched out, body flat, hips extended, head up -- and you tip head down, then you can try moving the tank down, but you may well need some counterbalancing weight on your feet. Negative fins do it, but ankle weights are cheaper.

Much of this will change when you get to open water, because you may well be using different tanks and different exposure protection, and need a different amount of weight. But each combination of tank, BC, exposure protection and weight will have to be balanced. Once you have dived for a while, you will know how to set yourself up for different diving conditions. I have, for example, different weight belts for single and double tanks, and a whole different BC setup for warm, tropical diving with a single Al80.

 

[GrumpyOldGuy]

There a lots of ways to recycle old ankle weights.
1) They make a very good sap (weapon) if you want to knock someone silly
2) You can use them as a trim weight around your tank valve
3) They can hold down a corner of a tarp

Seriously, keeping your weight closer to your center of gravity (belly button) is much more desirable than adding weight to your extremes. Diving is very dynamic and you still have to control the interia from the mass of the weight even if the forces of gravity are reduced in water. So anytime you add weight as the extremes (like your ankles) you are just creating more work for yourself, it is better to shift you main weight slightly.

I am not saying ankle weights are never needed, just that are a last resort and are over prescribed as a quick fix to an underlying problem that might be better addressed with other adjustments to your configuration.

 

[cmburch]

I used ankle weights for several years, but it was to get some weight off my belt for hiking.

I still bring them along in case someone needs some extra weight.

They may fit into pouch type weight belts so they can be used as soft weights if you do not need them in the future.

 

[MaxBottomtime]

Lynn is correct about the backplate. Tank stability is my favorite feature of a backplate and the main reason I got rid of my BC about ten years ago. Jetfins solved my fiancee's problems with floaty feet, but if you feel you need ankle weights you can get some at any sporting goods store for less than ten dollars per set. They use the same ones for weight training.

 

[Colliam7]

I just completed my confined water dives today and the instructor told me I needed ankle weights ... Are these really necessary or is this a bunch of BS?

As several have posted, there may be situations where your legs are positively buoyant, and a shift in weight is appropriate. In general, I have had better success with heavier (more negative) fins, than with ankle weights.

There a lots of ways to recycle old ankle weights. ... 2) You can use them as a trim weight around your tank valve

Actually, they can also be clipped around the bottom of an AL80, above the boot. I find this is a useful alternative to placiong them on the ankles of student divers.

Seriously, keeping your weight closer to your center of gravity (belly button) is much more desirable than adding weight to your extremes. ... So anytime you add weight as the extremes (like your ankles) you are just creating more work for yourself, it is better to shift you main weight slightly.

Well stated. For this reason, among others, putting ankle weights on ankles is usually not a preferred solution. In fact, it is also a reason I generally don't use them around the tank valve. Putting them on the bottom of the tanks places the weight lower than your weight belt, but not as low as your ankles. Your purchase was not necessarily a bad idea. However, I might use them in ways other than placing them around your ankles.

 

[Artimas]

I do think ankle weights can be useful and wouldn't dismiss them out of hand.

I have very buoyant fins, and my feet do float because of them along with my neoprene booties. I tried ankle weights during my last dive, and they helped a lot. I took 3# off my waist to compensate, and my overall trim was better.