UCFKnightDiver
Contributor
Have you tried saying/telling them "no" when they try to require you to wear the extra three pounds? It makes absolutely no sense to carry more weight than you need to sink/be neutral with an empty tank/500psi, as if you ditched the weight you'd still be negative.
The best way to think about trim is to think of your body in trim as a lever and fulcrum or a seesaw that kids play on. Now ask yourself how can I move weight or buoyancy around on my body closer or further away from my center pivot point/fulcrum to achieve a balance that would put you in horizontal trim. The further away from your center pivot point that weight and/or buoyancy is, the greater effect it will have on your trim. As others have said there's multiple things you can try if your feet are sinking and your head is floating, some of them are:
- Positively buoyant fins or fins that are less negative. This takes away some of the negative buoyancy from your feet and legs as they are already negatively buoyant and sinking.
- Position of the tank on your BCD - more forward/higher or backward/lower. I lean to try it higher, but the @The Chairman point about floaty rear's of aluminum tanks is an interesting one. This shifts the weight of the tank around to find better trim. Think lever and fulcrum/seesaw.
- Different BCD. Maybe an aluminum backplate and wing setup since you don't need more weight. This will get the buoyancy out of the shoulder straps that's making your head float AND put a pound or two of weight over your lungs/upper body which you said was floaty compared to your feet/legs.
- An ankle weight around the TANK NECK. This will add a weight similar to the way you're already doing with putting the 1.5 lb weight in your wetsuit/bra strap. This gets weight further forward to counteract your negative feet/legs. This will add weight that you said you didn't need, though I don't think a pound or two is a big deal. It will not be ditchable either.
- Body position. Get your feet closer to your body, knees bent at 90 degrees. Learn to frog kick from this position. Think of a lever and fulcrum or seesaw, this puts the weight of your feet closer to the fulcrum or pivot point of your body and reduces the effect your heavy legs and feet have on your trim. Also, arch your back and use your back muscles to bring your feet/legs up. Get used to the arched back position/feeling.
- Putting some trim weight up higher on your body, see @The Chairman post on weight on shoulder straps or use trim pockets. Heads up though, this will add more weight that you said you didn't need.
- Someone suggested making gaiters out of an old wetsuit that you would slide around your shins. Problem with this is the neoprene will compress at depth and you will lose some of the buoyancy, but it's an interesting idea.
I'm sure there are others, but I would try some of these ideas that people have given you. As you might have guessed, I'm not a big fan of the ankle floats idea as many materials will compress underwater and lose their buoyancy. If they're inflatable, then you have the same issue of the air compressing and losing buoyancy. Additionally, I don't think there are many options from various manufacturers out there.
Something else to think about regarding the weight is that if you're planning to dive salt water, then you may need to add weight as salt water is more dense and therefore things/people are more buoyant and need more weight to sink. I think you mentioned doing most of this work in a freshwater pool?
That was a bit long winded, but I hope all the information helps. Kudos to you for taking the time and energy to get your trim and buoyancy dialed in! Most people don't devote much time to it and they suffer for it in my opinion.
- Ryan
The best way to think about trim is to think of your body in trim as a lever and fulcrum or a seesaw that kids play on. Now ask yourself how can I move weight or buoyancy around on my body closer or further away from my center pivot point/fulcrum to achieve a balance that would put you in horizontal trim. The further away from your center pivot point that weight and/or buoyancy is, the greater effect it will have on your trim. As others have said there's multiple things you can try if your feet are sinking and your head is floating, some of them are:
- Positively buoyant fins or fins that are less negative. This takes away some of the negative buoyancy from your feet and legs as they are already negatively buoyant and sinking.
- Position of the tank on your BCD - more forward/higher or backward/lower. I lean to try it higher, but the @The Chairman point about floaty rear's of aluminum tanks is an interesting one. This shifts the weight of the tank around to find better trim. Think lever and fulcrum/seesaw.
- Different BCD. Maybe an aluminum backplate and wing setup since you don't need more weight. This will get the buoyancy out of the shoulder straps that's making your head float AND put a pound or two of weight over your lungs/upper body which you said was floaty compared to your feet/legs.
- An ankle weight around the TANK NECK. This will add a weight similar to the way you're already doing with putting the 1.5 lb weight in your wetsuit/bra strap. This gets weight further forward to counteract your negative feet/legs. This will add weight that you said you didn't need, though I don't think a pound or two is a big deal. It will not be ditchable either.
- Body position. Get your feet closer to your body, knees bent at 90 degrees. Learn to frog kick from this position. Think of a lever and fulcrum or seesaw, this puts the weight of your feet closer to the fulcrum or pivot point of your body and reduces the effect your heavy legs and feet have on your trim. Also, arch your back and use your back muscles to bring your feet/legs up. Get used to the arched back position/feeling.
- Putting some trim weight up higher on your body, see @The Chairman post on weight on shoulder straps or use trim pockets. Heads up though, this will add more weight that you said you didn't need.
- Someone suggested making gaiters out of an old wetsuit that you would slide around your shins. Problem with this is the neoprene will compress at depth and you will lose some of the buoyancy, but it's an interesting idea.
I'm sure there are others, but I would try some of these ideas that people have given you. As you might have guessed, I'm not a big fan of the ankle floats idea as many materials will compress underwater and lose their buoyancy. If they're inflatable, then you have the same issue of the air compressing and losing buoyancy. Additionally, I don't think there are many options from various manufacturers out there.
Something else to think about regarding the weight is that if you're planning to dive salt water, then you may need to add weight as salt water is more dense and therefore things/people are more buoyant and need more weight to sink. I think you mentioned doing most of this work in a freshwater pool?
That was a bit long winded, but I hope all the information helps. Kudos to you for taking the time and energy to get your trim and buoyancy dialed in! Most people don't devote much time to it and they suffer for it in my opinion.
- Ryan