kawboy579:
I have steadily reduced my salt-water weight to 8 lbs after being certified. This is an acceptable amount of weight to allow me to submerge, however, with this small amount of weight i am having difficulty "bobbing" up and down as much as 5 feet between a full breath and an exhale while underwater. What can one do about this? Go back to more weight to compensate for this?
One thing you want to keep in mind is that most recreational divers are taught that 3 minute 'safety stops' are a good idea at the end of their dives. These become increasingly important as the dives become deeper, or as repetitive diving occurs - especially over several days in a row - such as on dive vacations or liveaboards.
Safety stops are performed when divers are ending their dives, typically with very little air left in their tanks. Its important to be able to hold those safety stops without a great deal of exertion - IOW, to be able to be neutral at 10' with very little air left in your tank (as Donacheson noted above).
If you must 'fin' constantly to hold your stop you're too heavy. But if you have difficulty in staying down and tend to float up uncontrollably, you're too light.
When you're 'weighting yourself', try doing it with your tank nearly empty. Luxfer aluminum 80s often used by recreational divers have 'swing weights' of ~4 lbs: i.e. the weight of the compressed gas consumed (down to 500 psi) makes the tank 4 lbs lighter during the dive. (cite:
http://www.divesales.com/tanks/index.html )
So, that 8 lbs you 'need' at the start of the dive when your tank is full may not allow you to comfortably hold a safety stop at the end of your dive when your tank is 4 lbs more bouyant. This can be a problem after several days of repetitive diving.
Get your weighting correct for the END of the dive. You may be slightly heavier for the start of your dive (by 4lbs or so), however it will pay dividends for holding those safety stops.
FWIW. YMMV.
