Sounds like another "solution" in search of a problem. I can't imagine why the deflate process would need to be powered?
What happened - rapid ascent
- Thread starter mears
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Air will vent from the highest point. With a back inflate if you're leaned forward, air will be trapped in the BCD. Try leaning back and tilt to the side, placing the shoulder with the dump at the highest point . Also to stop your ascent swim down and use your butt dump, While you're inverted the butt dump will be the highest point.
Bob DBF
Contributor
Well, you started by saying you were somewhat underweighted. If you are underweighted, there will come a time during the dive where you can't stay down (unless you go head down and swim). It won't matter how many places you try to vent your BC, because it's empty. The reason for proper weighting is to avoid this.
Do a proper weight check -- that consists of weighting yourself neutral (or just negative enough to lie on the bottom in very shallow water) and then adding about five pounds for the gas in your tank. Either that, or you can do the check at the end of the dive, and determine how much weight it takes to be neutral in shallow water with an empty tank. Either way, proper weighting is the start. You can't blame your BC for buoyancy issues until you are sure you are weighted correctly.
Edited to add that, when a diver becomes aware of a problem, it is EXTREMELY common for that person's breathing pattern to change, as they hold more air in their lungs. This adds to the positive tendency and makes it harder to slow or arrest the ascent.
Do a proper weight check -- that consists of weighting yourself neutral (or just negative enough to lie on the bottom in very shallow water) and then adding about five pounds for the gas in your tank. Either that, or you can do the check at the end of the dive, and determine how much weight it takes to be neutral in shallow water with an empty tank. Either way, proper weighting is the start. You can't blame your BC for buoyancy issues until you are sure you are weighted correctly.
Edited to add that, when a diver becomes aware of a problem, it is EXTREMELY common for that person's breathing pattern to change, as they hold more air in their lungs. This adds to the positive tendency and makes it harder to slow or arrest the ascent.
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All tanks become more positively buoyant as the weight of air in them is decreased by you breathing it.
Technically i cant explain it but here goes any way. the power inflator is a hose from the wing to the operating end of the hose there is a Y in the end of it one branch of the y has the inflate valve and the lp hose from the regulator attached to it... Teh other is teh same except it has a mouthpiece on it instead of a lp hose from the tank. there is no remote control of the sholder vent. some have a wire that runs throught he hose to open the dump like the but domp operates. None of mine have that. with the power nflator you can push the inflate button adn it fills from your tank or you push the vent button and blow into the mouth peice to fill it manually. so the 2 braches i guess is a power fill adn the other is a manual fill / vent. You have guessed by now there is no POWER DEFLATOR only a power INFLATOR. And thats not a stupid question.
hope that answers how it operates.
hope that answers how it operates.
swimmer_spe
Contributor
I have a "power deflator". I press a button on the jacket and air comes out of the jacket. I also have 2 dump valves that if I need air out, I pull them. The older style is a valve at the end of a tube that must be put higher than the jacket to get any air out.
My read of this is the AL tank. One of the reason for diving steels.
My read of this is the AL tank. One of the reason for diving steels.
Selchie in LB
Contributor
Yes all tanks do become more positively buoyant, but aluminun tanks do not result in any negative buoyancy when air is depleted. I was making a general statement that aluminum tanks do not contribute to the negative buoyancy and can in fact add buoyancy at the end of a dive. Thus requiring an additional 2lbs of weight to counter the positive buoyancy.
When determining weight for diving, 10% of body weight plus 4-6 lbs for 7 mil suit. Jacket BCDs tend to be neutral to positively buoyant. Steel tanks can vary from 2-4 lbs negative when depleted of air. Aluminum tanks will be 2 lbs positive. The air adds an initial 6-8 lbs depending on tank capacity. The buoyancy check should be performed with a near empty (500 psi) tank. So in this case, I assume you rented tanks there and unless you specifically requested steel you got aluminum tanks. Being 2 lbs light to start resulted in 4 lbs light at the end of the dive. Being a new diver I assume that you are still working to control your buoyancy. It took me awhile. A new 7 mil wetsuit can make you feel like a cork! Keep a record of all your dives and gear and weight. It will be a good indicator of your buoyancy control and help you plan future dives with any gear changes.
under water some where
flots am
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All tanks have the same buoyancy change per cubic foot of air.
It doesn't matter if your tank is made from steel, aluminum or kryptonite. If you have used up 80 cubic feet of air, it (and you) will be 6.45 pounds more buoyant than when you started.
flots.
diver 85
Contributor
Add more weight & try again(with same setup).......If still same problem, could have a (slow) continuous leak in your power inflator head(you know, the part you hold).....
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