Lift bag advice needed

[lhpdiver]

Today I did the first 2 dives for Search & Recovery class. My 5th specialty and best so far. Actually found 2 weight belts (and an old useless outboard). I used my newly purchased Dive Rite 100# lift bag. To get back to the anchor line I had to swim against a wicked current. The lift bag really made the swim tough (all the extra surface area catching the current). I was kicking hard, grabbiing the bottom and pushing the lift bag line with my shoulder like a tackling sled. I was exhausted when I reached the anchor line (which was attached to the deck of a wreck). When the lift bag was about 10 feet off the bottom I started to feel it pulling up hard. I started pulling on the purge but no air was released. My instructor came over and "helped" the air out as the air level was "higher" than the purge. He tethered the lift bag line to the anchor line and we shimmied it to the surface. My question (finally) is this - I want to always have a lift bag attached to my BC - but today's experience has me wondering if 100# is the best choice. It's like a 50# bag can't lift as much as a 100# bag (obviously) but a 100# bag isn't right for smaller weights.

Any advice/suggestions/comments appreciated.

 

[DA Aquamaster]

A smaller bag might have a little less wetted area but the volume of air required to lift what ever it is you are lifting will be the same so you won't save quite as much drag as you would think. And most smaller bags do not have a dump valve.

I have never had a problem with my Carter 100 and 200 lb lift bags - they have the dump valve very near the top and will dump all but about the last 5 lbs of air and that is easily dumped by inverting the bag.

I normally send the bag up with a wreck reel or attach the bag around the flag line with a locking carabiner if I am dragging a flag. It still pulls in the a current but much of the bag is above water and you do not have to mess adjusting the bouyancy of the bag. You also pick up some drag from the line, but unless the current is really ripping at the surface, it is easier than messing with it on the bottom.

 

[Wreckie]

First i think that you shouldnt be riding the bag up at all if you can help it, let it go and see it on the surface, however unless theres some way to get it back, either have the boat collect it or connect it to you via a reel, then your stuck.

Go buy another dump valve and put it further up the bag so you can dump from whichever is appropriate for the amount of air you have at the time.

Mike

 

[NEWreckDiver]

Today I did the first 2 dives for Search & Recovery class. My 5th specialty and best so far. Actually found 2 weight belts (and an old useless outboard). I used my newly purchased Dive Rite 100# lift bag. To get back to the anchor line I had to swim against a wicked current. The lift bag really made the swim tough (all the extra surface area catching the current). I was kicking hard, grabbiing the bottom and pushing the lift bag line with my shoulder like a tackling sled. I was exhausted when I reached the anchor line (which was attached to the deck of a wreck). When the lift bag was about 10 feet off the bottom I started to feel it pulling up hard. I started pulling on the purge but no air was released. My instructor came over and "helped" the air out as the air level was "higher" than the purge. He tethered the lift bag line to the anchor line and we shimmied it to the surface. My question (finally) is this - I want to always have a lift bag attached to my BC - but today's experience has me wondering if 100# is the best choice. It's like a 50# bag can't lift as much as a 100# bag (obviously) but a 100# bag isn't right for smaller weights.

Any advice/suggestions/comments appreciated.

First off, remember that your safety always comes first. There isn't anything worth that much to get you exhausted and possibly getting yourself in an OOA situation.

I most cases, when you send up a bag, you send it up from its current location. Remember, the boat can always go and get the bag or they can send out a swimmer to retrieve it. Never tie it to the anchor line. Think about what may happen if the tie came loose and the motor fell on people doing their hangs on the anchor line.

What did you mean by “having the bag attached to your BC”? If this is for stowing, then roll it up and clip it off to a location that will not allow it to get hung up in something in the water and that will allow you to deploy it easily.

Good Luck and be careful.

 

[nyresq]

Only use a bag that is just big enough for the object you're lifting. It may seem easy to just get a 200lb bag "cause it'll lift what ever I need" but if you're lifting a 40lb anchor a 200 lb bag is overkill. A bag too large will start to accelerate as the air inside expands. A dump valve may or maynot be able to keep up with the rate of expansion. for general diving a 50,80 or 100lb bag is good. I especially like the halcyon closed 80 lb. its good for an up-line and rolls compact enough to keep anywhere on your plate or between your tanks. the closed design keeps it from dumping if it hits the surface a little too fast.
If your going to start lifting things on a regular basis, then go out and buy a few different sized bags to use. there is no one size fits all when it comes to lift bags. For an up-line or lifting a small anchor, a 200 lb is overkill, but for lifting a large outboard a 100 may not be enough.
I definatly agree that a line is needed anytime a bag is used, attaching it to the anchor line is stupid and dangerous, and will get other divers very pi$$ed at you. The bag only has to go a little too fast for you to loose control and at that point its gone.

buy a reel to go with the bag, and practice shooting the bag up with a reel away from the anchor line. for general purpose an 80lb bag is a good comprimise

 

[lhpdiver]

Thank you all for your replies.

Part 2 of my adventure comes up Saturday morning and I'll make sure we practice sending the bag up using my safety reel. I'll contemplate a second purge but if I'm not going to be with the bag on the way up the purge seems less important. I've got the bag in a velcro pouch at the base of my backpack. One thing I do need to get a carabiner. At one point last weekend I attached the lift bag to a cinder block using a (new) stainless steel ring and before I knew it the expanding bag straightened out the ring (sending the bag to the surface

I guess once you send the bag up unescorted you either surface shortly thereafter or find yourself looking up pretty often.

Oh and NEWreckDiver - regarding OOA - I normally breath very well. I wasn't out ... but I was sucking my instructor's air on the safety stop.

 

[NEWreckDiver]

Thank you all for your replies.

Part 2 of my adventure comes up Saturday morning and I'll make sure we practice sending the bag up using my safety reel. I'll contemplate a second purge but if I'm not going to be with the bag on the way up the purge seems less important. I've got the bag in a velcro pouch at the base of my backpack. One thing I do need to get a carabiner. At one point last weekend I attached the lift bag to a cinder block using a (new) stainless steel ring and before I knew it the expanding bag straightened out the ring (sending the bag to the surface

I guess once you send the bag up unescorted you either surface shortly thereafter or find yourself looking up pretty often.

Oh and NEWreckDiver - regarding OOA - I normally breath very well. I wasn't out ... but I was sucking my instructor's air on the safety stop.

Good Luck with your next dive.

I wasn't making a derogatory comment about your air consumption, but I guess you already know what happens when you get exhausted so I won’t say anything more.

If you know you have a tricky lift, you may want to consider a length of rope that is runs through a piece of tubing and loops at both ends of the rope. This will give you a nice loop of rope to run through your piece and clip to the bag. It also makes it quite secure so you don’t have to worry about it coming back down on your head.

If you send it up with a reel, don’t forget to make sure the line is long enough. You don’t want to go for that really quick ride to the surface once the line gets to the end. (I’ve seen guys do this) And once you send it up with the reel clipped off to it, you can at least keep it within a couple of hundred feet from the boat at least.

DSAO