Surface Marker or Lift Bag

[Scared Silly]

I did some looking but did not find anything on this.

I already have one surface marker that I use as back up lift when diving wet with doubles (It has 40lbs of lift). It works great and I am happy with it. I was thinking about getting a second one for the Mrs now that she is starting to dive doubles. However, I was thinking about getting a lift bag instead. I am wondering about the pros and cons of using one or the other.

To me the only cons for the lift bag is that being not as tall as the surface marker may not be as visable on the surface but it makes up for it being wider.

Also I have noticed that more and more mfgs have developed open circuit markers and lift bags with baffles. My SMB is closed curcuit which I like but it means using a lp hose to inflate at depth. So the open circuit has some appeal.

Note: Just for clarity I am not comparing small surface sausages with a lift bag and I purposely posted this in the Tech Diving forum rather than the Lift Bags and SMBs forum.

 

[cool_hardware52]

I did some looking but did not find anything on this.

I already have one surface marker that I use as back up lift when diving wet with doubles (It has 40lbs of lift). It works great and I am happy with it. I was thinking about getting a second one for the Mrs now that she is starting to dive doubles. However, I was thinking about getting a lift bag instead. I am wondering about the pros and cons of using one or the other.

To me the only cons for the lift bag is that being not as tall as the surface marker may not be as visable on the surface but it makes up for it being wider.

Also I have noticed that more and more mfgs have developed open circuit markers and lift bags with baffles. My SMB is closed curcuit which I like but it means using a lp hose to inflate at depth. So the open circuit has some appeal.

Note: Just for clarity I am not comparing small surface sausages with a lift bag and I purposely posted this in the Tech Diving forum rather than the Lift Bags and SMBs forum.

If I need to be able to add a large volume of gas to any inflatable I prefer an open or semi closed (baffled) bag. A purged S600 moves alot of gas in a hurry.

If you are using the bag for lifting a load then you need one with an OPV near the top. Open bags work great for lifting, and the chances of the bag dumping at the surface is zero as long as the load is still attached. The open bottom makes filling easy, and adding more gas if you vent a bit too much.

If what you seek is really a SMB then I prefer a semi closed (baffled) bag. It needs an OPV so it won't burst but it can be located anywhere. If you are using this bag as redundant buoyancy you need an OPV at the top of the bag so you can use it to make a controlled ascent.

Tobin

 

[jtivat]

I did some looking but did not find anything on this.

I already have one surface marker that I use as back up lift when diving wet with doubles (It has 40lbs of lift).

I would not recommend using either as back up lift from depth they are much harder to control and can be very dangerous.

 

[CompuDude]

If I need to be able to add a large volume of gas to any inflatable I prefer an open or semi closed (baffled) bag. A purged S600 moves alot of gas in a hurry.

If you are using the bag for lifting a load then you need one with an OPV near the top. Open bags work great for lifting, and the chances of the bag dumping at the surface is zero as long as the load is still attached. The open bottom makes filling easy, and adding more gas if you vent a bit too much.

If what you seek is really a SMB then I prefer a semi closed (baffled) bag. It needs an OPV so it won't burst but it can be located anywhere. If you are using this bag as redundant buoyancy you need an OPV at the top of the bag so you can use it to make a controlled ascent.

Tobin

Just curious: How would one hold onto a vertical bag (in the case of your average 6' tall SMB) near the top in order to manipulate the OPV during an ascent? (I've never tried, so please excuse my ignorance.) I understand quite readily the theory with regard to ascending with a lift bag, but it seems to me the height of an SMB would put the OPV out of reach.

 

[cool_hardware52]

Just curious: How would one hold onto a vertical bag (in the case of your average 6' tall SMB) near the top in order to manipulate the OPV during an ascent? (I've never tried, so please excuse my ignorance.) I understand quite readily the theory with regard to ascending with a lift bag, but it seems to me the height of an SMB would put the OPV out of reach.

I don't think you could do it with a tall tubular sausage type SMB. These need an OPV, but it can be anywhere. I would want to rely on a tall SMB for backup lift.

With a lift bag a cord to the bottom of the bag to remotely operate the OPV is commonly used.

It's still a real challenge to make a controlled ascent.

Tobin

 

[LG Diver]

Wow, this is something I have apparently not given enough thought to. I've been blissfully carrying around my 6' open bottom SMB thinking I have redundant buoyancy. My "plan" was to attach a spool, send the SMB to the surface, and then use the line to pull myself up. In retrospect, not sure if this is a workable plan. I certainly can see how controlling the buoyancy of a 6' SMB would be impossible. So, is something like this what I need for real redundant buoyancy:

http://www.halcyon.net/mc/liftbags.shtml

Looks small enough that I could hold on to it and reach the OPV, and the OPV is located at the top so it can be modulated. It can be filled from the bottom by purging a reg. Any other specific recommendations?

 

[cool_hardware52]

Wow, this is something I have apparently not given enough thought to. I've been blissfully carrying around my 6' open bottom SMB thinking I have redundant buoyancy. My "plan" was to attach a spool, send the SMB to the surface, and then use the line to pull myself up. In retrospect, not sure if this is a workable plan. I certainly can see how controlling the buoyancy of a 6' SMB would be impossible. So, is something like this what I need for real redundant buoyancy:

I agree that sending my "last chance" bag 'o' buoyancy off on the end of a line would be scary.

http://www.halcyon.net/mc/liftbags.shtml

I'm not sure about the bag in your link, (looks like a fine bag BTW) but some have the OPV installed backwards so the pull string is on the inside of the bag. This string is extended down to the opening in the bag. My Carter open bottom bags are like this.

What ever you decide on practice with it in safe conditions. Controlled ascents using unfamilar buoyancy devices are very interesting.

Tobin

 

[LG Diver]

I agree that sending my "last chance" bag 'o' buoyancy off on the end of a line would be scary.

http://www.halcyon.net/mc/liftbags.shtml

I'm not sure about the bag in your link, (looks like a fine bag BTW) but some have the OPV installed backwards so the pull string is on the inside of the bag. This string is extended down to the opening in the bag. My Carter open bottom bags are like this.

What ever you decide on practice with it in safe conditions. Controlled ascents using unfamilar buoyancy devices are very interesting.

Tobin

Tobin,

Which Carter open bottom bag do you have? My Carter 6' open bottom SMB has the OPV at the bottom, so it's apparently not appropriate for use as redundant buoyancy. I was checking out the Carter lift bags here:

http://www.golemgear.com/pc-174-5-carter-lift-bags-open-bottom-lift-bags.aspx

...but it says the 25, 50, and 75 lb bags don't have diver-actuated OPV's. I'd rather not have to carry a 100 lb bag for redundant buoyancy. I would think that a 25 lb bag would be perfect for this purpose.

What's everyone else carrying for redundant buoyancy?

 

[do it easy]

Just curious: How would one hold onto a vertical bag (in the case of your average 6' tall SMB) near the top in order to manipulate the OPV during an ascent? (I've never tried, so please excuse my ignorance.) I understand quite readily the theory with regard to ascending with a lift bag, but it seems to me the height of an SMB would put the OPV out of reach.

I did some impromtu lifting once with the TDL sausage- baffled bottom with the dump at the bottom. During the ascent, I would grab the top, pull it down and then use the dump to vent air. I wasn't lifting anything too heavy, so the bag wasn't bursting-at-the seams stiff.

It MIGHT be possible to use the bag upside down- the baffle seals well and there is a ring at the top, although I'm not sure how much weight I would trust to it.

edit: I might have misread your question, but I'm not sure if I've seen a tall sausage with the dump at the top?

What's everyone else carrying for redundant buoyancy?

I use my drysuit but I also carry a 6' Carter super sausage (no baffle) and a TDL sausage.

Getting back to the original poster- it seems like the distinction between a lift bag and a sausage is where you put the dump. Aside from the two sausages I dive with, I usually have a lift bag in my gear bag.

 

[cool_hardware52]

Tobin,

Which Carter open bottom bag do you have? My Carter 6' open bottom SMB has the OPV at the bottom, so it's apparently not appropriate for use as redundant buoyancy. I was checking out the Carter lift bags here:

50 and 100 lift bags, not SMB's The lift bags are the roughly triangular open bottom bags. These are great for lifting, tricker to "shoot" as they are prone to self empty if you don't maintain a constant load on the line. They do however have a top OPV with a sting run down the inside to the opening.

Tobin