Lift Bags

[Lukas]

So I want to make my own lift bags and SMB's, does anyone know where i can get dump valves and lp hose connectors, etc? And what would be the best, sturdiest material to make one out of? Also, why do you even need a dump valve on an open-bottom lift bag?

 

[mthirsc]

The dump valve is to let air out as it expands when you are slowly bringing something to the surface, to prevent the object from making an uncontrolled ascent, and taking you with it. I suppose if you are using the bag to shoot a line or send small objects to the surface by themselves you don't need it.

 

[Lukas]

Does anyone know where i can get a manual dump valve??? Ive been looking all over but can't seem to find anything.

 

[mirrocraft]

your best bet is to get one off an old bc with the pull cord or on ebay you may find one as well since you are custom making this you can use one off any bcd also if your wanting to lift thing really heavy we use plastic 55 gallion drums that we modify to do the job down fall to this is you cant release the air but you connect a come along to it and you can release cable that way

 

[1_T_Submariner]

Just curious about this. I theory you should be able to lift 440Lbs with a 55 Gal drum. Is this accurate? 6-8 of them to lift an average 3500 lbs car?

your best bet is to get one off an old bc with the pull cord or on ebay you may find one as well since you are custom making this you can use one off any bcd also if your wanting to lift thing really heavy we use plastic 55 gallion drums that we modify to do the job down fall to this is you cant release the air but you connect a come along to it and you can release cable that way

 

[Thalassamania]

You can get most of that stuff from Trident (but you have to go through an LDS).

 

[Brand0n]

yes 55 gallon drums make great lift bags, cut open the bottems, and put a gate valve on top to let air out

 

[Bob3]

Quick & dirty lift bag = goodie bag with a kitchen size plastic garbage bag inside.
Hit your local pawn shop; they very often throw away crappier BCs; there is a lot of usable hardware on them yet.
I like the 1 cubic yard "dry material handling bags"; they've got a lot of lift & are dirt cheap [if ya need anything that big]. 1700 lbs lift, approximately.
Check with your local sandblasting sand supplier.

(turn it upside down & it's a heck of a lift bag)

 

[NEWENGLANDCHARTERS]

55 gal poly barrel. Drill holes around the top lip (the End with the holes) in all four quadrents. Lace a harness of 3/8 nylon line around the entire barrel and thru the holes. Then harness the circmfrance the the upper and lower and middleflats areas.

If I could post a picture I would. I just made a dozzen of these riggs to float some Granite Moorings in Camp Ellis, Saco, Maine. Anybody want to help? January, Febuary or March. Im waiting for good tides.

These Barrels have a volume of 55 galoons in theroy. Figure 50 Gal at 8 pounds per gal of water and you get 400 pound of lift from each barrel. Calculate on the safe side as its not a perfect world. Figure the bouancy diffential of the water on the item you will be lifting and fudge in and residual suction from mud ect.

Drill and thread a PVC ball valve into the Bung Plug and Glue the Plug and valve back into the barrell bung. The harness should have the lift points on the bung end. but also add a control line on the solid end.

You can hook up and air compressor to the valves or just close them to use the power of the tidal lift.

Yes they work and they work well and cost next to nothing

" Give me a Lever and I can Move the World"


http://home.maine.rr.com/newengland/

 

[james croft]

I carry a commercialy built 100# bag when diving as it stows neatly. But for big jobs I have used a lot of stuff that are more bulky, but the price is right. One problem on improvised lifts is venting them in a controlled manner. I've used the pressure release type valve found on old hot water heaters. Screws right into the bunghole on a 55 gal drum. Makes venting a cinch. Also a good way to rig drums is as a pontoon. The cylinder is on it's side rather than up and down. To rig it, cut a small "mouse hole" near the rim at each end of the drum directly opposite from each other. Run your strap through the drum at the mouseholes. Locate the mouseholes so they are also opposite the bunghole , which will be used as a vent with a valve screwed in it. When filled with air, the drum is sideways, the mouseholes are towards the bottom of ocean with strap running through them and attached to the object to be lifted. The bunghole is located at the upper side of the cylinder and air can vent through the pressure release valve.
Also an innertube is a handy liftbag. Cut through an innertube so you have a horseshoe shaped cylinder. Run a strap through it. Add air , instant lift bag. Excess air vents at the two open ends of the innertube.