How to Set Up Double Scuba Tanks

How to Set Up Double Scuba Tanks
Scuba diving allows an individual to spend time where humans were not originally intended to go, but basic scuba diving times at depth are limited by one tank of air. Add a second tank to your equipment to expand dive times and depth ranges. To do so requires some additional considerations of equipment, setup and dive planning, beginning first with how to set up a diver's dual-tank rig. With the proper equipment, you can have expanded range and capability.

Instructions

Difficulty: Moderately Easy

Dual Scuba Tank Setup

Things You’ll Need:
  • Two scuba tanks Two opposite-facing tank valves Dual scuba tank bands Dual scuba tank backplate (buoyancy compensator backplate) Screwdrivers, pliers or wrenches as appropriate for hardware
  • Two scuba tanks
  • Two opposite-facing tank valves
  • Dual scuba tank bands
  • Dual scuba tank backplate (buoyancy compensator backplate)
  • Screwdrivers, pliers or wrenches as appropriate for hardware
Step 1
Set up each tank with opposite-facing valves. Each tank will have a single valve that has opposite-facing openings in addition to the standard regulator valve. These openings will be for a crossbar manifold valve to connect the two tanks. To complete this, screw in the appropriate valve to the top of each tank, making sure to tighten them snugly without stripping them.
Step 2
Install the crossbar manifold. To do this, first lay each tank down on a large hard surface with the primary valves facing upward and the opposite-facing manifold valves facing each other. Take the manifold cross valve and screw it in to each valve loosely. This will be done to both sides at the same time, so the two tanks will need to be close enough to each other that the manifold crossbar will reach each tank. Do not tighten this all the way down, just get it started; tightening will come later after the tank bands are installed.
Step 3
Put tank bands onto the two tanks. Now that the manifold crossbar is holding the two tanks together, the tank bands are slid up from the bottom of the tanks. There are two sets of tank bands that are needed. The first set will slide up to just a few inches below the crown of the tanks. With this band in place, you can now slide the second set of band up onto the tanks from the bottom. This set of bands will need to be placed in a measured position. Take your buoyancy-compensator backplate and measure the distance between the two mounting holes. This will be the distance apart for the screw holes that you will use to tighten the tank bands. With your measurement, slide the second set of tank bands up to a point where the distance between the top and bottom tank band screw holes is equivalent to the distance between the mounting holes on your buoyancy-compensator backplate.
Step 4
Tighten the tank bands. Each set of tank bands will have a screw, nut and wing-nut set that will be put in place and tightened down to hold the tank bands in place. Make sure the screw is poking through toward the side of the tanks that the valves are facing; this will be important when attaching your buoyancy-compensator backplate. You will likely need a screwdriver and pliers or wrench to do this. The sizes needed will depend on the particular hardware you are using. First, push the screw through the holes between the tanks on the tank bands, then thread on the nut from the side the tank valves face. Tighten this down until the tank bands are tight and do not slide. The wing nut can now be threaded onto the screw, but does not need to be tightened. This is only there for later using to holding your bouyancy-compensator backplate in place.
Step 5
Tighten the manifold crossbar. With the tank bands in place and secure, you can now tighten down the manifold crossbar between the two tanks. The manifold crossbar can be initially tightened by rotating it until the two tanks are evenly spaced in relation to the tank bands, then by using nuts on the bar itself. This will require a wrench. Each end of the manifold crossbar will have a nut that can be rotated to tighten its end up against each tank's respective valve. Do this to both sides. While doing this, be sure to keep the flow valve on the manifold crossbar facing up, do not allow it to rotate to another position. This will ensure that when the tanks are tightened that the flow valve will be accessible and out of the way. Again, do not over-tighten so as to avoid stripping. Snug is all that is needed.
Step 6
Install a buoyancy-compensator backplate. This will require removal of the wing nuts. Place your backplate onto the tanks so the holes in the backplate line up with the screws from between the tank bands. With this in place, screw on the wing nuts. Tighten the wing nuts to hold the backplate in place, but do not over-tighten them to the point of stripping. You should now be ready to use your dual scuba tank setup.

Tips & Warnings

 
Proper training when using dual scuba tanks is very important. The difference in weight, balance, and mobility is enough that it can be dangerous for uninitiated divers. Seek proper training from an appropriate dive training facility before using these setups.
 
Proper training when using dual scuba tanks is very important. The difference in weight, balance, and mobility is enough that it can be dangerous for uninitiated divers. Seek proper training from an appropriate dive training facility before using these setups.

Article Written By Jason Blair

Jason Blair is an active pilot and the executive director of the National Association of Flight Instructors. Blair actively writes in the aviation industry, primarily for the magazine Mentor, targeted at flight instructors.

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