Securing tanks

[divezonescuba]

Here are the plasteak, starboard, pvc, and 2x4 basics benches.

The pvc tubes can be removed so that different size tanks can be accommodated. I have the rails for the adjustable roll control holders, but am still debating on whether I really need to use them.

After looking at TREX decking and pressure treated lumber, I decided to go with the Plasteak 2 x 4s so I would never have to replace or refinish them. I used the 2x4 basics legs for liability purposes. I put an extra leg between the two end supports although you can actually use the legs up to 8 feet apart. The result is a rock solid bench. The legs are thoughbolted to the deck.

The horizontal piece of starboard that holds the tanks is throughbolted to a vertical section of plasteak that is attached to the rear most 2x4 board. Another piece of starboard is attached vertically to the horizontal piece of starboard. This is through bolted to the side of the coaming.

There is one of these on each side of the cockpit. Because the cockpit is relatively small, the benches are only 3 feet long. Although 3 BCs can be mounted on the tanks on each side, only two divers can put on their gear at the same time.

 

[SkipperJohn]

what size PVC did you use and where did you get it?

 

[divezonescuba]

I had to go to a plumbing supply distributor. Home Depot, Lowes, and local hardware stores did not have that size. The outside of the pipe is about 8 inches in diameter. If they are not split, only AL80s will fit. You cannot use the hexagonal tank boots. However, round tank boots fit fine.

I cut a 2 inch slit in pipe for some of the other holders so that they could expand for AL100s and steels.

 

[mitsuguy]

did you use schedule 40 or 80?

I have been tooling around with the possibility of building new tank holders similar to yours for our Newton 36 (currently all we have is a plastic ring at the bottom and then a bungee, which is not favorable) According to the specs, Sch 40 is 7.981" internal diameter, Sch 80 is 7.625" internal diameter - obviously the 80 is stronger, but is the .375" enough of a space for the tank and any strap that might be low enough to matter???

 

[divezonescuba]

We used schedule 40. It is quite robust.

Schedule 40 allows for the use of tank boots that have round rather than hexagonal tops. We have converted all of our tanks to the round top boots since we have to use them both for the pool and the boat.

Ours are 15 inches high. On our last trip, they worked out quite well.

We had one interesting situation with one of our customers. When I spoke to that customer he said that he had one steel "100" and two steel "72"s. He said that the 100 was 8 inches and that the 72s were the same. It turned out that the 72s were a lot smaller. The "100" had a tank boot, but the "72"s did not.

Fortunately, I had only removed and converted one side of the bench to the curved roll control mounts. They worked ok for the 100, but not for the 72. We ended up putting the 72s in the pvc holders and used the curved holder for the 100.

Just goes to show you, you never know what someone will show up with.

 

[CAPTAINMIKESSII]

I run 2 dive boats in hawaii and Ive got a continuous channel recessed about 3 inches below the bench with 1/3 scalloped pieces of 8" pvc and a scalloped rest at about 2/3 height of an al80 with bungee to secure the top. This allows people to easily set doubles 63's 80's 100's steels with boots all without any change or modification.Ive attached a photo.

 

[Tortuga James]

Last weekend I had a group with doubles, so I just split the roll control arms and put them in the rack unattached. Then I used heavy duty cable ties to attach a SS 1.5" ring to one arm and a piece of shock cord to the other with a brass clip. We set the doubles in, pushed the arms against each tank and then secured it with the shock cord. It worked well.

I have been frustrated adjusting my roll control racks every day for different size tanks. I thought the same set up would work with the singles. It didn't. So I reconnected the arms of the roll control holders at a really wide setting. Then we set the rig in, attach the shock cord around the outside and then add air to the bladder to snug the fit. That worked great and now we don't have to adjust them. A minor victory against the daily dive boat frustrations.

 

[Dr Dive]

Sorry for not posting pictures previously. I will be on the boat tomorrow and will try to take some. I use roll control. The only modification is to set them for AL80ish width and to add bungee to the arms. Drill a hole in each arm, thread the bungee and knot underneath. If you have an AL80, just drop the arms. If you have a larger, or odd size tanks, just raise the arms (provides lateral stability), set the tank in and pull the bungee over the valve. Works in heavy seas and rough conditions. We use the DAN number board to keep track of tanks and second tanks for each divers. Works for us. More to follow.
Capt. Jim