Ditchable scuba tank weight device
Kind Code:

A ditchable trim weighting device for scuba tanks, comprised of a length of curved tubing made of elastic material (preferably rubber) filled with shot or a combination of lighter material, sealed flat on the ends which are threaded as straps to the male and female elements of a quick-release buckle (preferably side-release) providing a stretched, snug grip when fastened around a standard diameter scuba tank.

King, William Derry (Missoula, MT, US)
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Primary Class:
Other Classes:
405/185, 441/88, 114/315
International Classes:
B63C11/30; (IPC1-7): B63C11/02; B63C9/08; B63C11/00
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I claim:

1. A ditchable scuba tank weight device comprised of a length of appropriately sized curved tubing, made of elastic material such as rubber, filled with divided weight (such as lead shot or a combination of differently weighted pellets) between flattened and sealed ends, said flattened ends threaded as straps onto a quick-release buckle (preferably side-release), allowing a stretched, shape conforming grip when buckled around a standard diameter scuba tank.

2. According to claim 1, a shot-filled rubber tube, sealed flat on both ends.

3. According to claim 1, the integration of the functions of said tubing as weight and strap by said process of fabrication.

4. According to claim 1, the conversion of said tube ends to flat straps as the means of attachment to said quick-release buckle elements.

5. According to claim 1, the variation of the weight of the device, while preserving the embodiment of the invention, by means of employing a combination of different weight materials in the weight fill component.

6. According to claim 1, an elastic, stretchable weight comprised of a length of said tubing filled with divided weight, such as lead shot and sealed flat on both ends.

7. According to claim 1, the use of said flattened tubing ends as straps for the purpose of attaching said buckle elements.

8. According to claim 1, the use of curved rubber tubing to ensure greater contact and grip and easier application of the device, than if straight tubing were employed.

9. According to claim 1, the cushioning effect, as a result of the embodiment of the invention, as a protective bumper and anti-roll device.



[0001] The original standard for scuba tanks was steel with capacities of 50 and 70 cubic feet of compressed air or mixed gasses. These tanks often developed corrosion problems, prompting the introduction of aluminum tanks and the phasing out of the older steel variety. The aluminum tanks are more problem free and are higher capacity (80 cubic feet) at 3,000 pounds of pressure.

[0002] With the increased use of lighter aluminum tanks in scuba diving came the problem of increased buoyancy caused by the depletion of air as it is consumed during a dive. Heavier, lower capacity steel tanks have enough extra weight to offset most of the increased buoyancy caused by air consumption.

[0003] To solve the problem of increased buoyancy, more weight is required to attain residual negative buoyancy with one's Buoyancy Control vest empty and air tank depleted to the point where it is time to surface. The extra weight cannot be carried by most weight belts, so it is usually carried in the forward pockets of the Buoyancy Control vest. This creates an excessive forward weighting imbalance that is made worse as tank buoyancy increases with air consumption. This forces the diver to fight the resulting forward pressure to achieve proper trim or position in the water, especially at the end of a dive when fatigue can make the face-down pressure a safety problem. Weights added to the pockets of a vest are not easily removed in an emergency.

[0004] Several devices have been used as tank weights to remedy the problem of excess tank buoyancy.

[0005] Weighted pouches and lead weights attached in various ways to belts strapped to the tank have been employed (U.S. Pat. No. 4,455,718 to Finnern). The disadvantages of this type system are that they tend to slip out of position after the webbing becomes saturated with water and expands and the pouches and solid weights are bulky with the weight unevenly distributed. One device is comprised of a web strap harness which can hold one ore more individual cylindrical weights in bandolier fashion. This system is not removable in a dive emergency and is subject to slippage with water saturation as well. It is also more expensive than other systems. Pouches for weights are also made to be threaded onto the tank retaining band. since the tank band is what secures the tank to the diver, it cannot be removed during a dive and the fact that many tank band widths and configurations exist precludes their use with many tank bands. These are also bulky with uneven weight distribution.

[0006] Lead weights in a flat ring shape are made to be put in a boot which is fitted onto the bottom of the tank (U.S. Pat. No. 5,788,475 to Henderson). This method requires two lead rings to achieve the optimum ballast weight of about four pounds and the necessarily tight fit of the boot makes it extremely inconvenient to transfer from one tank to another, necessitating the purchase of weights for each tank the diver owns (usually two or more). As a result of this configuration, one cannot ditch the weight during a dive emergency and the extra weight stays with the tanks, making them more cumbersome to handle. Another system uses a special tank boot with weights fitted into it with a retainer which can be pulled to release the weights (U.S. Pat. No. 6,030,146 to Nicolen, et al.). This has the disadvantages that the system is not easily transferred from one tank to another and the ring pull used to release the weights may be accidentally snagged, dropping the weights unexpectedly.


[0007] This novel device provides a safer, more effective, easier to use trim weight system for attachment to a standard diameter scuba compressed air tank.

[0008] This invention incorporates several features which solve the problems posed by existing devices and systems designed as tank weighting to compensate for excess back buoyancy produced in aluminum tanks by the consumption of air during a dive.

[0009] With this device the “strap” and weighting functions are integrated by way of a curved stretchable tubing (such as rubber) filled with finely divided weight (such as lead shot) that is sealed flat on both ends to allow the attachment of a quick-release type buckle (preferably side-release).

[0010] This embodiment allows the device to be stretched enough to provide a snug, non-slip grip on any standard diameter scuba tank. The device is easily transferred from one tank to another and provides a low-profile distribution of the weight around the tank. The side release buckle prevents accidental release during a dive and provides for instant release in an emergency. The flat buckle and softness of the shot-filled tubing also allows it to function as a protective bumper and anti-roll device during transport.


[0011] FIG. 1 shows a perspective external view of the invention.

[0012] FIG. 2 shows a cross-section view of the shot filled tubing.

[0013] FIG. 3 shows a perspective view of a flattened and sealed tubing end.


[0014] The invention (FIG. 1) is a scuba tank trim weight device comprised of a shot-filled (FIG. 2) length of curved rubber tubing 11 with the ends (FIG. 3) sealed flat 12 to allow the female element 13 of a quick-release buckle to be attached to one end and the male element 14 of a quick-release buckle to be attached to the other end. This configuration, sized by tubing length and diameter to hold approximately four pounds (more or less) of shot 15, allows the device (FIG. 1) to be stretched around the tank to a snug fit with maximum contact and buckled.

[0015] Existing devices intended as tank ballast typically incorporate weighted pouches made of various materials, sewn or threaded onto buckled webbing. Lead bars and rings are also made to be attached to straps or inserted into a tank boot.

[0016] This novel device is assembled by cutting the curved rubber tubing 11 to the appropriate length (about 24 inches), sealing about 1¾ inches of one end (FIG. 3) flat 12 with adhesive (such as cyanoacrylate) and held with a clamp, then filling the tube with shot 15 using a metered dispenser. The shot 15 is then tamped tight in the remaining open end of the tubing to allow sealing the end 12 flat (FIG. 3) in the same manner as the other end. When the adhesive is set the clamps are removed and the sealed, flat ends 12 are threaded as straps onto each element of a quick-release type buckle 13,14.

[0017] The preferred embodiment of the invention utilizes rubber, lead shot and a side-release buckle 13,14. A lighter version can be made by substituting neutrally buoyant or lighter pellets in place of some of the shot 15.

[0018] The device is buckled onto a standard diameter scuba compressed air tank before a dive to provide counterweight to compensate for the weight of the air used during the dive, thereby counteracting the forward, face-down pressure produced by the increased buoyancy of the depleted tank, and ensuring an upright position in the water after surfacing from a dive.