Aquatech Black Sea hydropneumatic gun

Jegwan said:

Thanks for your answer and info. Both of the pictured types of spear tail valves in brass has shank OD 5.8mm.

I suppose that using the spear tail piston with the sliding "O" ring will mean that water will leak into the barrel trough the drilled vent hole when shooting the gun.

Click to expand...

No it will not as water pressure will push the "O" ring right up against the front shoulder of the spear tail groove and drive the spear from the gun in milliseconds, so no water can get around the spear tail. When you initially flood the gun you use the hydropump first without any spear in the gun, then you put the spear in the gun and pump it in the barrel a few times. This opens and closes the trigger valve or releasing valve and removes the last air bubble from the hydraulic locking chamber. The spear tail valve lets that air bubble out and water in. The alternative using only the hydropump is to do a preliminary dummy shot to eliminate any air bubbles inside the hydraulic locking chamber. Flooding is always done with the line release lever swung open to keep the trigger operated pilot valve open.

Diagram is attached showing the internals of the gun.

I am really glad to hear that you got the gun going and into action at last, especially after the situation where the previous owner did not have much luck with it. The guns as you now know are simple to use, but are very different from the usual pneumatic speargun. Watching the shooting line bridge the distance to the target virtually instantaneously with only a small clinking noise emanating from inside the gun (the biasing spring rebounding) certainly makes them exciting guns to use. I can understand the local divers being impressed with it. I sent Sergiy Kravchenko a Christmas greeting as I do each year, but I received no reply this year, so I don't know what the current situation is with "Aquatech". Provided you wash your gun out after use and let it dry out if not using it for a long period (more than a week) then you should have no problems with it.

I found some white plastic vinyl caps that I use to cover the exposed rear end "O" rings and screw threads when the guns are in storage, maybe you could find something similar to cover your barrel when the rear handle is removed. It keeps the rear entrance area clean and you can then store the handle/rear caps in a separate location for security purposes.