Releasable universal overshot

The releasable universal overshot is a very suitable tool for externally engaging, packing off and pulling out the fish. The overshot has three main parts: the top sub, body and guide. It may be assembled either with a spiral graple (if the fish diameter is near maximum size for the particular overshot) or with a basket grapple (if the fish diameter is considerably below the maximum catch size). According to this different type and size of control ring and top seal belong to the internal parts. As the top of the fish is reached, slowly rotate the overshot (with the fishing string) to the right and lower them into the fish gradually. Stop with the rotation, release any right-hand torque in the fishing string and pull up the fish by elevating the fishing string. If the fish is caught, start the circulating pump and maintain a heavy upward strain while the fluid is forced through the fish. Bump down the weight of fishing string heavily against the overshot, then rotate to the right and slowly elevate the fishing string. Rotation will prevent grapple from biting while overshot is removed from fish. The releasable universal overshot requires right-hand rotation only, both during engaging and releasing operation, this fact eliminates the danger of an unscrewing.

Assembly procedure:
1. Assemble top sub to body.
2. Thread the suitable size (spiral of basket) grapple into left-hand helix into the body until helix in the body exposed below grapple and slot in grapple lined up with slot in body and slide grapple control ring into body, tang end first, until the tang engages the slot in both the barrel the grapple (or slides beside tang on grapple ring using a spiral grapple).
3. Assemble the guide to body.
4. Top seal (may be used with the spiral grapple) can be placed in body above the helically spiral section, before threading the spiral grapple.
5. Basket control ring has a replaceable inner seal and replaceable outer seal for each size of fish and for each type of basket control ring.