An impact jar apparatus including a dynamic portion connectable to an upper tool string portion, a static portion connectable to a lower tool string portion, and a hydraulic manifold, an activation indicator, a relatch assist, and/or a shock absorber. The hydraulic manifold fluidly communicates with an annulus between the dynamic and static portions. The hydraulic manifold adjusts a delay between application of a trigger tension and consequent activation of the impact jar apparatus. The activation indicator, including a wire coil in the static portion and magnets carried by the dynamic portion, generates a magnetic field whereby a voltage pulse is generated in the wire coil in response to the magnetic field passing the wire coil upon activation of the impact jar apparatus. The relatch assist urges the dynamic and static portions toward a latched position. The shock absorber absorbs axial shock generated by activation of the impact jar apparatus.

An impact jar apparatus including a dynamic portion connectable to an upper tool string portion, a static portion connectable to a lower tool string portion, and a hydraulic manifold, an activation indicator, a relatch assist, and/or a shock absorber. The hydraulic manifold fluidly communicates with an annulus between the dynamic and static portions. The hydraulic manifold adjusts a delay between application of a trigger tension and consequent activation of the impact jar apparatus. The activation indicator, including a wire coil in the static portion and magnets carried by the dynamic portion, generates a magnetic field whereby a voltage pulse is generated in the wire coil in response to the magnetic field passing the wire coil upon activation of the impact jar apparatus. The relatch assist urges the dynamic and static portions toward a latched position. The shock absorber absorbs axial shock generated by activation of the impact jar apparatus.