The present invention provides an improved shackle having particular utility in underwater salvage operations. The present invention discloses a shackle that has a generally U shaped body that is comprised of a bow portion and first and second spaced apart arms. Each arm has an end portion with an opening for receiving a shackle pin. The shackle pin is sized and shaped to simultaneously fit through the shackle pin openings, and end portion of the pin having external pin threads. A nut provides an internally threaded opening for engaging external threads of a shackle pin. The nut is rotatably mounted to a second end portion of the shackle body. The external pin threads of the shackle pin and the internal threads of the nut are engaged when the pin is connected to the nut by rotating the nut. The pin does not rotate relative to the shackle body, due to an elongated groove in the pin that travels on a key portion of the shackle body that is in one of the openings.