The grappler system of a NX-class starship.
The grappler was a metal shaft with claws on the end that could be launched by a starship to grap objects in space. The grapplers utilized a magnetic lock device to attach to objects.
The NX class starships of the Earth Starfleet possessed two grapplers. However, their use was eventually superseded by the development of the superior tractor beam. (Star Trek: Enterprise)
Enterprise grapples a D5 class as an improvised battle tactic.
Shortly after its launch in 2151, the NX-01 Enterprise used the grappler to capture a Suliban cell ship, which was evacuated by its lone Suliban occupant and brought aboard Enterprise. The ship was then used by Enterprise crew to infiltrate the Suliban helix. (ENT: "Broken Bow")
Later that same year, Enterprise Captain Archer attempted to use his ship's grappler to retrieve Shuttlepod 1, which had fallen into a chasm within a large comet. Although only one of the two grappler claws latched onto the shuttlepod, it proved sufficient enough to reel the craft back to the ship. However, the eisilium in the comet's composition began to disrupt the grappler's magnetic lock, and the Enterprise was forced to lower and release the pod before the connection broke. Fortunately, a Vulcan ship was nereby to offer assistance, and following a reluctant request by Captain Archer, the Vulcans were able to retrieve the shuttlepod using their vessel's tractor beam. (ENT: "Breaking the Ice")
Also in 2151, Enterprise again used the grappler to retrieve its own shuttlepod after it had been stolen by a female Klingon. Three Enterprise crewmembers had used the pod to board a Raptor-class scout vessel, the IKS Somraw, which was sinking into the atmosphere of a gas giant. The ship's engineer, Bu'kaH, hijacked the pod, stranding the three crewmen aboard her endangered ship. She then attempted to contact her people to falsely blame Enterprise for the attack on her ship which landed the inside the gas giant, but the pod was captured via the Enterprise's grapplers and Bu'kaH was brought aboard. (ENT: "Sleeping Dogs")
- The Vidiian's made use of a similar technology.