Grenades are highly destructive to both people and objects, including vehicles — in most GTA games, conventional vehicles can be destroyed with a single grenade, and people will almost always be killed if within the blast radius. Grenades are ideal for taking out enemies hiding behind cover, and for scattering tight-knit groups of foes.
Grenades can, of course, be just as dangerous to the player as to enemies, and must be deployed carefully to avoid the grenade bouncing back to the player. In Grand Theft Auto IV, the player can drop a live grenade to the ground, but must run for cover before it detonates. One can also 'cook' a grenade (hold onto it while it counts down) for a short time before throwing it. It begins beeping if it is held for too long, and if not thrown, will explode in the player's hands. In Grand Theft Auto IV, grenades are in fact much more lethal to the player than to enemies -- unless a grenade explodes very close to an enemy, they will likely survive, despite being thrown by the explosion.
In GTA IV, grenades can be dropped while driving, and are more effective for in-car use than Molotovs, due to their far superior radius of effect, however the player must take care to remain on the move while using grenades — the player's own car can easily be caught in the explosion if it does not move on immediately.
Portland Docks, Portland- On the back of the black boat to the left of the blue freighter that you use on the mission "The Portland Chainsaw Masquerade" Opposite side of ramp. Hidden package near.
Steinway - Can be found in the fourth gated yard in an alley between Tinconderoga Ave and Trenton Ave.
Meadows Park - Can be found underneath the large steel globe in the larger fountain.
Francis International Airport - Can be found on the west end of the boat dock south of the aviation fuel storage facility to the southwest of the airport.