Lifting Cranes

have you tried any search engines such as google to find definitions?

what do you understand about boom's, cranes?

A "boom" is the sound of an explosion.

A" Luffing boom" is the sound made when someone named Luffing explodes.

A "jib" is part of a sailing boat.

a "Luffing jib" is part of a sailing boat owned by someone called "Luffing"

From the COED

luff chiefly Sailing

n noun the edge of a fore-and-aft sail next to the mast or stay.

n verb steer (a yacht) nearer the wind. Øobstruct (an opponent in yacht racing) by sailing closer to the wind.

ORIGIN

Middle English: from Old French lof, probably from Low German

In relation to a crane.

A jib crane has a fixed jib where as a luffing jib is able to raise or lower to alter the radius of a lift.