A crane includes a boom and a derricking mechanism, wherein: the derricking mechanism includes a linking device connecting one end of a guy line to a distal end of the boom; the linking device includes a joint connected to one end of the guy line, and a support device provided on the distal end to support the joint so as to locate the joint at a position away from the back surface and opposite to the ventral surface; and the support device includes a holding member which holds the joint, the holding member allowing the position of the joint to be selectively changed to a plurality of different positions in a first direction perpendicularly intersecting an axis of the boom and a rotary axis of the boom.

A portable crane formed of composite members. A composite mast is coupled to a composite boom. A boom end housing removably couples at a top of the mast and includes an enclosure. A first end of the boom couples within the boom end housing. A boom pivot couples to the boom end housing and couples the boom to the mast. An angle adjuster releasably secures the boom at a desired angle relative to the mast. In implementations an end cap is included at a second end of the boom, coupled to a sheave with a pin, the end cap covering a terminal end of a second end of the boom and extending along both sides of a slot in an upper surface of the second end and along a portion of a first side of the second end and along a portion of a second side of the second end.

A portable crane formed of composite members. A composite mast is coupled to a composite boom. A boom end housing removably couples at a top of the mast and includes an enclosure. A first end of the boom couples within the boom end housing. A boom pivot couples to the boom end housing and couples the boom to the mast. An angle adjuster releasably secures the boom at a desired angle relative to the mast. In implementations an end cap is included at a second end of the boom, coupled to a sheave with a pin, the end cap covering a terminal end of a second end of the boom and extending along both sides of a slot in an upper surface of the second end and along a portion of a first side of the second end and along a portion of a second side of the second end.

A plant for the construction, preferably cantilevered, of engineering works which includes a main structure configured to rest, during use, on permanent structures (P) of the engineering work.

A plant for the construction, preferably cantilevered, of engineering works which includes a main structure configured to rest, during use, on permanent structures (P) of the engineering work.