From a single hook to subsea ROV hook, from hand hammering to hammering by hydraulic or pneumatic force.
As the human being evolution and history, crane hooks have been also developed and sophisticated in connection with the lifting & mooring operations complexity.
In the past, hooks were made of unique single grade, carbon steel, and, even the working load was higher, hook should be larger with no material neither design modification. Hence manufacturers limitation was based on forging capacity only.
During these times heating process was ancestor, based on fuel & coal mainly, and forging process much more ancestor by hand hammering and bending.
When steel grades started developing (first in the rope industry and consequently in connecting components as hooks) alloy steels permitted to increase working load not forcing to increase size/weight necessarily. Hence the right combination of steel grade, heat treatment and design (weight/size) became the key to increase the increasing heavy lifting industry.
During these times heating process was already clean & controlled by gas and forging capabilities heavy enough for die hammering by hydraulic or pneumatic force.
Nowadays, loads can be moved or handled by vertical or horizontal way in any grade, lifting or mooring, hence lateral and transverse forces move the classical gravity center, becoming the key to design critical sections with sufficient mechanical properties but competitive enough to be safe, comfortable, low maintenance and cheap.
SoPHistication comes true in the hook industry and new European Standard EN13001-3.5 will instruct the whole industry into this sophistication, being first designer and then manufacturer.