- The latest offshore cranes are provided with a
CT = Constant Tension system.
PMC = Passive motion Compensator .
AHC = Active Heave Compensator
- All has been descripted by John Stouten in his leaflet 1988.
- However when you have NO AHC than you have a useless product ,herewith we will submit some more information by showing a very brief silhouettes comprising :
I) - CT mode : Ship with crane stays still and floating load goes Up & Down, with a CT system the winch wire will under tension following the floating object ( Buoy ),at the highest point the crane operator can raise the Load .
II) - PMC mode: The Ship with crane are going Up and Down , however the load on the platform stays still , this CD procedure is called PMC.
III) - AHC mode: Cranes acting in the subsea industry are mainly provided with an Active Heave Compensator ,The ship goes Up /Down (movements measured by a Tautwire system) and the load located under water must be hanging Still .( =/- 3%).
The Up & Down stroke of the crane-ship can be compensated by a so called Jigger-winch ,most assisted by Stored Energy (Accumulator bank ).
- An AHC system for cranes with a large SWL has about the same price as the crane price , STOUCO has made a few alternatives consisting NO complicated electronics and high educated engineers onboard with many droppings and facing problems.
- WE TRANSFER THE WINCH - please see the sketches IV - V.
The sketch VI show a new generation Pulling /Hoist winches with 3000 mtr steel wire rope Line pull up to 600 T and heave stroke up to 12 mtr.
- Total winch package ( w 250T) situated below the deck of the ship