When the grab is closed and filled with material, it can be opened by putting it down on the floor or hopper. At that moment there are no forces acting on the closing mechanism and it will uncouple. After lifting the grab again, it will open and the material is unloaded.
The advantage of touch-and-go grabs is that they are extremely reliable and very economical. The opening mechanism is 100% mechanical and therefore very dependable. In the exceptional situation that the system would not work properly, it is very easy to repair.
Besides the above described advantages, there are also situations that other single rope grabs can be more suitable. The two most important situations are described hereafter.
In case of loading into a hopper, the complete load (grab + material) will be placed on the hopper. In case your hoppers aren’t strong strong enough to withstand these forces, it can be damaged. In this case a single rope grab with mid-air opening (manual or remote control) are more suitable.
The grabs are less suitable for loading vessels. Because the only way to open the grab is to put it down, the grab has to be lowered completely to the ship’s bottom before it can be opened. This results in a long cycle time which slows down the operation. Therefore a grab with mid-air opening (manual or remote control) is the best solution for loading vessels.
