Safe Crane Operations

• Accurate wave input for the Safe Load Indicator
• Less Waiting On Weather
• Video of blind zones on deck
• Better timing and control of heavy lift
• Optimised planning of back load
• Enhanced personal safety
• Easy installation, suitable for retrofitting

BIG DIFFERENCE

DMM gives benefits in both ends of the weather window compared
to the conventional methode. When the sea builds up, you can continue longer and when it calms down you can start earlier

VIDEO AND WAVES
– THE FULL PICTURE

Video from the supply vessel deck camera gives the Crane Operator an additional view angle which covers blind zones on deck and vessel motions as seen from the navigation bridge.
Real time wave data from the selected deck area may be displayed beside the video display.
This video may be recorded on board the supply vessel.

TIMING OF THE HEAVE

In different weather conditions, it is difficult for the Crane Operator to determine how the vessel deck area is moving, making it difficult to time the heave. The real time wave curve from the selected deck area is displayed in the DMM crane and makes it easier for the Crane Operator to time the heave.

AVOID THE UNCERTAINTY FACTOR

There are a number of ‘uncertain factors’ connected with today’s simplified method: The offshore crane standard EN 13852-1, Annex B Chapter B1 and Table B.1 describes the simplified relation between the (oceanographic) Significant Wave Height and the vertical velocity (m/s) of the load supporting deck.
The vertical velocity of the load’s supporting deck VD is in this standard is solely dependent of the significant wave height H1/3, which measured by a nearby wave rider buoy or wave radar.

This means that no further consideration is taken to the following:

• The variation in wave type and period
• The variation in downward velocity at different deck positions
• The variation in shape, stability and loading condition of the vessel
• The variation in direction of the waves in relation to the vessel heading
• The variation in sea state, from the position where the wave height is measured to the position of the vessel (close to a platform)

All the above mentioned ‘uncertain factors’ are eradicated by using our revolutionary DMM. Now, the vessel officer and Crane Operator can make decisions based on facts!

INCREASE THE AVAILABILITY OF
SEA LIFT

The current H1/3 Sea Lift method is normally too conservative.
DMM (H1/3 Eff.) has proven its potential in the North Sea to increase the availability of lifting operations, compared to use of the H1/3 method. This benefits all types of supply vessels.
Waiting On Weather time may be reduced up to 50%, which benefits the supply logistic and reduces the fuel consumption.

DMM ASHORE FOR BETTER PLANNING OF BACK LOAD

Images and data from the cargo deck can be E-mailed ashore to the logistic department for better planning of back load.

It is important to note that back load is difficult to make plans for. Containers, risers, etc. may be located quite different than first planned along the supply vessels’ route.

With updated deck images and DMM overlay ashore, it is much easier for the shore based logistic department to make plans for the back load.

OPTIMAL VESSEL HEADING

The heading has influence on vessel motion since a slight change in degrees for vessel heading may considerably change the deck motion.

DMM makes it easy for the Dynamic Positioning Operator to find the optimal heading of the vessel, to ensure minimum heave motion at the actual deck area where the Load/Cargo is located.

HEAVY LIFT AND BACK-CATCHING

During heavy lift operation, the risk is bigger and margins for error are much smaller.
With the load moving slowly upwards, there is a significant risk that the deck back-catches resulting in slack crane wire. This will almost definitely result in a powerful downward jerk when the vessel moves downwards again. Situations like these may exceed the crane’s safe load limit.

With DMM, we make your decision to carry out or delay the heavy lift, much easier!

PERSONNEL SAFETY
– WORK ON DECK

Personnel safety is undoubtedly a priority.
When working on deck, the risk for injuries and falling over board increases with the ship’s motions and waves.
Combined with Captain’s overall assessment, DMM may be used to set operational limits for working on deck.

LAUNCH AND RECOVERY OF EQUIPMENT OVER BOARD

Most marine equipment and operations has got wave height limits to prevent damage or loss of equipment during launch, operation and recovery.
When the Sea State increases or decreases, the DMM can be used as a tool to decide whether to start, delay or stop the operation.