During the preparation of the tender offer the contractor already has an idea of the working method for the project and the availability of dredging equipment and personnel. When the contract is awarded the contractor starts planning the operation in detail and mobilisation will usually start as soon as possible.
Proper project management implicates accurate planning of the project execution, with the appointment of sufficient staff and reservation of the required equipment and auxiliaries. Office staff, the area manager, the project manager, the site manager and surveyors will all have to contribute their knowledge and experience to the preparation of the working method and planning of the operation, so that the project can be executed successfully.
Working plan and time schedule
Normally the contractor has to present a working plan with time schedule to the employer or his engineer. The working plan has to contain a description of the method of operation and the contractors project organisation.
Special attention can be given to the system of dredging and discharge, including:
- Working hours per day and per week
- In hopper dredging, the time for loading, sailing and discharging for the various sections in the dredging area, and the loading capacity for the various types of soil to be dredged
- System of discharge, via hopper doors or by means of a shore connection system
- Floating or submerged pipelines, land pipelines, spur dikes, water outlet and settlement markers.
Knowing the specifications of the equipment and the soil, it is possible to make estimations of the hourly dredging production in the different sections or layers of soil. From the total volumes and the available working hours per week, the overall number of operational weeks can be deduced.
The time schedule has to include:
- Mobilisation, arrival and site preparations
- Operations, specified in different sections
- Maintenance and completion
Before equipment is shipped, it is worthwhile to investigate the availability in the project area. Hiring equipment locally can save time and money. In most countries, no real dredging equipment can be found, but additional equipment like pontoons and bulldozers can sometimes be hired.
Since all dredging activities are based on surveys, the survey plant and staff are very important. Sending the surveyors out before the total equipment arrives on site, helps maintain the momentum. Many dredging projects start with confusion on benchmarks, coordinates and tide gauges. It will be very useful to check the data together with the local surveyors and make sure that operational surveys can start directly on arrival of the equipment.
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Shipping of equipment
If there is no certainty about the availability of local equipment, the contractor will bring his own equipment. Hopper dredgers are extremely mobile. Therefore, they can easily be sent from one part of the world to another and it is common practice to transport the additional equipment on board of the hopper dredgers as much as possible. Cutter suction dredgers are usually not equipped to sail themselves, so they have to be shipped. Most standardised cutter suction dredgers are dismountable for transport by road, rail or sea. Heavy stationary dredgers are transported by semi-submersible barges. Mobilisation ends at the moment that the complete equipment and auxiliaries are ready to use and production can start.
Click here to read more about the execution and monitoring of the project.