The Port of Rotterdam Authority contracted VSF to construct a total of three new moorings as replacement of buoy berths and dolphin configurations in the Caland Canal. The new moorings are suitable for the transhipment of goods from one sea-going vessel to another without having to be moored alongside quays or jetties and without the oil or other bulk products first having to be taken on land for interim storage and then transferred to larger or smaller vessels for further distribution.
The installation of all configurations and the replacement of the buoy berths with piles are part of an investment programme on the part of the Port Authority to further modernise and make use as intensive as possible of the existing port area. Replacing buoys with piles also promotes safety. The Port Authority is investing a total of some €32 million in installing pole configurations and replacing buoy berths. For more information on this programme, see the Rotterdam Port Authority website.
In the former situation, the moorings were created with seabed piles, anchorchains and mooring buoys. The major disadvantage of this way of mooring is that the moored vessels move back-and-forth in the busy Caland Canal as a result of currents, wind strength and wind direction at the mooring. Additionally, the risk of breaking loose in strong wind is greater than with the fixed mooring facilities, as with the dolphins that are now being used.
Due to the requirement in the contract that the mooring capacity should be upheld during the construction phase, mooring 79B was first constructed, after which it was possible to remove the mooring buoys from the old moorings 82 and 83 and install the new piles for these moorings.
Mooring 79B is suitable for vessels of a length of up to 160 m and moorings 82 and 83 for the biggest vessels: the ULCC (Ultra Large Crude Carriers) with a maximum length of 380 m and a maximum width of 68 m. The available width for mooring in the Caland Canal is 100 m, making it possible to also moor a 32-m-wide vessel (Panamax type) next to these giants for the transhipment of goods. To make the moorings suitable for these vessels, both the slope and the existing canalbed were dredged. The water depth is now more than 24 m at tide, sufficient for safe loading, after which these big vessels can sail out to sea at high tide.
Due to the location of the piles in the slope of the embankment of the Caland Canal, while the piles were being installed there was extensive monitoring by means of piezometers and water-accelerometers in the slope of the spit next to the Caland Canal. This monitoring enabled management of the possible risk of the slope shifting as a result of the vibration and pile driving energy.
Once the piles were driven, the pile heads, manufactured in our own workshop, were fitted. Due to the position of the welding seam below low water level at -0.5m NAP, welding boxes were used. After completing the welding and preservation work, the welding boxes could be dismantled and the piles further fitted with fenders, stairs, gratings, quick release hooks and the autonomous powersupply.
Within the framework of "a sustainable port", all 31 piles and piles heads were fitted with an autonomous power supply for driving the capstans of the quick release hooks, the nautical lighting and the work lighting for the boatsmen.
In anticipation of the dredging, the sheet pile walls for launching and mooring and tide compensators were drawn and repositioned. The sheet pile walls for launching and mooring serve for landing oil booms that are sailed out around the ships in the event of oil spills to limit the contamination of the surface water. The dredging and coastal and embankment work was executed by Boskalis, using grabdredgers with split barges as hoppers. The dredged materials were taken to various locations in the port and at sea.
What is unusual about the new moorings is the use of autonomous power supply. Instead of the usual electricity cables for supplying the lighting and the capstans of the quick release hooks, solar panels and batteries have been used. Apart from the saving in CO2 emmissions for the power supply, there are no longer any obstacles on the seabed between the piles and the shore. These cables sometimes snap during maintenance work, or during the mooring of vessels, which can compromise the availability and safety of the mooring. Each mooring and breasting dolphin is equipped with its own power supply by means of solar panels and batteries. The power supply and the capstans are ATEX certified, so they can be used at locations where there is a risk of inflammable vapours.
The majority of the work was carried out with VSF's own equipment or that of our sister companies.
The piles, for example, were put in place with Stemat's cranevessel Dina-M, with the piles first being vibrated with an ICE 36 Rf vibrator hammer and then driven with an IHC Hydrohammer type S280. To prevent damage to the coating, the sleeve of the hammer was specially prepared. Various in-house pontoons carrying our own Sennebogen and Liebherr crawler cranes were used for the assembly work. Our working vessel Geertruida M was used for the welding.