These figures often reflect traffic that would ‘drive on or off a ship’ – one example is ferry traffic. Last year, TTS Port Equipment AB from Sweden, delivered a new linkspan to the Stena Line terminal in Hoek van Holland and one in Harwich. These new linkspans were in anticipation of the arrival of the new Super Ferry from Stena Line, which is now in service on the English Channel between Hoek van Holland and Harwich. But indications show that the global economic downturn has ‘spoiled’ what was once a buoyant but competitive market. According to Heli Malkavaara, Communications Manager at Cargotec, last year was a dire year for linkspans. “Most projects where we had an interest were postponed severely or cancelled,” said Malkavaara. “We can’t tell however if it is a direct cause of the downturn. Apart from funding, environmental consents have a large impact on the eventual realisation of port projects.” There are indications that economies are picking up again and it seems that postponed projects are attracting renewed attention with Cargotec recently receiving an order to widen and convert a linkspan in Scotland to fit to a new vessel.
Market
Although some deliveries were made in 2010 most of these were orders from 2009. In March 2010, TTS Port Equipment delivered a new linkspan to the Port of Kiel, Germany. At the Bollhörnkai berth Stena Line was updating and rebuilding their ferry terminal for their Gothenburg route. Part of the improvements was to replace the existing concrete slope with the installation of an adjustable main deck linkspan. TTS supplied a 26m wide linkspan designed to fit several vessels. The new linkspan was also equipped with noise reducing features and designed as a mechanical supported type, hinged on a bank seat concrete foundation. At the seaward end the linkspan is adjustable to fit different vessel draughts and water levels, and can manoeuvred by means of hydraulic cylinders. It is also capable of being secured at a series of fixed positions prior to the vessel’s arrival. The berthed vessel’s ramp will be lowered until it rests on the linkspan in free-floating mode. TTS Port Equipment has been working hard to respond to a market that is perhaps coming slowly out of the doldrums and in November 2010 it received an order for a new purpose-built mechanical linkspan for catamaran traffic from the Port of Ystad, Sweden. The linkspan will facilitate the Borholmstrafikken ferry company’s catamaran traffic between Ystad and Ronne on the island of Bornholm. To accommodate the higher freeboard common to catamarans, the linkspan will be set at a higher level than for other traffic. The catamaran Villum Clausen will be using the new linkspan together with a new vessel ordered from Austal Yard in Australia. Having delivered a similar installation to Ystad in 2009, TTS is building the new linkspan on the same principle of hydraulic cylinder operation. “We are pleased to have received this second order and we look forward to continued collaboration with the contractor Svevia and the Port of Ystad,” said Hakan Jonsson, Vice President of Sales at TTS Port Equipment.
Additional
The manufacturers we spoke to also incorporate or supply additional equipment for their linkspans. This equipment could range from mooring systems to fenders and these could be added to the design of the linkspan. TTS Port Equipment for example received an order in 2009 from Copenhagen Malmo Port, Sweden for the design and installation of two double-tier linkspans for the port, and was given the go-ahead to supply a semi-automatic mooring system. The linkspans were installed late 2010 with the mooring system delivered at the same time. The rope-type semi-automatic mooring system has been installed in the new port’s north harbour and is designed to buffer the transverse forces from dedicated vessels. Each vessel has been fitted with a compatible bollard installed into the ship’s side. The system comprises the auto-mooring rig, including a hydraulic cylinder and a hydraulic power pack housed in a cabinet on the quay. Quayside personnel operate the equipment by push buttons and by manually directing the self-tensioning rope around the vessel’s fitted bollard. Safety features include an alarm system designed to alert personnel of significant changes in tension or of system failure. Jonsson also points out that last year TTS received orders to improve the Stena Line berths at Gothenburg’s Majnabbe terminal. The company designed and installed an adjustable wedge system. The wedge, with a width of 8m, connects the berthed vessel’s ramp to the main deck and is installed on top of the existing concrete ramp. Hinged at the bankseat side, the wedge will feature container corner fittings recessed in its top plate structure for convenient manoeuvring by a reachstacker. When the wedge is to be placed on top of the concrete ramp, the reachstacker will lower the wedge to its deployed position. The wedge will be adjustable to different levels at its forward end to enhance transition angles and traffic flow. The adjustable wedge is designed with a special low noise feature that makes it especially environmentally friendly. The surface of the wedge under the vessel flaps are covered with special noise-absorbing panels, as the underside of the wedge flaps towards the bank seat. For the same terminal TTS also received a contract for a semi-automatic mooring system to serve two vessels at the new dolphin berth. The system facilitates m
ooring of the 240m long vessel berthing the quay, will greatly simplify the mooring of vessels Stena Brittanica and Stena Hollandica. Hydraulic cylinders are connected to a sliding bollard in a steel structure on the quay while, onboard the vessels, three bollards are recessed into the side of the vessels, each positioned at a transverse angle to the vessel to achieve the required mooring force. A spring mooring device designed to handle the forces with automatic release function will also be used during operation of the vessel in the berth. Last year, a similar contract was awarded by Stena Line (UK) for their operations in Stranraer, Scotland. Stena is moving its operations and ferry services from the present location in Stranraer to a new, state-of-the-art port facility ten kilometers north of the town. The contract included the design and build of the entire ship to shore interface for the port, including linkspans, stop fenders, auto-moorings and an elevated walkway. The adjustable upper- and lower-deck linkspans were designed for use by a variety of RoPax vessels using a stern approach, with the option of bow approach given within the flexible solution. The three-lane lower-deck linkspan have an overall length of 24m while the upper-deck linkspan features a 25m long concrete wedge, together with steel fixed access ramps and movable ramps. An adjustable ramp will be elevated by means of hydraulic cylinders mounted onto the lower-deck linkspan. A lifting ramp is hinged to the adjustable ramp and rest on the berthed vessel. The upper deck linkspan offers the possibility of movement along the ship to maximise the port’s flexibility in vessel accommodation. A stop and positioning fender has been installed onto the bankseat and supported by the lower-deck linkspan. The fender is adjustable for different vessel types and acts as a guide to fix the vessel’s position. An automatic mooring system designed for RoPax vessels is also installed along the pier. This comprises auto-mooring devices, each consisting of a vertical moving unit and two hydraulic cylinders to create the mooring force. TTS also designed and built an elevated passenger walkway, connecting the ships to the terminal area.
Safety
According to Cargotec’s Malkavaara, fenders can cause a major issue in the design of a linkspan. Therefore cooperation with fender suppliers is a must. “But they have a product, but not always the experience in the application on a linkspan,” said Malkavaara. “We are confident in our own experience, and focus on the use of a few standard types of fenders which are easy attainable from any supplier.” To address this important issue, Clas Hedelin, Sales Manager, Land & Port Systems, Cargotec Sweden AB explains. “Over time ship impact on port structures is unavoidable. The No 1 mandatory risk assessment question prior to every new port development must be: What if a 20,000-tonnes vessel runs into the quay at a speed of one knot? You do not need to be an engineer to realise that the damage will be severe. That piece of ‘quay’ may well be a linkspan, so careful steps in design are required to protect its lifetime integrity. A key to a successful linkspan installation is a safe and functional design with minimum downtime. A berth with a linkspan should be safe against accidental impact from an approaching vessel. It may even have to survive an abnormal impact without collapsing. The use of rubber fenders in the design is an important way of gaining elasticity and maintaining functionality in the harsh environment a RoRo berth has to perform in.
To fulfil the requirements dual-function fenders need to be fitted to the linkspan. Firstly, front edge fenders, which are often belts of simpler fenders, are used to absorb light impacts. Secondly, fenders to withstand major impacts, consisting of larger fender types, are installed between the linkpan and the shoreside abutments.” Hedelin explains that these integrated solutions are calculated to withstand, in abnormal conditions, the largest ferry that can use the berth. Furthermore the interface between the linkspan structure and shoreside portals, abutments or offshore piles raises the need for intermediate use of fender material to restrain the overall system. To minimise turnaround time in port some berths are designed for direct impact from each and every approaching ferry to allow it to dock. Examples are some English Channel, Canadian and Scandinavian shuttle services and many high speed ferry services. This puts high demands on the berth designs, which pay off in turnaround times down to – hardly imaginable – ten to fifteen minutes. In essence the solution is the clever application of a few standard types of fenders which are easily procured from any fender supplier. According to Hedelin, Cargotec’s success stems from its own in-house expertise, experience and know-how in developing the integrated applications for linkspans, since the approach by most fender suppliers tends to be aligned towards traditional fender use in ports and often lacks the understanding of the needs of a linkspan installation. A relatively recent application of rubber or fender plastics is to reduce noise during operation. A Ro-ro berth is very noisy and reasons to reduce the noise include providing a comfortable working environment for crews and stevedores, but also limiting the negative impact on people who live nearby. Trailers and lashing equipment both represent big individual sources of noise, but contact surfaces between vessel and linkspan ramps can gain much benefit from attaching rubber or sandwich compound preventing the noise from spreading throughout the structures. This is a compromise between function and lifetime of the material and Cargotec is currently expending efforts in developing durable high performance solutions to this problem says Hedelin.