On 14th February 2019 Damen Shipyards Group was awarded a contract by WSA Rhine-Koblenz (Waterways and Shipping Office) for a rather unusual form of vessel, a new diving bell ship. The modern, 21st century diving bell newbuild succeeds an existing vessel, the Carl Straat, which had been in operation since 1963. Like her predecessor, the new vessel is for operation on the European trade artery that is the River Rhine, and its tributaries. The Dive Bell Vessel 7012 (DBV 7012) will be used to search for and recover lost cargo or wreckage. In addition, she will be used for important river bed work and for construction inspections. Other duties include the production of barrel anchors in gravel or rocky areas, obtaining samples by drilling with liquid nitrogen, inspecting lock gates and buoy anchor points and even the removal of unexploded ordnance. This sub-surface maintenance system makes it possible for the little ship to travel and operate on the Rhine and Moselle Rivers (and other waterways such as the River Main) without the need to lower the water level for any such maintenance.

Unique to Europe

Ordered in February 2019, the highly unusual nature of the Dive Bell Vessel makes her unique to Europe thus far. The keel laying ceremony was announced on 25th October 2019 having taken place at Europoort Construction in Hendrik Ido Ambacht. This company had been subcontracted by Damen Shipyards to fabricate the hull. Damen’s piping department executed the main piping works during the block building stage at the company’s premises. With its proven track record in the offshore industry, Damen was confident that Europoort Construction would meet its high expectations for the project, and was not disappointed of course. Launched in July 2020, completion of the Dive Bell Vessel was announced on 11th January. The final construction and fitting out works of the ship were carried out at Damen Shipyards Hardinxveld located on the north bank of the River Merwede, and at Damen’s headquarters, Damen Shipyards Gorinchem. The Damen Shipyards Group needs no introduction to regular readers of Newbuild of the Month, a global company offering a vast range of newbuild designs whilst its family routes remain firmly in The Netherlands, being founded in 1927 in Hardinxveld-Giessendam by Jan and Marinus Damen. This location is just 10km from the present-day headquarters. Originally the €23 million vessel replacing the 1963-built TGS Carl Straat was to take on the name TGS Carl Straat. However, a change of heart occurred along the way and the name bestowed on the vessel was, rather appropriately, Archimedes. Archimedes of Syracuse lived from 287 B.C to 212 B.C and was a famous mathematician, physicist, engineer, astronomer and inventor. Leaving the “Eureka!” story aside, it is perhaps Archimedes’ principle of buoyancy that is the most relevant to the Dive Bell Vessel and her daily tasks. Archimedes not only determined that an object submerged in water displaces a volume of water equal to that of the object, he also found that the buoyant (lifting) force on that submerged object is equal to the weight of the displaced water. For divers, there is no escape from the principles that Archimedes so cleverly employed. For most purposes in diving, neutral buoyancy is preferred, to neither sink nor float. That said, the vessel now known as Archimedes allows diving operations in up to 10m-deep waters while providing a dry working environment. The application of overpressure in the steel bell blocks the passage of water, allowing the removal of obstacles, checks to be made etc in completely dry conditions at the river bed. The more general working depth will be 4m-7m but, even working at depths of up to 10 metres, no surface decompression is required. There is however a pressure chamber where the diving crew waits until the pressure is equalised to that in the diving bell. On return to the surface, the process is conducted again in reverse. For every metre of draught, 0.1 bar pressure is required. So, working at a maximum depth of 10 metres, the Archimedes’ diving bell requires 1 bar of pressure. The new diving bell system on board integrates the HAUX-Starcom and the HAUX-Bellstar hyperbaric chambers. Founded in 1980, HAUX Life-Support is based in Germany with over 1,500 chambers for various purposes delivered to date. The diving bell components include an entry lock, a lock conduit with a stairway, and a watertight caisson (dive bell) chamber, which is the main working area, with the capacity to accommodate 6 personnel. The caisson is 4m long, 6m wide and 2.7m high. A pull rod above the immersion tube creates a force parallelogram that holds the entire system in position. This ensures that the diving bell, which is reminiscent of an upturned margarine container in shape, always remains horizontal to the ship’s hull. The workers stand on a footbridge at the bottom of the bell and look for obstacles on the riverbed using long poles. For the recovery of items, the caisson is placed on the river bed and the pressure is increased again so that the remaining water is pushed out. After that, the dive team can walk on the river floor to work in the dry with the necessary equipment for the task being undertaken. Three crane systems attached to the chamber ceiling and several anchor points with a load capacity of up to 15 tonnes are also available to the dive team. There is also a side door in the caisson for loading equipment. Compared to the 1963-built version, the improved diving bell assembly is far more capable of handling the influence of underwater current forces and is also equipped with a HAUX-Fire extinguishing system. Construction, design and strength calculations of the system were carried out in the HAUX design office in Karlovy Vary, Czech Republic. The diving bell system has a total weight of approximately 160 tonnes. A 15-metre-long immersion tube connects the lock chamber via a long and fully enclosed staircase to the caisson. This is visible as a large steel tube that runs from behind the deckhouse to the diving bell and provides the crew with access to the pressure chamber. Large compressors direct air into the chamber and the immersion tube to build up the overpressure required for the respective working depth. This equipment is supported by a high-performance breathing air system, which also includes heating and insulation for the bell chamber. A single compressor is more than enough to prevent the chamber from flooding when submerged, but a second compressor is in place as a back-up. This applies to all onboard systems with everything being 100% redundant. In order to safely overcome the buoyancy of the diving bell system, 55 tons of ballast weight was also required, and this was supplied by Ancofer Stahlhandel GmbH in Cuxhaven and sister company JEBENS. In total, 33 parts with 7 different ballast weights in different formats were provided but no single ballast weight could exceed 2.5 tonnes. The diving bell assembly is raised and lowered hydraulically, with the supporting arm passing through a cut-out in the stern section of the vessel’s hull. The diving bell is suspended level with the ship’s hull at the stern whilst not in use. To hold position whilst working, an anchor system is provided by way of two 900g D’hone anchors situated forward and two 450kg anchors located aft, one each side of the bow/stern respectively. The vessel also uses a Spud Pole System for stability, one forward and one aft. These 15.90m long telescopic poles are hydraulically powered and lower beneath the keel to a maximum of 7 metres. When not in use, the poles can be stowed on deck so as not to create clearance issues with any bridges over the river.

Once in a Lifetime

The contract to build the Archimedes is quite possibly a once in a lifetime project for the team involved. Sadly, due to the COVID-19 pandemic, the delivery of the diving equipment to Damen was delayed, hence the main photo of the Archimedes shows her without the diving bell assembly installed as updated material was not available before the press deadline. As a result of the delay, the newbuild finally commenced full operations in late summer 2021 after delivery on 25th August in Duisburg, Germany. Prior to completion, the vessel remained at Gorinchem for crew familiarisation training. The authority responsible for the newbuild, WSA Rhine, was actually created just under a year after the newbuild was ordered. The Waterways and Shipping Office was formed on 30th January 2020 by amalgamating the previous waterways and shipping offices in Bingen, Cologne and Duisburg-Rhine. The WSA Rhine is based at the 3 locations of Bingen, Cologne and Duisburg and is responsible for the 370km long section of the River Rhine between Mainz (Rhine kilometre marker 493.5km where the jurisdiction borders on that of the Upper Rhine) and the German-Dutch border (Rhine kilometre marker 865.515km) plus the Rhine-Kleve shipping route.

The Archimedes is 69.56m long, making her 17m longer than her predecessor, with an overall beam of 11.76m, a hull depth of 3.20m and a draught of 1.70m. Displacement is 882 tonnes and the minimum air draught is 5.25m, a vital statistic for a river or waterway environment. Damen has applied the latest technology to the new vessel to ensure her suitability for future operations. She features high-performance diesel-electric propulsion compliant with EU Stage V standards, guaranteeing a constant cruising speed of 13 km/h. The service speed is a maximum of 15kph and the Archimedes can also undertake light towing operations if required, offering a modest bollard pull of 8 tonnes. Propulsive power is provided by a trio of Caterpillar C18 generator sets with onboard power provided via two Caterpillar C4.4 generators. The Caterpillar C18 Marine engine has a displacement of 18.1 litres, a rated speed of 1,800rpm, turbocharged-aftercooled aspiration, and maximum exhaust backpressure of 6.7kPa. A dry, keel-cooled C18 engine weighs 1,539kg while the heat-exchanger C18 weighs 1,673kg. The unit dimensions are, width-1,077.2mm, length-1,504.88mm and height-1,143.9mm. The diving bell ship is propelled by a total of three azimuth thrusters, two rudder propellers and a pump jet. All systems are driven by Marelli Motori E-propulsion motors electric motors. The twin 330kW SRP 150 FP rudder propellers each have a ducted propeller diameter of 1,100mm, which provides the necessary thrust. This enables the diving bell ship to reach a minimum service speed so, unlike her predecessor, can therefore operate on the Rhine without towing assistance. In combination with a 340kW SPJ 82 360º Pump Jet, the ship can be safely manoeuvred in a river environment. Thanks to the completely flush installation in the ship’s hull, the thruster jet is fully protected even in the event of grounding. The machinery spaces are located in the forward section of the hull at Tanktop level and amidships here can be found 8 cabins. On the port side are four 13.80m2 crew cabins whilst adjacent on the starboard side are three Officer’s cabins ranging from 18.00m2 to 20.00m2 in size plus a 13.00m2 cabin for visiting personnel. Beneath Tanktop level are the fuel and water tanks plus 17 ballast tanks to keep the vessel trim during her diving bell operations. The main deck layout of the ship makes her unmistakably a work vessel with a functional, no-frills layout. Situated forward on the raised bow section of the hull is the spacious, airconditioned and slightly offset to starboard telescopic wheelhouse, typical of what is found on many modern-day River Rhine cargo vessels. This provides excellent visibility for both navigation and work operations. Aft of the wheelhouse are the two exhaust stacks with the portacabin-like deckhouse on the main deck beyond, that accommodates all facilities for the crew of 7, including Captain, Diving Master, Chef, Engineer, Dive Manager, First Officer and Chief Engineer. These include a fully equipped kitchen, mess room, day room, changing room, toilets and showers and stores. Aft of the deck house is an open work deck, a storage area for a container and the diving bell assembly. There are also two Fassi F720RA he-dynamic 59.2t/m knuckle boom cranes on deck, situated forward (starboard side) and aft (port side). The maximum outreach is 20.70m and dimensions when stowed are 2.50m wide, 1.50m long and 2.45m high. At the time of writing no details were available regarding a naming ceremony for the Archimedes but the faithful Carl Straat was to be retained for a few months before retirement whilst the new vessel established herself. Will the Archimedes enjoy such a long career as her predecessor? Time will quite literally tell.