A worldwide demand for new tugs of all types is putting enormous pressure in all sectors of the shipbuilding industry and its suppliers. Building capacity in conventional specialist shipyards is at a premium and heavy demand for engines and major components is, in many cases, affecting delivery dates. There are many examples of full order books and unacceptably long delivery dates (2010-2012 for new orders) being quoted for new tugs by some yards.

In the current climate Damen is still able to react favourably to the high demand for large numbers of tugs at competitive prices. The Damen T&W team are continually reviewing the available building capacity in various parts of the world and production has already been increased considerably. New yards have been developed and joint ventures formed to ensure that construction takes place in locations where labour rates are competitive and Damen standards can be readily achieved.

A considerable proportion of the company’s current production is carried out at the Damen Galatz shipyard in Rumania, the Damen Changde shipyard in China and two yards in Vietnam. The Galatz shipyard is to have its capacity expanded considerably, the Changde facility is due to be doubled in size and a second Chinese shipyard is planned. A new company, Damen Marine Components Suzhou, has opened a production facility in China where nozzles and other marine components will be manufactured. A further shipyard, with a planned capacity of 30 vessels per year is to be built on a 40 hectare site in Vietnam to supplement the joint venture yards already in use.

Late in 2006 Damen Gorinchem reported approximately 55 tugs delivered, 25 of which were ASD tugs of various designs. Since the first ASD tug, the ASD Tug 3110, was introduced in 1995, over 200 have been sold. The ASD 3110 remains popular with clients in spite of many other designs becoming available. Among the most successful products is the ASD Tug 2810, with a bollard pull of over 50 tons, that has been ordered in large numbers for shiphandling duties by Smit, Bourbon and other major operators. The more powerful ASD Tug 3111, with a bollard pull of 66 tons, is widely used. The terminal tug ASD Tug 3211 and smaller ASD Tug 2609 are also popular.

At the time of writing, shipyards in the Damen Group have 75 tugs under construction to fulfil firm orders. A further 50 fully fitted vessels are being built for stock, which usually means for almost immediate delivery once completed. Some 40 to 50 hulls are also in production and will be fitted out to fulfil specific orders or held ‘on-stock’.

Another burning issue for tug owners contemplating new vessels is that the high demand is also having a serious ‘knock-on’ effect on the availability of marine diesel engines and propulsion machinery. To a large extent Damen is suffering less than most yards due to the very long term relationships it has formed with suppliers such as Caterpillar for marine diesel engines and Rolls-Royce Marine for azimuthing propulsion units. Some 95% of Damen tugs now in production are to be fitted with Caterpillar main engines. One of the advantages of large scale series production is that supplies of major assemblies of this type can be pre-planned on a long term basis. The Damen Group, now comprising over 40 companies, also manufacture many major components such as winches, running gear and nozzles. The supply of those items can also be pre-planned.

Working in conjunction with the sales team, the T&W division conducts a continual review of towage industry requirements, gathering information from careful market research and a close working relationship with customers from all over the world. The Gorinchem based design team carry out a rolling programme of product reviews on all existing designs and progressively modifies and, where necessary, redesigns established vessels to ensure they remain viable in today’s market place.

Two recent examples of this redesign process are now in full production and will soon be delivered to customers and available from stock. The smallest of these is the new StanTug 1606. Developed from the well established StanTug1605, the new version of this 16.54m tug will have Caterpillar main engines producing a total of 1,200 bhp to power a pair of fixed pitch propellers rotating in high efficiency Van der Giessen ‘Optima’ nozzles. This will give the vessel a bollard pull of over 15 tons, a 40% increase over the earlier version. An additional 1m in the beam offers greater stability and the space for a more powerful propulsion system. A bigger brother, the StanTug 1907, has been given similar treatment. Both vessels are now in full production in Romania and China, and with some orders already on the books both will soon be appearing in western Europe. Other vessels in the Stan Tug range have been similarly revised in recent years and examples of those, such as the StanTug 2208, have already been reported in Maritime Journal.

New designs are constantly under consideration, allowing the sales staff to react swiftly to new demands for particular types of vessel. The need to provide small, compact tugs for safe operation with very small crews is a good example. More compact tug designs are to be introduced and existing designs refined to improve safety, simplicity of operation and maintenance as well as ease of production. Developing situations, such as increasing LNG traffic, have been anticipated and met with powerful tug designs configured to meet the particularly high standards set by the LNG industry.

In 2003 the company introduced its first true compact azimuthing stern drive (ASD) tug, the Damen ASD tug 2411. Many examples of the 70 tons bollard pull ASD 2411 are now in use in Australasia and Europe and production continues in China and Vietnam. The design places great emphasis on the ability to operate the 25m vessel safely with a very small crew. Since the first vessels were delivered to operators such as Adsteam (in Australia and the UK), a number of refinements have been incorporated with a view to two man operation. The level of engineroom automation has been increased and items such as electrical switchboards have been relocated above main deck level, reducing the need for access to the engineroom while the tug is underway. Wheelhouse controls have been improved to give the tug master the ability to control the ‘whole tug’ from his Captain’s chair. This now includes operation of the towing winch and radios by means of foot operated pedals. Bulwark height has also been increased to 1.1m to improve safety of personnel on deck.

Two other new projects in the ‘compact tug’ category are rapidly coming to fruition after extensive research and tank testing. A yet smaller ASD harbour tug, the ASD 2310 is to be introduced to replace the existing ASD 2509 that is to be discontinued. The new design follows very closely the ASD 2411 concept and will incorporate many of the lessons learned during the development of that vessel. Two prototypes of this new, highly agile 50 ton bollard pull design are now under construction, with delivery scheduled for 2008.

Another significant development is the introduction of a ‘compact’ tractor tug with a fully azimuthing propulsion system, designated the Damen ATD Tug 2412. This is an important departure for Damen who have not included a tractor tug in their product range for many years. A market opportunity has been identified for tugs of this type. The new vessel will measure 24.65m in length overall, with a beam of 12.63m and draft (aft) of 5.85m. Two Caterpillar 3516B TA HD/D main engines generating a total of 5,605 bhp will be installed to power a pair of Rolls-Royce US255 propulsion units with ‘built-in’ slipping clutches. A bollard pull of 62 tons is anticipated and a maximum speed of over 11 knots. Accommodation for up to four persons will be provided and the vessel will be fitted out with extensive vibration and acoustic insulation. The first two tugs are currently under construction.

At the other end of the scale, the design team at Damen T&W Gorinchem has turned its attention to the needs of the oil and gas terminal operator. A larger and more powerful terminal tug will soon be offered to clients in addition to the well established ASD Tug 3211. Designated the ASD Tug 3213, the new tug is intended for tanker handling and escort operation in exposed locations and the hull form will incorporate a very deep box keel and pronounced sheer aft, derived from work carried out in conjunction with the Marin ‘SAFETUG’ project. The vessel has the same 32m overall length as its stablemate but will have an impressive 13.29m beam. Considerable effort has been made to enhance stability with the increased beam and by reducing height. The superstructure follows current Damen practice and all crew accommodation is above the waterline.

Damen has high hopes for the new CaterpillarC175 16V/C engine that will power the ASD 3213. Two such engines will generate a total of 6,920 bhp, each coupled to a Rolls-Royce US 285 propulsion unit embodying a 3m diameter fixed pitch propeller. A bollard pull ahead of 82.5 tons is anticipated and 75 tons astern, with a maximum speed of 12.5 knots. A heavy duty towing winch, with a brake holding load of 250 tons and two independent drums, will be fitted on the foredeck. A range of customer options will be offered, including a towing winch aft and a full FiFi 1 fire fighting system.

Preparations for production of the ASD 3213 are almost complete and construction of the first vessels is scheduled to start in May of this year.

An integral part of the design process is to enable series production methods to be refined. At the very heart of Damen Shipyards success, since its inception in 1968, has been carefully controlled series production of well conceived standard designs. The process of standardisation continues relentlessly, with every feature of each design scrutinised with productivity in mind. Procedures used in the various shipyards are formalised and carefully controlled but with sufficient flexibility to allow improvements to be made locally.

For simplicity of design and economic production, many common features are developed that can be applied to several vessels in a product range. Hundreds of common features can be found in hull and superstructure construction, fitting out of accommodation and wheelhouses and the positioning of equipment in the engineroom. Small details are carefully considered and where possible a high degree of commonality is applied. This has important advantages not only for the shipyard but also for the tug owner. Maintenance and repair are simplified, spare parts are easier to control and crew familiarisation is made much easier.

Among the many items to be studied recently and redesigned by the T&W design team are the control consoles installed in tugs, particularly in the ASD range. In order to improve the layout of controls and find a common standard, crews from several Damen clients were invited to inspect and comment on mock-ups of the control console, thus bringing to the process a high level of operational experience. As a direct result of this recent exercise, a control console of the same design is to be introduced to virtually all ASDs in standard production.