New anchor handler set to take the strain

Like the shipping industry, the offshore industry can be a very conservative business. New concepts and new ideas are not always taken up as quickly as they might be in an industry where the ?bottom line? is so important and margins so slim.

If, however, a new idea can save the shipowner money by significantly reducing what is probably his biggest recurring cost ? the cost of the fuel he buys to put in his ships? bunkers ? then that idea has a chance of being adopted.

This is the principal advantage promised by a new type of anchor handling tug supply (AHTS) vessel designed by a Norwegian company, ERAM, based on Alesund on the west coast of Norway and founded by Even Remoy, a well known name in Norwegian shipping circles. The company also employs two naval architects who played a major role in the development of Marin Teknikk?s MT series of offshore support vessels (OSVs).

Remoy founded ERAM with the goal of developing a design for what he calls the first “full blooded” diesel electric anchor handler. Traditionally such ships have mechanical machinery as this has seemed the best way to produce the required bollard pull. ERAM also describes the resulting design as a True Multi-Purpose Vessel (TMPV). It is part of a portfolio that includes Platform Support Vessels (PSVs) and multi-purpose Remotely Operated Vehicle (ROV)/PSV vessels, all of which use diesel electric propulsion because of the perceived reduced life cycle costs of this type of machinery.

Although large numbers of anchor handlers and PSVs are being delivered at the moment, the market for OSVs is in a bit of a trough at present. Rates for AHTS and PSVs in the North Sea have been very soft for the past 12-18 months because exploration and production activity by the oil majors that the OSVs support has been at a low level. However Remoy is confident that when the market picks up the reduced fuel consumption and flexible nature of the multipurpose design will be of real interest to owners, even in spite of strong competition from established designers such as Rolls-Royce Marine, Vik Sandvik, and Ulstein

“Apart from the low lifetime costs of the design, its flexibility will mean that it enjoys a high level of utility, whatever the market,” Remoy explains.

While the design has been greeted with great interest, some of ERAM?s competitors have suggested that diesel electric may not be the best way to produce the bollard pull necessary to tow a rig (bollard pull being the calculation of the ?pull? or strain a tug is capable of producing when towing ? it is generally tested by heaving around a bollard and is measured from zero to actual towing speed).

Remoy agreed that bollard pull is very important for an anchor handler, but isn?t fazed by the idea of adopting a totally new way of producing it. “We have a number of different configurations that we can use to produce bollard pull using diesel electric drive,” he explains.

“The baseline anchor handler we are proposing can produce a bollard pull of 200t. Operators we have spoken to at length, such as Statoil, tell us that 200t bollard pull is sufficient for 99 per cent of the work they need, but we also have a version of the vessel that can produce a bollard pull of 250t which we have discussed recently with an owner who came to us and asked for just that.”

Remoy says that ERAM is talking to two companies who offer diesel electric machinery for the new AHTS, although for commercial reasons he cannot reveal who they are. “We expect to make a choice between the vendors shortly,” he explains.

The diesel electric machinery in the baseline design would drive two fixed pitch propellers in nozzles, each absorbing 3,500kW (contra-rotating azimuthing propulsors with fixed pitch propellers ? such as Rolls-Royce Marine?s well known Contaz gear with variable speed motors are an option when anchor handling duties are not required).

Diesel electric machinery apart, the ERAM anchor handler has a specially designed hullform tested at Marintek-SINTEF in Norway, which should ensure that it has among the best seakeeping characteristics of ships of its type, creating a stable platform that is safe and comfortable to work on.

At around 92m length overall with a moulded breadth of 23m, and a deadweight of 3,800t at 6.5m draught (6,490t at 7m draught), the ERAM AHTS is a sleek looking vessel, built to DNV class including DYNPOS AUTR or AUTRO, depending on the owner?s specific requirements. The design also bears DNV?s ?Clean? and ?Comfort? class notation, and has the option of carrying FiFi I and II firefighting gear and oil recovery equipment.

Fitted with a three-drum, 400t low pressure hydraulic winch (with a 500t winch available as an option), the ERAM AHTS can transport 3,300 tonnes of cargo at slightly in excess of 16 knots on around 35t of fuel per day. Deck space available is some 1,000m2 with an allowable deck cargo load of up to 4,000t. The ship can also carry the full range of supplies, including 500m3 of dry bulk and 200m3 of methanol. Two deck cranes are also specified, one of 10t/15m, for general duties and for handling ROVs, and another, on a cargo rail, rated at 5t/10m. n

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ERAM?s diesel electric AHTS emphasises low operating costs, safety and good seakeeping

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