In 2006 Acta Marine and Alphatron Marine pioneered the use of Dynamic Positioning technology on the shallow water work vessel Sara Maatje II (now Coastal Conquest). Since then there have been another four multi cats, each fitted with the excellent DP systems made by Navis. The last of these, the shallow draft support vessel Coastal Chariot, was delivered in February 2014 in class BV (DP-1), like her sister ship Coastal Challenger. DP gives these vessels much greater operational readiness.
Henry van de Weijer, responsible for supervising the construction of multi cats at Acta Marine, explains: ‘As the existing craft essentially were not configured for use with a DP system at the time of the first project, the engineering and installation became quite a challenge for Alphatron and the Russian/Finnish manufacturer Navis Engineering: the steering gear, the signals from the motors and the reversing gear all had to be matched to the DP system. Not without success, however. The vessel performed well with DP, offering new potential uses for our multi cats as a result. Alphatron's experience and tenacity, coupled with their commitment from the first talks right up to delivery and after-sales service, were greatly appreciated.’
Acta Marine currently has ten craft of the multi cat type in operation, and four of these are equipped with a Navis DP system. The Navis DP-1 system on the Coastal Chariot and its identical sister vessel Coastal Challenger gives Acta Marine its best-ever performance whilst saving on fuel consumption. ‘The economical performance can be attributed to the decision to use bow thrusters which, thanks to the azimuthing control device, can set the thrust to the desired direction. In addition, the configuration of the DP system also has an impact on fuel consumption. The necessary attention was focused on this aspect during the test voyages, both by our shipping line and the people at Alphatron and Navis,’ says Van de Weijer.
Three craft were deployed for a survey project in 2007 in Kazakh waters of the Caspian Sea. ‘A significant requirement for these vessels, which Navis was able to meet, was that the system should offer waypoint tracking at low speeds. Another important consideration in the selection of the Navis DP system was the Russian support,’ says Van de Weijer. The Coastal Chariot can be deployed for projects in the dredging, oil and gas industries, as well as in off-shore wind farms, sea-bed analysis (Coastal Challenger) and laying telecommunications cables. The Coastal Chariot and Coastal Challenger are unique due to their restricted draft of just 1.80 metres combined with a tractive power of 37 tons. This makes them particularly well suited to work in ultra-shallow waters very close to the coastline.
In addition to DP, Alphatron also supplied the complete navigation and communications equipment for the bridge of the Coastal Chariot and, before that, for the bridges of the Coastal Challenger (2012) and Coastal Discovery (2009), largely manufactured by JRC (Japan Radio Company).