Ship & Boat International eNews: March/April 2021
The UK recreational boat market seems to be going from strength to strength despite, or perhaps because of, the ongoing COVID-19 chaos. Whether to escape the stultifying effects of three successive lockdowns, or to simply enjoy summer breaks while avoiding hotel quarantine, British boaters have been taking to the waves in droves since March 2020.
Beautiful boats deserve beautiful marinas, and the increasing popularity of recreational boating has led to a number of these facilities, spanning 4,000 miles of British coastline, undergoing cosmetic overhauls. One such site is Burry Port Marina, situated in Carmarthenshire in southwest Wales, which offers 450 berths, three harbours and a slipway. This is one of five Welsh marinas owned by The Marine Group, the others being located in Cardiff, Aberystwyth, Port Dinorwic and Watchet.
To bring Burry Port Marina “back up to standard”, The Marine Group is utilising dredging vessels to develop the channels and berths at the site. Two dredgers are currently in operation: CMS Innovation and the bespoke CMS Seaka, which both use water injection dredging (WID) technology to meet this goal. “CMS Seaka was originally a multicat being used by another dredging company,” Rhys Jones, contracts manager at The Marine Group, tells Ship & Boat International. The Marine Group originally purchased the boat in 2018, with the intention of converting her into a water-injection dredger – a task that was subsequently handled by naval architect and offshore support vessel specialist OSD-IMT.
The boat was then rebuilt as a joint project between The Marine Group’s engineering subsidiary Cardiff Diesel Services and her original builder, GRA Ltd. “The whole process took around 16 months; unfortunately, progress was slowed by the pandemic,” says Jones. The key result of the overhaul was increased efficiency for CMS Seaka, enabling her to dredge in higher volumes than before. The 30tonne vessel measures 10m x 4.8m, draws 1m and is manned by a crew of two: a skipper and a deck hand. “The crew work in six- or 12-hour shifts,” says Jones. “She is, however, coded for three persons.”
CMS Seaka is powered by a Doosan V158TI engine, driving propellers. Her compact size makes her road-transportable, meaning that she can be hired out and conveyed to other sites across the UK when not busy at Burry Port. “She will also have a hand in developing our newest acquisition, Watchet Marina, and has the ability to engage with wind farm operations,” Jones reveals.
Already, CMS Seaka is proving her worth: “The impact she’s having on Burry Port is remarkable,” he continues. “We started tackling the tougher sand banks within the marina to really test her capabilities. We found that while she was having a visible and rapid impact on the sand banks, rearranging the nozzles to a different angle allowed a much greater volume of sand to be removed from the marina. The crew are growing more confident with her each week.”
CMS Seaka has been equipped with a Sulzer A53-200 water pump, rated 330litres per second. Following her overhaul, the vessel can dredge to depths spanning 1.5m to 8.5m, and at a rate of 450m3 per hour in soft material, courtesy of a 5m boom holding 27 outlets. This is a notable step up from her fellow dredger, the 9.6m x 3.9m CMS Innovation, which has a maximum dredging depth of 8m and a dredging rate of 150m3 per hour.
In addition to WID’s reduced impact on the environment, proponents stress the method’s cost-effectiveness. “With regard to licence applications to the Marine Management Organisation [MMO – the body responsible for marine planning and licensing in UK waters], there is no requirement for an additional disposal licence, allowing dredging to be undertaken with only a marine licence for dredging,” says Jones. “It’s also a great option for harbour authorities that work under a Harbour Act or Order. These can allow the harbour to dredge without the request for licences at all, as the sediment is retained in the water column.”
WID can also prove cost-effective during the dredging campaigns. “By its nature, WID does not have to steam out to a disposal area miles away to dump sediments, allowing more actual dredging time and lower fuel costs,” Jones highlights. “The plant involved for WID is generally smaller than that for traditional dredging, enabling engines to be more efficient.”
Additionally, the smaller sizes of WID dredgers permit these vessels to enter hard-to-reach areas that bigger ships, carrying larger plant, cannot access – and, capable of running with a skeleton crew of two or three, there’s a corresponding saving in personnel costs. Although cases will obviously vary depending on the size of the dredger, the size of the port or marina and/or the scope of the project, Jones estimates that a WID vessel can be operated “for around 25-40% of the total cost of a traditional dredging vessel”.
