Two dive support vessels being built for a company working off Angola are among the latest designs from Incat Crowther, the well known naval architect in Australia
Incat Crowther regularly appears in the Annual Review issue of OSJ as a result of the innovative vessels it designs and the niche markets in which it specialises such as crewboats and dive support vessels. Crewboats designed by the company are described elsewhere in this issue.
It now has a number of dive support vessel (DSV) designs to its name, of which some are catamarans and others monohulls. The largest of these is a 56 m catamaran DSV, Bhagwan Dryden, which has a first-of-type fully integrated catamaran hullform unit with multiple power generation units coupled to an advanced control system and azimuth propulsors and deck equipment.
Others include Oceanicasub IV and Oceanicasub V, two 43 m DSVs with a wide array of dive support equipment, including a deck crane, A-frame for a remotely operated vehicle, dive bell frame and hyperbaric chamber, and a 42.5 m monohull DSV, Sistac Victoria, a purpose-built unit with fully integrated dive systems.
They are complemented in its design portfolio by two 18 m catamaran DSVs, which were ordered from the company early in 2017 by Legacy Marine Group of Port Elizabeth, South Africa.
Currently under construction, these catamaran hullform DSVs are being built for Stapem Offshore for operation in the coastal waters off Angola, Stapem Offshore being a provider of marine, subsea and maintenance services to companies in the offshore oil and gas industry that has been operational in Angola since 1989 and in Congo since 2009. It specialises in multidiscipline engineering, procurement, construction, and commissioning and maintenance projects and has an operating base in Sonils Base with warehouses, workshops, storage yards, transportation facilities and accommodation.
Stapem Offshore’s new vessels are a customised design specific to supporting dive operations offshore West Africa where they will work closely with floating production units and other platforms.
Incat Crowther describes the bow configuration as designed for efficient interaction with personal transfer ladders on floating production, storage and offloading (FPSO) units and fixed platforms. Robust fendering is to be provided around the perimeter of the vessel to protect it from damage.
The aft deck utilises available space by combining deck lockers and racks for dive equipment storage with a covered dive prepping area. The vessel will have four fold-down dive ladders for water access and three swing davits to assist divers plus a deck crane for additional operational support. The main cabin has seating for 12 and a dive operations panel for monitoring dives.
Designed to achieve speeds in excess of 20 knots, the vessel’s propulsion takes the form of two MAN D2876LE402 main engines, each coupled to a Hamilton HJ403 waterjet through ZF 360 gearboxes.
Electrical power for the vessel and all dive operations will be provided by two Fischer Panda generators. Other items fitted below deck include a hydraulic power unit with its own designated engine and pump, a Caviblaster system, high-pressure and low-pressure compressors and storage systems.
With a waterline length of 17.0 m and a beam of 6.0 m, the newbuilds for Stapem Offshore will have a hull draught of 1.16 m. With a crew of two, the new units will have two fuel tanks, each for 1,750 litres of fuel, and tanks for 500 litres of water and 500 litres of sullage.
The newbuilds will have a service speed of 20 knots and maximum speed of 23.5 knots. They will bear the class notation ABS +A1 (E) HSC Coastal Craft + AMS.