The Chittagong Dry Dock Ltd (CDDL) advertised a requirement to build 6 Offshore Patrol Vessels (OPV) for the Bangladesh Navy (BN) in joint collaboration with a reputed foreign shipbuilding company.
Shipbuilders from Europe, China and India expressed interest to jointly construct the Offshore Patrol Vessels with the Chittagong Dry Dock Ltd (CDDL). By the 29th day of February 2020 the Expression of Interest (EOI) invitation was closed.
The primary role of the OPV’s will be to maintain a constant presence in the maritime areas of Bangladesh for performing surveillance, perform constabulary duties such as policing, patrolling, anti-smuggling, fisheries protection and protection of offshore resources in the Exclusive Economic Zone (EEZ). The secondary role of the OPV’s will be provide disaster relief support and conduct search and rescue operations in the EEZ.
The Offshore Patrol Vessel (OPV) will be equipped with an aviation landing deck for support up to 11 tonnes class helicopter to perform primary and secondary roles including wartime employment in coastal areas. The OPV’s will carry two 20TEU mission orientated containers of 9 tonnes each.
With a full load displacement of around 2,000 tonnes offshore patrol vessel would be the largest warships to be built at any Bangladeshi shipyard. The OPV’s will have a minimum overall length of 85 m and a maximum breadth of 14 m. They will have a mean draught of 4 m at full load.
The OPV’s will have a maximum speed of no less than 20 knots and an economical speed of not less than 12 knots. The vessels should have a minimum endurance of 4,000 NM at economic speed.
They should be able to carry out operation at sea states of up to 6 and withstand up to sea state of 8.
Accommodation should be availed for 50 personnel including males and females. However there should be bunks that cater for 90 personnel. The facilities should include messing and recreational facilities for officers, sailors, conference and class room.
The Offshore Patrol Vessels (OPV) should be able to remain at sea for at least 30 days at a time and have a minimum annual usage uptime of 4,500 hours.
A minimum of two or more marine diesel engines connected to two shafts and CPP systems through reduction gear boxes in order to produce the desired speed. The propulsion system shall have automation and be controlled locally from engine room and remotely from machinery control room and bridge.
On deck armaments must include a 30 mm automatic gun integrated with the FCS and two 12.7 mm manual machine guns on either side of the flag deck.
The aviation deck should be able to operate a helicopter and unmanned aerial vehicles besides the OPV must have refuelling facilities.
Diving equipment such as diving sets, diving gears and diving set charging facilities must also be present.
In this regard Damen Shipyard’s Offshore Patrol Vessel 1800 Sea Axe (OPV 2) closely matches the EOI’s set out specifications. Damen, which already has a history of collaboration with the Khulna Shipyard is apparently poised to partner with the Chittagong Dry Dock Ltd (CDDL) to build Bangladesh’s largest warships to date.
Damen’s famous Axe-Bow hull design is used for the OPV, causing the vessel to be able to sail at speeds of up to 26 knots. Also it is a very fuel efficient vessel, due to the fact that the Axe-Bow hull was designed to have a low water resistance.
The OPV 2 is not only fast, it is also a comfortable vessel. The Axe-Bow itself was designed to lower the vertical accelerations (heave) of the vessel. In practice the largest acceleration ever measured on the bow of a Damen Sea Axe was 1.3 G. These low accelerations apply to all kinds of weather conditions, even stormy sea states.
Multi Mission locations on the OPV 2 take versatility to a total new level. Focus was given to the Bridge, Hangar and Bay. The new vessel is able to take mission dedicated equipment onboard, causing it to be lean and clean. The OPV 2 can sail out for missions like counter-piracy, counter-drugs, search-and-rescue and even anti-mining warfare.
The Bridge directly adjoins the Command & Control Centre (C&C Centre), ensuring easy and fast communication. Depending on the mission and the situation, the C&C Centre can be separated from the Bridge by means of a blinded sliding door. This will ensure that the C&C crew can fully focus on their tasks without being distracted, for instance during the tasking and planning phases of a mission.
When creating the recognised service picture, the C&C Centre will be in charge of collecting all necessary data. When targets on the radar cannot be identified, the C&C Centre officers can directly deploy an RHIB to visually identify the unknown target.
The actual engagement phase or ‘chase’, requires a lot of coordination and thus the number of activities per minute on the bridge normally is very high. On the new Damen OPV, the C&C officers will be able to see the situation with their own eyes directly from the C&C Centre, after the blinded sliding door has been lowered, taking away communication moments.
This reduces the workload on the crew involved, which is beneficial for the operation.
“Take what you need and leave the unnecessary.” This approach makes the OPV-2 versatile and mission focused. Missions can be related to such like humanitarian aid, counter-piracy, counter-terrorism and anti-drugs, anti-mining warfare (AMW), oil spill recovery, fishery inspection, search & rescue (SAR) and also everyday border security. For these missions different types of equipment is necessary.
The Multi-Mission Bay makes it possible to store dedicated equipment for the mentioned multifarious missions and even more. Mission modules (dedicated containers) can be lifted into the Multi-Mission Bay, through the helicopter deck.
If necessary, equipment stored in the mission modules (ROV, sonar, etc.), can be lowered into the water through the two PS and SB stern hatches.
Also one of the two 9 metre RHIBs is stored in the Multi-Mission Bay. A small slipway makes ultrafast RHIB deployment possible, while sailing.
Also quick recovery of the RHIB in sea states up to 6 BF is possible. A quick connecting hook takes in the RHIB quick and efficiently. Today’s high-tech and pioneering OPVs have “eyes in the sky”. Surveillance from the sky is essential for taking situation awareness to a higher level. Apart from a large helicopter, the Multi-Mission Hangar can store an Unmanned Aerial Vehicle (UAV) like the Boeing ScanEagle. Inside the Multi-Mission Hangar, the UAV can also be maintained in a dedicated UAV-workshop. Launching and recovery of the UAV is carried out from the helicopter deck. Constant communication between the UAV and the Multi-Mission Bridge assures that all details in the area are spotted. The new OPV can handle helicopters up to 11 tonnes, like the NH-90. The hangar is large enough to store large helicopters and also to execute maintenance. Also the hangar is equipped with a helicopter spare parts store and workshop.