(DRSV) ST-236 – Ultra Deep Submarine Rescue

Length over all 86.00 m
Breadth moulded 20.00 m
Displacement 6200 T

in collaboration with Skipsteknisk

(DRSV) ST-236

The 236 ST (Diving Rescue Support Vessel) is capable of performing Submarine Rescue Operations up to a depth of 650msw thanks to the moon pool launched Drass Submarine Rescue Vehicle (SRV). The vessel is equipped with a compact 9-man in-built Saturation Diving System rated to 300msw. The vessel hosts an in-built Drass Submarine Ventilation System rated for 650msw and a Working ROV. This vessel design is suitable to operate in extreme sea conditions.


DRASS SRV is a modern, effective and reliable rescue vehicle, remotely operated and launched from the moon pool. DRASS SRV is capable of the most extended endurance in intense weather conditions – operating in very rough seas and connecting to the DISSUB even during extreme angle inclination.
The SRV moon pool launch offers the highest reliability and safety standards even in extreme sea conditions thanks to the rail guides and protection of a passive cursor. The cursor extends outside the ship keel, protecting the SRV from accidental bumping against the hull. The main wire pulls the SRV gently into the cursor which is conically shaped to connect with the entrance of the SRV frame.
The heave compensation system keeps the SRV position stable from vessel motion, easing the connection of the SRV with the recovery frame. A safe connection of the SRV is also enabled by the guide umbilical.
The main advantages of Drass SRV compared to traditional rescue solutions are as follows:

  • The vessel moon pool allows the launch and recovery of the SRV during severe sea conditions
  • Reconnection of the SRV is autonomous, therefore no assisting vessel is required to recover the SRV
  • The training of the SRV pilots can be equivalent to a Working ROV training course, and is therefore available without the expense of actual vessel operations
  • The recovery of the SRV in case of failure is guaranteed by several emergency recovery modes
  • The system requires only a winch and a heave compensator system on top of the moon pool, leaving all the available space on the main deck and optimizing the vessel’s general arrangement.

The SRV is a flexible underwater transportation tool and, thanks to its modular design, once removed, the Submarine Rescue Capsule can be used for multifunctional subsea activities. Through a standard mechanical and signal (should this say ‘signal’ or ‘single’) interface plate, the WROV module of the SRV can transport different payloads. This characteristic gives to the same Rescue Diving Support Vessel an unprecedented flexibility to perform unlimited subsea tasks.
The most common can be described below:

  • Defence and Deterrence: Installation, removal and maintenance of underwater protection systems for harbours and susceptible sites
  • Defence and Deterrence: Extension of vessel stand-off for mining/de-mining activities
  • General Purpose Subsea Operations: Intervention with WROV capability up to 2000msw
  • Environmental Support / Research & Development: Deployment of underwater system for drilling and sludge sampling
  • Environmental Support / Research and Development: Sea water sampling for the detection of microplastics and various contaminants
  • Environmental Support: Detection containment and remediation systems for radioactive or toxic waste sites