Diving Support Vessel (DSV)

Diving Support Vessels (DSV’s), also known as Subsea Vessels, are vessels that carry out a wide range of subsea activities typically through the deployment of divers. DSV’s are most commonly used to carry out inspection repair and maintenance (IRM) on subsea pipelines and other infrastructure and to support the installation of subsea infrastructure and pipelines. DSV’s may also be modified to conduct cable-lay and/or well intervention activities.










Category Description Image

Category Description

Diving Support Vessels (DSV’s), also known as Subsea Vessels, are vessels that carry out a wide range of subsea activities typically through the deployment of divers. DSV’s are most commonly used to carryout inspection repair and maintenance (IRM) on subsea pipelines and other infrastructure and to support the installation of subsea infrastructure and pipelines. DSV’s may also be modified to conduct cable-lay and/or well intervention activities.  

Diving Support Vessels are built with many of the features seen on Multi-Purpose Support Vessels such as Dynamic Positioning System (II or III), large accommodation, helideck, Remote Operated Vehicles (ROV), and subsea active heave compensated crane (pedestal or knuckle boom) however also integrates a saturation diving system.


Cranes: Most DSV’s come with large capacity subsea cranes capable of handling loads in deep water (over 3000m in some instances) and at weights ranging from 100t to over 400t. Typically cranes are active heave compensated (AHC) meaning that the control systems of the crane are capable of keeping the load motionless irrespective of movements of the vessel.


Air Diving Systems: Most DSV’s will have permanent air or mixed gas diving system.  Air or mixed gas diving is used at depths typically no greater than 50m depending of the mix of gas used. At any greater depth than 50m saturation diving is preferred to avoid the risks of decompression sickness and allow divers to work at depth for longer. Air or mixed gas diving relies on the supply of breathing gas from the surface. Gases used may be oxygen, or a mixture of oxygen and nitrogen (Nitrox) or oxygen and helium (Heliox). Oxygen and nitrox are used at shallower depths (50m) with heliox and provide a bottom time of no more than 50 minutes at such depth. Likewise, Heliox may be used down to 75m however with only 30 minutes bottom time. Depending on the working depth divers may be lowered to depth in a basket or a wet bell.

Typically Air or Nitrox diving requires a team of 5 (Diving Supervisor, working diver, stand-by diver, tender for working diver, tender for stand-by diver), whereas a team of 7 is required in Heliox dives (Diving Supervisor, working diver, stand-by diver, tender for working diver, tender for standby diver, short notice surface standby and tender) 


Saturation Diving Systems: All DSV’s will have an integrated SAT diving system capable of accommodating as many as 24 people. The main component of a SAT diving system are:

  • Personnel Transfer Capsule - The PTC is a spherical, submersible pressure vessel that can transfer divers in full diving dress, along with work tools and associated operating equipment, from the deck of the surface platform to their designated working depth.
  • Deck Decompression Chamber (DDC) - The DDC furnishes a dry environment for accomplishing decompression and, if necessary, recompression. The DDC is a multi-compartment, horizontal pressure vessel mounted on the surface-support platform. Each DDC is equipped with living, sanitary, and resting facilities for the dive team. A service lock provides for the passage of food, medical supplies, and other articles between the diving crew inside the chamber and topside support personnel.
  • PTC Handling Systems. Of all the elements of DDS, none are more varied than PTC handling systems. Launch and retrieval of the PTC present significant hazards to the divers during heavy weather and are major factors in configuring and operating the handling system.

SAT diving enables divers to live and work at depths greater than 50m for days or even weeks at a time. This allows for a greater economy of work and enhanced safety for the divers, since, after working in the water, the divers can rest and live in a dry pressurized habitat onboard the DSV at the same pressure as the work depth. A mixture of helium and oxygen (Heliox) is typically used for breathing as such removes the risk of illness and allows divers to remain in a saturated state for as long as 28 days and operate at depth to 600m

Team size consists of a minimum of two Diving Supervisors, one Life Support Supervisor, 1 Life Support Technician, two divers, two stand-by divers on the surface that are saturation qualified, and a dive technician.

Modular saturation diving systems may be used onboard the main deck of a vessel, such as a Multi-Purpose Support Vessel. This mode of the diving operation is more weather-sensitive as the diving bell is deployed over the side of the vessel versus an integrated diving spread which deploys the diving bell from the centre line of the vessel hull.


Remote Operate Vehicle (ROV): All DSV with come complete with at least one work class ROV and may even have two. Work class ROV’s large enough to carry sensors and/or manipulators. Larger work class ROV’s also often have multiplexing capability that allows additional sensors and tools to operate without being “hardwired” through the umbilical system. Depending on the type the size of ROV some may be rated to work in up to 4000m of water. Other common equipment used in conjunction with the ROV are:

  • Launch and Recovery System (LARS) – a piece of deck machinery (A-Frame or other) that is used to safely place the ROV into the water.
  • Tether Management System (TMS) – a piece of subsea equipment(top hat or side entry cage) that is lowered with the ROV from which the ROV can “fly” away from to work. Instead of being connected directly to the DSV, operating via a TMS allows the ROV to move without impact from forces placed on the vessel or the long length of umbilical to/from the DSV.


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Supply & Demand Dynamics

The demand for DSV’s in general continues to be driven by the world's increased energy demands. According to BP Energy Outlook energy demands will continue to grow at a pace of about 1.2% per annum until 2040 with oil and gas remaining the dominant source (circa 55%). 


Demand Outlook

The DSV market never fully recovered since the 2014 oil price crash and any gains over the previous years have been completely lost following the Covid pandemic and the resulting crash in oil price. With oil price lower it can be expected that operators defer Inspection, Repair and Maintenance (IRM) campaigns until oil prices recover. Major EPC contractors during 2019 and 2020 have reported record backlogs and projects very few project cancellations however DSV owners are reporting changes to commencement dates. The DSV market is expected to remain at less than 50% utilization with bearish prospects for the foreseeable future.

With demand never really recovering rates remain close to the bottom leaving many DSV owners with liquidity issues.

Supply Outlook

The current worldwide DSV fleet is made up of ~80 vessels. The market is fairly fragmented with 50+ owners operating these vessels most of which only operate a single vessel. Ultra Deep Solutions (UDS) operate the largest fleet of 5 x DSVs. The supply side should improve over the coming years with few new builds ongoing and a significant portion of the fleet older than 20 years of age, especially in shallow water regions.

Below is a regional supply view of the major DSV companies.

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Key Players

Regulations & Safety

IOCs and NOCs have developed their own technical and operational compliance manuals to assess DSV's. The International Marine Contractors Association (IMCA) provides advice on ways in which diving and ROV operations can be carried out safely. Reputable DSV owners are qualified with IMCA, and IMCA’s website provides the list of these organizations on their website which comply with its guidelines. Click here to view the IMCA directory.


Diving Support Vessel (DSV) Companies and Suppliers

The DSV market is highly fragmented. With ~80 DSV's operating globally over half are single vessel companies. Below is a list of the major DSV Companies who own 2 or more vessels. 


Click here for a full list of Diving Support Vessels.

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Portfolio Positioning

Currently we see spend within the Diving Support Vessel category sit in the “Leverage” quadrant of the Kraljic Matrix (low supply risk, high value) however this can become “Strategic” dependent on competing project timelines and specification of vessels.

At present buyers are in a strong position with low demand and high competition between owners. Track record and relationship have a strong influence in buyer’s decisions.


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Cost & Price Analysis

Price Analysis

Current Diving Support Vessel rates face downward pressure; however, the market is close to bottom with little further room to maneuver. As seen with many of the major DSV owners’ margins have been minimal or negative and there have been a number of owners who have been through bankruptcy proceedings such as; Harkand, Hallin Marine and Ethos Offshore.

Depending on the region, availability of air diving or saturation diving spreads onboard,  and spec of the DSV rates can range rates can range from 15k per day up to $90k per day. Lowest rates are normally seen in the shallow water of SE Asia, India and Middle East.

Cost Analysis

The main cost components associated with DSV’s are the capital depreciation and the operating costs (crewing, provision, maintenance, insurance and radios) that can represent up to 80-95%.

Other significant cost components are overheads and interest expense. Given the current market conditions theses cost components will vary significantly depending on impairments and the company's ability to restructure its debt. 

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Total Cost of Ownership

Parameter Service Cost Performance Cost
Cost Visibility High Medium
Description The rates and charges agreed in a contract The cost of inefficiency
Cost Driver
  • Daily Hire Rate or Lump Sum
  • NPT (breakdown)
  • Learning Curve
  • Quality of work
  • Project delays
Commercial Impact High Depends of Commercial Risk Model



Given the current market conditions any strategy should be focused on increasing competition, establishing a commercial risk framework and securing availability . Below are a few strategy options to consider:

Specification – Depending on the work scope buyers may have some flexibility in the specification of the vessel and decisions such as air vs. saturation, purpose built DSV or MPSV or lay vessel, and Work Class ROV vs Observation Class ROV should be answered. The more capability on-board the vessel the higher the rate therefore care should be given to specifying the requirements to deliver the scope.


Understand the Market – For complex installation projects higher specification DSV’s can be highly sought after and can demand high rates. This can drive prices upwards of $90,000 per day. Be sure to understand availability in the market engaging suppliers early to ensure DSV will be available.


Competitive Tender - Ensure scope and/or specifications are well defined and engage multiple suppliers/contractors early to secure availability and favorable pricing. 


Commercial Model – In complex Greenfield developments the installation portion of the scope may be provided by one supplier as an EPCI package providing synergies and efficiencies through the integration of the different project stages. Traditionally an EPCI package has been provided on a lump sum basis however as projects increase in technical complexity many suppliers have sought to de-risk this moving towards unit rates. The EPCI model should be considered against a separate installation contract.

Parameter Lump Sum Reimbursable
Description Lump Sum for agreed scope Unit rates, Mob and Demob
Operational Preference Greenfield IRM
Risk Considerations Weather
Free-Issue Materials
Support Logistics
Free-Issue Materials
Support Logistics
Calculation of Charges Progress/Milestones Day Rate
Standard Form Contracts (LOGIC) Marine Construction Marine Construction

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Technical Insights

DSV Walkthrough


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