Drill Ship: Functions, Features & Safety

Updated on 8 Jan 2026

Offshore projects demand big investments, tight timelines and constant adaptability as conditions change. If you work in marine operations, insurance planning or offshore logistics, understanding how each offshore unit functions can directly impact safety and cost. A drill ship is especially important because it can move, position itself precisely and work in deep waters where fixed rigs cannot. Knowing what it does helps you assess risks better, plan operations with confidence and make decisions that truly support your project’s success.

What is a drill ship?

A drill ship is a specialised marine vessel designed to drill exploratory and production wells in the ocean. It can travel independently between drilling sites, making it ideal for deep-water locations where fixed rigs cannot operate.

Although it may resemble a cargo ship, its structure supports complex offshore drilling. It houses essential drilling equipment, stability and positioning systems, seabed-connection tools, work areas, storage zones and technical rooms. Its mobility and ability to operate in harsh marine conditions make it crucial for safely accessing underwater oil and gas reserves.

How does a drill ship work?

A drill ship functions as a mobile offshore drilling unit. It travels to the drilling site using its own propulsion system and uses dynamic positioning or mooring anchors to hold itself in place. Thrusters continuously adjust to counter waves, wind and currents.

Once stable, the subsea blowout preventer (BOP) is installed on the seabed above the wellhead, and a marine riser connects the ship to the BOP stack to create a secure passage for drill pipe, drilling fluids and control signals.

Drilling then begins as the drill pipes and tools are lowered to the ocean floor, the drill bit cuts through rock layers and drilling mud cools the equipment, balances pressure and removes debris.

Throughout the process, sensors monitor sea conditions and adjust the vessel’s position to protect equipment. Because the ship is self-propelled, it can move easily between sites, making offshore operations more efficient and reducing reliance on support vessels.

Key features of a drill ship

Drill vessels are equipped with systems that allow them to operate safely and efficiently in deep waters. Some key features are:

• Moon pool: A protected opening in the hull that lets drill pipes, ROVs and tools pass safely into the water, shielded from waves and weather.
• Drilling derrick: Houses the top drive and automated pipe-handling systems used for deep-water drilling.
• Dynamic positioning system: A computer-controlled system using GPS, sensors and multiple thrusters to hold the vessel in place. Drill ships usually use DP2 or DP3 systems with redundancy for safety.
• Riser system: A series of large-diameter pipes that connect the drill ship to the subsea BOP stack installed above the wellhead.
• Mooring system: It is used in shallower areas to keep the vessel fixed with multiple anchors.
• Helipad: This allows for the easy movement of crew members, equipment and emergency support.
• Living and storage areas: They comprise cabins, control rooms and storage that support long-term offshore operations.

Types of drill ships

Different drill ships are used based on location, depth and operational needs. The most common types are:

• Conventional drill ships: They come with basic dynamic positioning and standard drilling systems for deep-water work.
• Ultra-deep water drill ships: Designed for water depths beyond ~3,000 metres (about 10,000 feet).
• Sixth and seventh-generation drill ships: Industry shorthand for newer vessels with dual-activity systems, higher redundancy and deeper-water capability (not a formal global standard).
• Dual activity drill ships: These are capable of performing two drilling tasks at the same time for faster operations.
• Hybrid drill ships: They combine features of semi-submersibles and drill ships to improve stability in harsh sea conditions.
• Purpose-built and converted drill ships: Purpose-built ships are made specifically for drilling, whereas converted ships are older vessels modified for drilling requirements.

Safety measures followed on drill ships

Drill ships follow strict safety protocols to protect the crew and equipment. Before operations begin, dynamic positioning systems are tested to ensure the vessel can stay steady, and motion-compensation tools help manage wave movement during drilling. Remotely Operated Vehicles (ROVs) inspect and operate subsea equipment, including the blowout preventer (BOP), which is installed on the seabed to control well pressure and seal the well in emergencies.

The crew regularly participates in fire, evacuation and oil-spill response drills. Onboard sensors monitor weather and sea conditions for early warnings, and all personnel must use protective gear such as helmets, gloves and fire-resistant clothing. Medical rooms with trained staff ensure quick response during emergencies.

Conclusion

Drill ships make offshore exploration possible in places where traditional rigs cannot reach, but their complexity also means every decision carries operational, financial and environmental consequences. For anyone involved in these projects, understanding how these vessels work is more than technical knowledge; it’s a foundation for safer planning, better risk assessment and stronger compliance with strict offshore regulations.

When movements, equipment or crew need added protection, choosing the right marine insurance policy, including single-transit cover when required, ensures operations remain resilient in a challenging offshore environment.

FAQs

• What makes drill ships essential for offshore exploration?

Drill ships enable access to ultra-deepwater oil and gas reserves that are impossible to reach with fixed rigs. Their mobility and advanced systems also reduce the need for multiple support vessels, saving time and cost.

• How do drill ships manage emergencies at sea?

They are equipped with blowout preventers (BOPs), emergency disconnect systems and ROVs for subsea intervention. Crew undergoes regular safety drills, and sensors continuously monitor sea and weather conditions.

• What role does technology play in modern drill ships?

Modern drill ships use top drives, automated pipe-handling, dual-activity systems and high-class dynamic positioning to improve drilling efficiency, safety and accuracy in challenging offshore conditions.

• How does a drill ship impact project planning and risk management?

Understanding a drill ship’s capabilities helps operators plan operations, estimate costs and manage environmental and safety risks. Insurance and contingency planning are tailored to the vessel’s mobility, depth range and operational complexity.

Disclaimer: The information provided in this blog is for educational and informational purposes only. It may contain outdated data and information regarding the topic featured in the article. It is advised to verify the currency and relevance of the data and information before taking any major steps. ICICI Lombard is not liable for any inaccuracies or consequences resulting from the use of this outdated information.