The Art & Engineering of Converting a Drillship into an Offshore Wind Installation Vessel

What motivated Transocean to enter the offshore wind sector and convert some of its drilling vessels into wind foundation installation vessels, especially during the times of high dayrates being secured by offshore oil and gas drilling vessels?

Transocean continuously evaluates ways to leverage its core competencies and assets. We can convert one or more vessels to offshore wind installation vessels while further augmenting our strong offshore expertise.

Of course, our shareholders expect that we will pursue business opportunities that are accretive to the value of the company, so we will always consider the various options we have available to us and only make investments in those that generate the appropriate financial returns.

What progress has been made since April? What are the next steps in the formation of the joint venture?

We continue to evaluate the offshore wind foundation installation market and engage potential customers.

Could you elaborate on the process of converting offshore drilling vessels into wind foundation installation platforms? What challenges do you anticipate during this conversion?

The conversion of a drillship to a Fixed Foundation Installation Vessel (FFIV) is quite complex and takes diligent planning and engineering. The process can be broken into four key steps:

• Remove the drilling equipment, including the drilling derrick and thrusters.

• Mobilize the vessel to a dry dock facility for the main hull modification work scope, which includes adding 8-meter-wide sponsons on either side of the ship that run nearly the entire length of the vessel. This modification adds sufficient deck space, improves the vessel's stability, and strengthens the deck. This is required for the vessel to be operationally efficient as a FFIV. In addition to the hull modification, a new anti-heeling system is installed, and the existing water ballast system is upgraded to enable the vessel to carry and install the extremely large monopiles, which could be more than 3,000 tons each. Our design would hold a maximum of six monopiles at a time.

• Add energy-efficient features to reduce the vessel's emissions.

• Install state-of-the-art equipment for handling and installing the wind turbine foundations.

What significant upgrades to the deck and the hull are required for a drillship to become an offshore wind installation vessel?

We have designed the vessel to tackle the largest foundations. It would be capable of handling a 3,500-ton monopile, 12+ meters in diameter and 120+ meters in length. To handle such large monopiles, we need a very large crane. We have selected a crane with a lifting capacity of 5,200 tons.

Do you already know which Transocean drilling vessels exactly are conversion candidates?

We have identified a class of vessels for the basic design and front-end engineering. However, this is flexible.

Can you talk about the planned deck space? Is it limited to the current drillship size, can it be expanded? How many of the currently biggest monopiles will you be able to load onboard?

When designing the vessel, multiple factors need to be considered: deck space, deadweight carrying capacity, stability, maneuverability, efficiency, and vessel speed. All of these factors were carefully considered and applied. We will be configured to carry six monopiles at a time.

In your April 2023 announcement, the company said that the converted vessels would have "efficiency-enhancing operating features." Could you elaborate on some of these features and how they will optimize the installation process?

We plan to install the following energy-saving and emission-reduction features:

• Energy Storage System to reduce emissions by capturing and storing excess power for future use

• IMO Tier 3 compliance and lower emissions, uses ultra-low-sulfur diesel, NOx reduction by up to 95%, CO2 reduction by 20%+

• Dual-fuel ready