A DTS Is the First Real Engineering Step

A Desk Top Study (DTS) is not just a desktop collection of charts and public information. For a subsea cable project, it is the first structured engineering review of the route, landing options, seabed risk, human activity, environmental constraints and likely survey requirements.

A good DTS helps the owner make early decisions before spending money on marine survey, permits, installation planning or cable procurement. It identifies where the project is simple, where the route is exposed to risk, and where the next stage needs better data.

For telecommunications, power, renewable energy, interconnector and island connectivity projects, the DTS usually develops the Survey Cable Reference Route (SCRR). This route is then refined during the marine route survey and later converted into the final Route Position List (RPL), burial plan, protection strategy and installation methodology.

The ICPC Guidance: Recommendation No. 9

The industry reference normally used for submarine cable desktop studies is ICPC Recommendation No. 9, Minimum Technical Requirements for a Desktop Study. The current ICPC listing identifies it as Recommendation 9-5B. It is guidance, not a substitute for project-specific engineering judgement, but it gives the right framework for what a DTS should consider.

The key point is simple: the DTS and the marine route survey should work together to identify the safest and most technically viable route. The DTS should not be written after the route is already fixed. It should challenge the route early, compare alternatives, and document why the preferred option is practical.

What a Professional DTS Should Review

A professional DTS brings together multiple information streams and converts them into route decisions. The strongest studies do not only describe the area; they explain what each constraint means for cable safety, survey scope, burial feasibility and installation risk.

• Bathymetry and seabed morphology: water depth, slopes, channels, escarpments, reefs, ridges, shoals and potential free-span risk.
• Geology and shallow stratigraphy: sediment type, rock exposure, carbonate risk, mobile seabed, slope instability and expected burial behaviour.
• Metocean and oceanography: winds, waves, currents, tides, cyclone exposure, monsoon seasonality and workable marine survey or installation windows.
• Human activity: AIS traffic, anchorages, fishing intensity, trawling, ports, dredging areas, military zones, tourism areas and local vessel activity.
• Existing infrastructure: submarine cables, pipelines, outfalls, protected assets, crossings, proximity constraints and third-party interface requirements.
• Environmental and cultural constraints: marine parks, sensitive habitats, heritage areas, protected species, coastal access and permitting considerations.
• Landing point constraints: beach morphology, reef flats, surf zone, nearshore gradients, land access, HDD feasibility, beach manholes and shore-end protection.
• Survey planning: recommended corridor width, sensor suite, geotechnical ground-truthing, landfall survey, UXO or magnetometer requirements and data gaps.

From Data to Route Decisions

The value of a DTS is not the number of pages. The value is the clarity of the decisions it supports. A cable owner should be able to read the report and understand which route option is preferred, what risk remains, what survey data is required, and what issues may affect permitting, construction or long-term maintenance.

Typical DTS Outputs

Why the DTS Matters Before Survey

Skipping the DTS can make the marine survey more expensive and less useful. Survey vessels may be sent into a corridor with avoidable routing problems, landfall risk, infrastructure conflicts or poor installation conditions.

A well-prepared DTS gives the survey contractor a better starting route, tells the client where uncertainty remains, and helps the project team plan the correct sensors, survey corridor, geotechnical locations and deliverables before mobilisation.

For cable systems, the early route choice can affect the full life of the asset: installation cost, repair access, cable protection, exposure to fishing and anchoring, crossing complexity, permitting delay and long-term reliability.

QOffshore Approach

QOffshore prepares DTS and route review work from a survey and installation-risk perspective. The focus is not only to produce a report, but to develop a practical route basis that can be used by the client, survey contractor, installer, permitting team and engineers.

Our DTS workflow combines hydrographic, geophysical, geotechnical, AIS, metocean, environmental, infrastructure and landfall information into a route-risk view. We then convert that into practical outputs: route options, SCRR development, data-gap analysis, survey scope, crossing review, burial and protection considerations, and clear recommendations for the next project stage.

Key Takeaways

• A DTS is the first structured engineering and route-risk review for a subsea cable project.
• ICPC Recommendation No. 9 is the recognised industry guidance for minimum DTS requirements.
• The DTS should define and challenge the Survey Cable Reference Route before marine survey mobilisation.
• The best DTS converts existing information into route decisions, survey requirements and risk controls.
• For cable owners and developers, a strong DTS can reduce uncertainty before survey, permitting, installation and protection planning.

Industry note: ICPC Recommendation No. 9 is referenced as industry guidance for Desktop Studies. Project requirements, local regulations and client specifications should always be confirmed for each cable system.