Site investigation and characterisation: Why early offshore seabed mapping is critical for project success

Every offshore project begins with one critical step: understanding what lies beneath the seabed. But when decisions are based on incomplete or low-resolution data, the consequences can be costly. While construction planning and foundation procurement are often prioritised, early marine surveying is too often scoped as an afterthought.

Offshore projects demand early certainty - from permitting and route planning to foundation design and risk mitigation. That's why smarter, integrated approaches to seabed mapping, geophysical survey, geospatial data analysis and geotechnical investigation should be treated with the same rigour as offshore construction itself.

With tighter timelines, rising costs and growing scrutiny from regulators and investors, the stakes have never been higher. This blog explores why treating site investigation - across geotechnical, geophysical and geospatial solutions - as a strategic enabler, not a basic prerequisite, can unlock safety, speed and certainty across the full lifecycle of marine infrastructure.

When early insight comes too late

A robust approach to site investigation isn't just a technical formality; it's a commercial safeguard. Yet despite its impact on project outcomes, it often receives disproportionately low attention and budget.

Research funded by the Floating Offshore Wind Centre of Excellence estimates geotechnical survey costs typically sit at just £4,700 per MW, compared to turbine costs of £1.3 million per MW and structural systems at £790,000 per MW. Site investigation accounts for less than 1% of CAPEX - yet early-stage data fundamentally underpins technical feasibility, anchor selection and accurate construction scheduling.

These insights underpin permitting, routing, design, risk mitigation and procurement strategies, making them pivotal to success. Delays or incomplete data can stall permitting, derail schedules and trigger costly rework.

These impacts are especially acute in high-CAPEX environments already constrained by supply chain bottlenecks, limited vessel availability and narrow weather windows. A marginal saving at the start can become a multi-million-dollar problem later.

Rethinking site investigation for offshore certainty

Site investigation should be a coordinated process across geospatial, geophysical and geotechnical services - not isolated workstreams.

Smart sequencing of UXO surveys, bathymetry and geospatial survey - including GPS, LiDAR, 3D laser scanning, photogrammetry and dimensional control - combined with high-resolution 3D seabed mapping, ensures design decisions are based on data, not assumptions. These early insights improve design integrity, reduce rework and help avoid delays.

But it's not just about smarter sequencing, it's about safer, faster delivery too. Site investigation carries operational risk, particularly in deeper waters. Traditional methods often involve multiple mobilisations and prolonged offshore exposure. We prioritise remote deployment, intelligent tooling and modular systems.

Our approach combines autonomous underwater vehicles (AUVs), uncrewed survey vessels (USVs) and flexible platform setups with advanced digital tools like iSite, enabling teams to interpret data in real-time. For geotechnical surveys, our portable remotely operated drill (PROD) system delivers high-quality downhole data without the need for drillships - reducing cost and complexity.

Geospatial inputs provide precise location and alignment data to support accurate planning and execution. Geophysical methods map subsurface conditions to uncover subsea hazards and de-risk design. Geotechnical measurements enable safe, optimised foundation engineering. Together, they deliver the clarity and confidence needed across every stage of offshore development.

Delivering clarity, speed and control below the surface

Every confident offshore project begins with a clear understanding of the seabed. At Acteon, we treat seabed intelligence as the foundation for effective offshore delivery. Our integrated approach spans geophysical, geotechnical and geospatial solutions, supporting better decisions from early scoping through to permitting, design, construction and long-term asset monitoring.

We deploy a flexible ecosystem of modular survey platforms, suited for complex environments. Our site investigation solutions give developers the visibility they need to move faster, design with precision and reduce offshore risk - long before construction begins.