Hiring a subsea engineering consultant: scope, questions and red flags

The trigger is usually a date. A vessel slot is on offer, an inspection has turned up something nobody likes, a supplier says the tool you need does not exist yet, or a regulator wants a removal plan. Someone has to decide what the vessel will do, and whether the plan on the table is the cheapest safe way to do it. That is the moment asset owners start looking for a subsea engineering consultant.

This note is for whoever has to buy that help: an asset director, a project manager, a procurement lead, or an investor who now owns hardware on the seabed.

When does it make sense to hire a subsea engineering consultant?

Not every subsea job needs one. Routine inspection by a contractor who knows the system can run without outside engineering. The case grows as the job gets less routine and the vessel takes a bigger share of the budget:

• Intervention on equipment never designed for it. A damaged wellhead or degraded structure, where safe access has to be engineered first.
• A campaign built around a vessel. Every problem solved on deck is paid at the vessel's rate; solved ashore, it costs far less.
• An integrity decision. A worrying inspection result needs an honest view of what the hardware can still take, from someone with no repair contract to win.
• A tool nobody sells. The fit between a bespoke tool and your equipment has to be engineered and proven ashore, not discovered on the seabed.
• Decommissioning. For many owners removal is a first, often with incomplete records, and the final cost depends on engineering done early.

If two or more of these apply, the real question is not whether to hire a subsea engineering consultant, but how early. The short answer: before the method is fixed. That means before you sign the vessel contract, before the tender for tools or services goes out, and before anything is promised to a regulator. After that, a consultant can only check a plan you are already paying for.

What does an independent consultant do that the equipment maker will not?

Many subsea engineering companies also build equipment, supply tools or operate vessels, and you will need that capacity. But the maker's solution tends to use the maker's products, and the contractor's plan tends to fill the contractor's vessel. That is not bad faith; neither is paid to ask whether another approach would need less of what they sell.

An independent consultant sells only the engineering, so it:

• compares methods across suppliers, including options that mean buying less from any one of them;
• checks the maker's equipment data against the contractor's procedures, so gaps are found on paper;
• gives you one account of the technical risk for your board, partners or regulator.

That is the job of an owner's engineer: you keep the manufacturer and the contractor, and add someone with no stake in the answer to check the plan before you pay for it.

How do you spend fewer days on an expensive vessel?

Most of what a campaign costs offshore is decided ashore. The owner's lever is what the scope asks for:

• Ask for alternatives, not only a schedule. Require the consultant to test whether steps can be combined, done from a smaller or already contracted vessel, or moved ashore.
• Ask for testing ashore of anything bespoke. Any custom tool should be fitted to your equipment and trialled on land before it sails. Make those tests a named deliverable.
• Ask which weather windows the plan really works in. Lifts and lowering to the seabed depend on the sea; the plan should say which conditions it can work in, not assume calm seas.
• Ask for the contingencies in writing before mobilisation. Agreed fallbacks mean nobody pays for standby while options are debated offshore.
• Decide whether the people who wrote the plan go offshore. People who know why the plan says what it says keep changes on board deliberate, not improvised. That is the purpose of offshore operations supervision.

Problems found on paper cost engineering hours. Problems found on the seabed cost vessel days.

The engagement "Subsea method statement" on our cases page is an example of this kind of work. A method statement sets out each step offshore, its equipment and its fallback.

What should go into the scope and the RFP?

A loose scope buys a report. A tight one buys a plan a vessel crew can execute. Whether you run a formal RFP or brief a few firms, include:

• The asset and its history: drawings, as-built records, inspection data, past interventions, and what is missing.
• The decision and its date: vessel booking, contract award, regulator submission or investment decision.
• The objective: gain access, repair, inspect, extend life or remove.
• The constraints: water depth, weather season, vessels already under contract, other operations nearby.
• The standards you work to, such as NORSOK, ISO or API, and who approves the final method.
• The deliverables: options study, method statement, tooling specification, test plan, offshore procedures.
• Presence: engineering only, or also witnessing factory tests and supervising offshore.
• Ownership of the design, the data and the tool drawings at the end.

Expect the work in stages: understand the asset, compare methods, detail the chosen one, prove the tools ashore and, if you want it, supervise offshore. Cost follows from how new the operation is, how much of the asset's history is known, bespoke tooling, the number of alternatives studied and whether you want people offshore.

Questions to ask subsea consultancy firms, and the red flags

Proposals for subsea consultancy services often read alike. These questions tell them apart:

• Does the firm, or any company in its group, sell equipment, tooling or vessel time you might end up buying?
• Who exactly will do the engineering, and will the person presenting today still be on the job when the vessel sails?
• Which alternative methods will be studied before one is recommended?
• How will the fit with the manufacturer's equipment be verified before anything goes offshore?
• What does the consultant need from you, and by when, to protect the vessel date?
• What happens to the plan if the weather window or the vessel changes?
• What does the consultant take responsibility for, and what stays with the manufacturer and the vessel contractor?
• Is each stage priced separately, so you can stop or change course after the options study?

Red flags in a proposal:

• A recommended method that uses the bidder's own equipment, with no alternatives shown.
• Senior names on the proposal and other names on the work.
• Bespoke tools with no testing ashore.
• A schedule that assumes good weather throughout.
• Deliverables that are reports rather than procedures a crew can follow.

When the proposals are in, compare them on the people named, the alternatives they commit to study and the deliverables a crew can use, not on the day rate alone. Our note on evaluating bids from the owner's side covers how to score them.

What changes when the job is decommissioning?

Removal raises the same questions with less room for error: records may be thin, the method untested, and the contract for vessels and services largely fixes what you pay. So plan the engineering and the contracting together, as part of subsea decommissioning services, before the tender goes out. The engagement "Subsea decommissioning, contracted without surprises" on our cases page is one example.

Put the same questions to us. The senior partner who scopes an engagement is the one who carries it through, with no bench of juniors behind them. If a vessel date is starting to drive your subsea decisions, send us the asset, the objective and the date, and we will tell you where the engineering should start.