BWTS Retrofit Timeline Planning and Yard Selection
Updated
A BWTS retrofit typically takes 6–12 months from feasibility study to commissioning, dominated by engineering, class approval, and equipment procurement rather than the 3–5 week physical installation. The critical path is usually the 3D scan, class-approved drawings, and equipment lead time, so these should start well ahead of the yard slot. Yard selection balances BWTS experience, capacity, location, and fit with a planned survey docking.
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Key takeaways
- A retrofit typically takes 6–12 months from feasibility to commissioning, worked backward from the ship's survey-linked compliance date.
- The physical installation is only 3–5 weeks; engineering, class approval, and procurement dominate the schedule.
- The critical path is usually the 3D scan, engineering, class drawing approval, and equipment lead time, not the on-board work.
- Equipment should be ordered as soon as the treatment flow rate is confirmed, because a late skid can idle a booked docking.
- Yard selection balances BWTS experience, capacity, location, and cost, and is often set by aligning with a planned survey docking.
- Front-loading the engineering and building 10–15 percent contingency into time and budget are the most effective schedule controls.
What Is a Realistic Overall Timeline?
From the decision to retrofit to a commissioned system, six to twelve months is a realistic window for most vessels. The physical installation is a small part of that — typically three to five weeks — while the majority is consumed by feasibility, engineering, class approval, and procurement running partly in sequence.
The timeline compresses if the technology is pre-selected, the 3D scan and drawings are completed early, and a drydock slot is already booked, and it stretches if any of those slip. Rushing the front end to save weeks usually costs more time later in rework and approval delays.
Because the deadline for D-2 compliance is tied to the ship's survey schedule, the timeline must be worked backward from the relevant survey or docking date, not forward from a convenient start, to ensure the system is commissioned before the vessel is required to comply.
What Are the Key Milestones?
The first milestone is the feasibility study, which fixes the treatment flow rate, confirms electrical margin, and identifies safety scope for the vessel type. It converts the broad options into a defined project and budget and should precede any hardware commitment.
Next come the 3D scan and detailed engineering, then class approval of the drawings, then equipment procurement and pre-fabrication of pipe spools and foundations. These can overlap — for example, ordering long-lead equipment as soon as the flow rate is fixed — but drawing approval must precede fabrication.
The final milestones are the on-board installation, class attendance, and commissioning testing under MEPC.325(75), followed by crew familiarisation and updating the ballast water management plan. Only after commissioning is the system fit for compliant service.
What Sits on the Critical Path?
The critical path is almost never the physical installation. It is usually the sequence of 3D scan, engineering, class drawing approval, and equipment lead time, any one of which can dominate depending on the project. Equipment lead times in particular can run several months for large or specialised systems.
Class approval can also be a hidden critical-path item if drawings are submitted late or require iteration. Engaging class early and submitting complete, scan-based drawings reduces approval cycles and keeps them off the critical path.
Because the front-end engineering gates everything downstream, starting the scan and design early is the highest-leverage schedule decision. A ship that scans and engineers six months before its docking arrives at the yard with approved drawings and pre-fabricated spools, ready for a short, predictable installation.
How Do You Manage Procurement Lead Times?
Equipment lead time is a major schedule driver and should be locked in as soon as the treatment flow rate is confirmed. Ordering the type-approved package early protects the yard slot, because a late-arriving skid can idle a booked docking at great cost.
Beyond the main package, filters, sensors, dosing pumps, and spare parts each carry their own lead times, and a missing minor component can hold up commissioning as surely as a missing reactor. A complete bill of materials ordered together avoids these gaps.
Stocking initial spares — filter screen elements, sensor reagents within shelf life, dosing-pump kits — at the point of commissioning avoids a ship being unable to ballast soon after install. Sea Clean AS supplies genuine Headway OceanGuard parts as an authorized agent and independent, brand-agnostic parts for other systems, and can advise on lead times and logistics.
How Do You Choose the Right Yard?
Yard selection balances several factors: demonstrated experience with BWTS retrofits, capacity and a slot that matches the schedule, geographic location relative to the ship's trading route, and cost. A yard that has done many retrofits will sequence the work efficiently and avoid rookie mistakes.
Aligning the retrofit with an already-planned special or intermediate survey docking is usually the most economical choice, because it shares mobilisation and off-hire with other work. This often dictates both the yard and the timing.
For riding-crew or alongside installations the yard question changes to a repair-berth or short-stop question, and to the availability of a controlled window for the ballast-system tie-in. The engineering and procurement discipline remains identical whichever route is chosen.
How Do You Keep the Project on Schedule?
The most effective schedule control is front-loading: scan early, engineer thoroughly, order equipment against a confirmed flow rate, and submit complete drawings to class ahead of time. Every week invested in the front end typically saves more than a week of yard time and rework.
A contingency of around 10 to 15 percent on both time and budget absorbs the ship-specific surprises a survey will surface. Building this in prevents a single clash or electrical shortfall from derailing the whole schedule.
Sea Clean AS can coordinate scanning, engineering, class liaison, procurement, and installation attendance to keep the milestones aligned. In Norway and the North Sea region attendance is 0–24 hours; elsewhere by prior arrangement. It supports OceanGuard as an authorized Headway agent and other systems on an independent, brand-agnostic basis.
Frequently asked questions
How far ahead of drydock should I start planning?
Ideally six months or more, so the 3D scan, engineering, and class drawing approval are complete and equipment is on order before the docking. Starting late risks arriving at the yard without approved drawings or with equipment still in production, which idles the slot.
What usually causes retrofit projects to run late?
Late engineering and late class submission are the common culprits, followed by equipment lead times that were not locked in early. The physical installation rarely causes delay when drawings are approved and spools are pre-fabricated; the front end is where schedules slip.
Should I always do the retrofit during a survey docking?
It is usually the most economical option because mobilisation and off-hire are shared with other docking work. If no suitable docking window aligns with the compliance deadline, an alongside or riding-crew installation can meet the date at different cost and complexity.
How much schedule contingency should I allow?
About 10–15 percent on both time and budget is prudent. A survey and 3D scan almost always reveal some ship-specific work, so contingency absorbs a piping clash or electrical shortfall without derailing the overall schedule.
Sources
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