Colintraive and Portavadie: Building the Berth-to-Charger Interface

Two terminals, different service arrangements

CMAL reported on 20 October that dredging at Colintraive had been completed between 12 and 15 October. Across the network at Portavadie, George Leslie Limited had mobilised on 29 September and was widening the marshalling area ahead of slipway widening. Both terminals are being adapted for the Small Vessel Replacement Programme's electric ferries. Their construction programmes use different ways of maintaining a transport connection. ^[1]

At Colintraive, the ferry is to use a secondary slipway about 50 metres south of the terminal building during the November enabling works, with the existing timetable expected to continue. At Portavadie, the published 19 October-16 November slipway closure removes the vehicle service. CMAL describes a passenger-only replacement between Portavadie Marina and Tarbert Marina. The retained landing point at Colintraive and the marina-to-marina diversion at Portavadie create different boundaries for the construction site. ^[1]

For the contractor's access plan, a working secondary slipway means separating the ferry's movements from plant and delivery routes throughout the shift. A full slipway closure instead concentrates marine work inside a defined possession, while passengers transfer elsewhere. The operating arrangement belongs beside the excavation and concrete sequence in the programme: it determines which routes the contractor can occupy and which must stay available.

The closure occupies part of a longer programme

CMAL's August scope gives Portavadie an approximately 20-week construction programme. It includes a slipway widened by about three metres, an additional marshalling lane, a new embankment, a pedestrian footway and lighting. The four-week marine closure sits within that wider programme. Releasing the slipway for vehicle traffic therefore requires an explicit division between the work needed for reopening and the landside work that can continue afterwards. ^[2]

The handovers in the last column are IMWO's proposed planning controls. For Portavadie, the reopening review should join the marine approach and slipway condition to the vehicle route, pedestrian segregation and lighting available on the return date. Outstanding embankment or marshalling work needs a continuing traffic arrangement. This gives the operator a defined usable route through an evolving site.

Concrete, ducts and maintenance space precede energisation

At Colintraive, the November civil scope comprises a plinth and maintenance platform for the cable-management system, foundations for a low-voltage switchroom and SSEN substation, and chambers, ducts and cable supports. CMAL now expects ABB's electrical works in spring 2027. Its August account had identified a February 2027 installation start under a separate contract. The October description is the current planning reference. [1, 2]

ABB's supplier account describes both the ferries' onboard distribution and propulsion equipment and its separate selection for shore connections across multiple CMAL terminals. The physical connection at the berth brings together the cable-management equipment, the shore supply and the vessel interface. Each depends on civil dimensions and access agreed before equipment installation. ^[4]

A civil handover schedule should pair each equipment foundation with the supplier's setting-out and fixing requirements, each duct with its route and pull-through provision, and the maintenance platform with the equipment's service envelope. Record the completed positions and levels before covering the route. Resolve deviations while the civil team still has access; reopening a paved cable route later can disrupt both ferry traffic and the electrical installation.

IMWO original engineering-interface diagram based on CMAL's published civil scope

The survey record connects water and land

The preparatory investigation programme announced in August 2025 included Colintraive and Portavadie alongside Tobermory and Kilchoan. CMAL listed bathymetric, utilities and topographical surveys, marine sampling, geophysics and land trial pits. It assigned the announced jack-up boreholes specifically to Tobermory and Kilchoan. These disciplines supply different parts of the port design: bed geometry, ground conditions and the location of existing services. ^[3]

For handover, join the marine survey reference to the civil setting-out reference at the terminal. The slipway toe, vessel landing geometry and shore-side equipment positions must be usable together. Keep the surveyed surface, drawing revision and any remaining local obstruction against the same workfront. This lets a later vessel-interface review identify whether a mismatch concerns the bed, the slipway or the equipment position, and direct corrective work to the right package.

A terminal ready for the arriving vessel

The March 2025 shipbuilding announcement awarded seven electric ferries to Remontowa, with the first delivery expected in 2027. The port works have their own marine, civil and electrical sequences ahead of that introduction. A terminal readiness programme needs dates for the available berth, the finished cable route, the electrical installation and the vessel-side connection checks. ^[5]

For these two ports, the immediate decisions are concrete: Colintraive must carry the completed dredging and November civil works into ABB's installation access; Portavadie must define the operational route it will release at the end of the slipway closure. A shared handover schedule should name the receiving team, the physical limits it accepts and the tests or survey records needed for that transfer. That schedule gives the vessel and terminal teams a common basis for planning their first combined trials.