River Arun

Working on one of the fastest flowing rivers in England was always going to have its challenges. The River Arun is tidal for over twenty-five miles inland and the tide can run at nearly seven miles per hour.

Tasked with providing a safe working platform for survey work to take place, reaching the underside of Ford railway bridge was problematic enough. The added fact that it also has a tidal range between three and five metres, accessing the bridge structure was not going to be easy.

The current bridge was built in 1938, replacing a previous telescopic opening bridge from 1862, built upon the existing Victorian brickwork abutments. Due to the fact the river is so fast flowing these bridge supports are protected by a substantial timber structure that funnels river traffic through the middle span and prevents damage from wayward vessels.

The timeline for the project was just three weeks for the team to survey all five spans of the rail bridge.

Due to the tidal constraints and the challenging river conditions, it was decided to send two boats. Rebel Defender, a 6-metre aluminium workboat powered by a 70HP outboard engine would provide sufficient power to manoeuvre and position the pontoons in the fast-flowing tidal stream. Rebel Three a 4-metre Rigiflex workboat would operate within and around the timber fender structure and serve as a fast-water rescue boat if required.

Four modular pontoon sections were assembled at our Fishbourne yard and transported to site by crane trailer together with the Rigiflex workboat. Rebel Defender was transported separately on its own trailer.

Upon arrival on site, both vessels were launched from a nearby slipway and secured to a convenient pontoon berth. The modular pontoon sections were then launched and assembled on the water to form two separate working platforms fitted with edge protection.

The pontoons were specifically designed to fit between the vertical supports of the timber fendering system and, when tidal levels permitted, could be taken over the horizontal waling members to provide safe access to the work area. Once in position, our team secured the pontoons using long mooring lines.

The surveyors were then collected from the riverbank and ferried to the pontoons. Due to the substantial tidal range, they worked from mobile access towers that could be quickly adapted, dismantled, and reassembled in response to changing tidal conditions. The towers were secured to strong points incorporated into the pontoon decks using ratchet straps.

The availability of two separate pontoons enabled two survey teams to work simultaneously in different areas of the structure when required, increasing operational efficiency and reducing the overall survey duration.

Despite the challenging river conditions and significant tidal range, our experienced marine team successfully delivered a safe and effective access solution, enabling the survey works to be completed efficiently and without disruption.

Whether working in tidal waters, rivers, ports, or coastal environments, Rebel Marine provides safe, practical, and dependable marine access solutions.

Contact Rebel Marine to discuss your project requirements.