Rope and Sling Specialists(RSS), a leading provider of lifting and rigging solutions, has supplied spreader beams and rigging equipment for the lifting of Acua Ocean’s USV-Pioneer, a 25-tonne autonomous unmanned surface vessel (AUSV), at Turnchapel Wharf, Plymouth.
RSS supplied a one-over-two spreader beam rig, which was used below-the-hook of a 200t capacity Liebherr LTM1200-5.1 mobile crane from the fleet of Sparrow Crane Hire Ltd. The vessel, which measures 14.2m x 9m, was recently lifted from the dockside wharf into a pontoon, which leads into Plymouth Sound.
USV-Pioneer is a dual-use solution for ocean monitoring and data collection, meaning she has been developed for both commercial and security use cases. Her moon pool enables the deployment of a modular 20ft ISO TEU payload of up to 6.5t, meaning she can deploy freight, but more specifically launch and recover subsurface systems, such as ROVs; or aerial systems, such as UAVs.
Carl Coysh, depot manager at Rope and Sling Specialists Plymouth, said: “The vessel was originally going to be lifted using some custom beams loaded onto the deck of the vessel; however, we came up with an alternative system to relieve any pressure on the vessel itself, performing a near vertical lift, which was not only safer, but more economically viable for the project.”
At the top of the rig were two 15t capacity, 12m-long roundslings, which connected to a 6.5m-long MOD34 spreader beam. Four 10t capacity, 6m-long roundslings were rigged below, where a pair of MOD12 beams were used at spans of 3.25m. To complete the system, four 15t capacity, 3m-long roundslings were attached to four 17t capacity alloy bow shackles, which made the all-important connection to the vessel.
Coysh said: “The modular spreader beam solution meant we were able to perform as close as possible to a zero-degree lift on the deck points, negating concerns for undue stress being put on those lifting points.”
Mike Tinmouth, co-founder at Acua Ocean, said: “Being able to crane lift the vessel increases speed of launch and provides alternative solutions to launching from a cradle and slipway. This enables us to operate from more locations. We considered launch solutions from the outset; however, as a build progresses, these options are refined, and we began working with solution providers, like Rope and Sling, as experts in lifting, to develop the optimum solution.”
Rope and Sling Specialists was initially contracted to complete proof load tests on RUD deck fall restraint points aboard USV-Pioneer, using a 65kN Hydrajaws portable pull tester to make sure each point was tested to 300kg. Following the successful delivery of that scope of work, in November 2024, Acua Ocean entrusted RSS with subsequent lifting tasks, including those required for sea trials, and the latest lift into the pontoon. The pick points used on that occasion were also mounted on the vessel’s deck, distanced based on the stability and centre of gravity required for a safe and stable lift.
Tinmouth added: “We have focused on developing a UK, and specifically local southwest, supply chain with 94% of the project spend in the UK. Key to that has been network and experience — our team have decades of experience in the marine sector and will most often know someone with a proven solution and experience for our needs. At this point in time, we engage suppliers, like Rope and Sling, to get their input into the solution design.”
RSS’s Coysh said: “We have assisted with lifting the vessel on numerous occasions, helping to get it in and out of the water for recent sea trials. It is extremely rewarding to be involved in a project like this. Although the equipment and rigging are our bread and butter, we are always amazed as to the incredible projects we have the privilege to support. Working alongside Acua [Ocean] has been a real pleasure. The fact that the team are so receptive to our ideas, knowledge, and expertise, makes the whole process that much more enjoyable. With more vessels planned, we can’t wait to see what the future holds.”
