Wilkie Engineering, of Newburgh, Aberdeenshire, has taken a 10% stake in Aberdeen firm Oasis Marine Power (OMP).
The value of the deal, which leaves Jebb Smith, owning 90% of OMP after offloading one-tenth of the shares, was undisclosed.
Wilkie has a total of 17 employees and there are currently six people working for Jebb Smith’s OMP business.
The two companies will work in collaboration to deliver the Oasis Power Buoy – a pioneering offshore charging unit that allows hybrid and electric vessels to recharge at sea.
OMP managing director George Smith and some of his team recently visited Wilkie to witness final testing of the buoy before sea trials later this month.
Wilkie managing director Russel Davies said: “This is a strategically important move for Wilkie Engineering as we diversify into the renewable sector.
“We look forward to working hand-in-hand with George and his team in developing the Oasis Power Buoy and future products.”
Mr Smith said: “We are thrilled to have Wilkie Engineering as both our manufacturers and investors.
“It was of utmost importance to have a local company on board that we could fully trust to deliver the quality engineering required for the Oasis Power Buoy.
“Wilkie also shares our aspirations for creating a new generation of products that will reduce carbon emissions and have longevity in the marine sector.”
The Oasis Power Buoy harnesses energy directly from wind turbines, providing a zero-emission energy source.
It functions as both an offshore mooring and charging point.
Family-owned Wilkie has been on the go for around 45 years.
Launched in 1976, with one employee, it started life as a blacksmith and moved onto its current manufacturing site about 10 years ago.
Today, the firm offers specialist engineering, machining and fabrication services to major oil and gas operators and their contractors.
It has clients across the oil and gas, remotely-operated vehicle, oceanographic, waste management, wider mine, aerospace and motorsport sectors.
Cults-based Jebb Smith is a specialist in marine engineering design.
It announced the launch of its OMP subsidiary earlier this year, with the aim being to focus the new venture on the renewable energy market.
Meanwhile, Jebb Smith was recently awarded a share of £120,800 funding to lead the development of a hydrogen offshore transfer system (Hots).
The work will define the Hots’ required specifications and complete the product’s design and marine engineering.
Jebb Smith is working on the project with Edinburgh-based Logan Energy and the Centre of Excellence for Low Carbon and Fuel Cell Technologies.
Their £39,900 funding is part of the Clean Maritime Demonstration Competition, which supports the development of innovative technology to bring zero-emission ships into commercial operation by 2025.
The competition is being run by the Department for Transport, in partnership with the Innovate UK agency.
Transport Secretary Grant Shapps announced the funding at a London International Shipping Week event in September.
Other current projects for Jebb Smith include the development of a safe and efficient hydrogen offshore transfer system.