The barges still plying the River Hull that pay homage to the city's centuries-old trade in rapeseed oil

Their barges can be seen just about every day on every high tide on the River Hull.

Mainmast’s Tanker Barge Swinderby loaded with 450 tonnes of edible oils from Cargill's River Hull plant, approaching Drypool Bridge, en route to King George Dock, Hull Picture: Dan Longbottom

But few people will realise what work the green and yellow Mainmast barges do – or that the industry they play an integral part in has been part of the city’s life for centuries.

The Hull-based tank barge operator celebrates 20 years this year.

Sign up to our daily newsletter

The i newsletter cut through the noise

Although people may think the yellow fields of oilseed rape round the city are a modern invention, but the crop first started to be imported from the 1500s, mostly from Germany and the Low Countries. Hull is still one of the main centres for oil seed crushing in the country along with Liverpool and London.

Exol Pride heading up the River Don section of the Sheffield and South Yorkshire Navigation Picture: Maik Brown

Mainmast has two barges dedicated to carrying rapeseed oil from the distinctive 1912 built Isis Oil Mills operated by Cargill on Stoneferry to King George Dock where it goes either to the AAK refinery, for export abroad or use in biodiesel or fish farms. Once refined, it has a wide range of uses – from frying crisps to going into margarines and spreads.

Journeys are also made further up the river to the Croda processing site on Oak Road.

Last year the company carried about 130,000 tonnes in Hull – equivalent to taking more than 9,000 HGV journeys off the city’s roads.

“Our barges carry between 350 and 500 tonnes each trip and on average we move over 2,500 tonnes a week,” said Andy Sanders, director of Mainmast. “That takes a lot of road congestion out of the centre of Hull.”

Mainmast also operate barges in Liverpool and the barge Exol Pride, formerly JH Whitaker’s Humber Pride, which was making at least one 400-tonne delivery per week of lubricating oils from Hull to Exol Lubricants Blending Plant at Rotherham until the breach in the Aire and Calder Navigation last December.

That ended what Mr Sanders says was a “particularly challenging” year.

Recent decades have seen the number of working wharves on the River Hull decline and that has led to silting up and neglect of banks and quaysides.

Flood defences built by the Environment Agency along the river over the past two years has seen the river blocked at times and heavy disruption to river traffic.

As well as the recent breach on the Aire and Calder Navigation which has stopped commercial traffic until it reopens – possibly in mid August, the Canal and River Trust has also had to make major repairs to the Figure of Three Locks on the Calder and Hebble Navigation, as a result of damage from Storm Ciara.

However there is potential for growth – Exol Lubricants have been looking to increase their deliveries to two barges a week between Hull and Rotherham.

Mainmast continues to invest in crew and recently employed an extra captain.

“It is a commitment from us at a time when the business is disrupted, but we are taking a long term view,” said Mr Sanders. “We can’t afford to lose the crew – they are such a scarce resource now.

“The difficulty we have on the internal waterways is there is not a massive pool of qualified captains, and a lot who used to work on barges are heading towards retirement, so in addition to taking on fully qualified crew we are looking at supporting and developing skills of younger crew in order to safeguard the future of our industry.”