IT is quite a jump from marketing lobster pots in the cellar of a Hebridean pub to developing flood-proof architecture for the low-lying plains of England.

But the story of the Gael Force Group and its 49-year-old founder Stewart Graham is quite a tale, whose final chapter could yet see a billion-pound presence on Scotland's commercial landscape.

In March, many observers sat up and took notice of the company when it acquired Forres-based Varis Engineering.

Varis specialises in the design, manufacture and installation of pontoons, marinas and access bridges. It also carries out refurbishment works in distilleries and waste water treatment plants.

The deal was integral to Graham's long-term strategy of growing a business, which began with him making steel creels in his family's garage on Lewis, into one of Scotland's most important companies.

Originally from Stornoway, the son of an assistant vet and a medical secretary, his entrepreneurial instincts emerged early.

"As a teenager I had started buying old motorcycles and renovating them and trading up to other models. So I developed some engineering skills doing this and then went on to study mechanical production engineering at Lews Castle College in Stornoway.

"In the evenings and at weekends I used to do work for various people. It included repairing creels for local fishermen. But then I started to make them.

"It was a local market and being a student I used to work in a bar and take my sample creels down to the cellar every evening to show the fishermen who came in and they would give me feedback – an early piece of market research, you could say."

He was just 18 and was working at the creels in the family garage, then went on to design machinery to semi-automate the process.

But his horizons went beyond the garage doors, and in 1983 he rented a local development unit from the islands council. He was in business.

"I would probably turn out 80 creels or lobster pots a week. There are probably a couple of million round the coast of the UK, with a percentage needing replaced every year because they get lost or corrode.

"After four or five years I was employing about 10 people. We bought some land locally and built a factory."

By the late 1980s up to 1500 creels were coming off the production line every week, and Gael Force was employing about 30 to 40. However, there was a growing realisation that the company had to be about more than small cages for catching lobsters.

"I started to realise that just focusing on creels was not going to satisfy our business ambitions so we developed a range of products to complement the fishing gear – ropes, shackles, chains, chandlery, marine hardware."

There was another development. Conscious that Gael Force was restricted geographically just to having a base on Lewis, he also looked eastwards to Inverness and opened up a unit in the Highland capital's industrial estate.

"We were looking for a shop window on the mainland to allow expansion particularly into fish farming, aquaculture.

"Shellfish and finfish farming had really started to develop, and there was a market for the hardware to go with it. We bought an anchor and moorings business. As a result we could offer a service evaluating sites and then establishing fish farming businesses on them."

In the late 1990s he also bought a local operation designing and building feeding barges for the industry. Since then Gael Force has fabricated 70 feed barges for fish farming sites right round Scotland and up to the Faroes, Norway, Ireland, down to Spain.

Three big barges for the offshore renewable energy market off the west coast of the US have also just been completed.

"The biggest have been 850-tonne floating structures that hold 400 tonnes of feed. We design, build, supply and moor them.

"Those for renewable energy were 400-tonne, multi-chambered concrete floating structures which act as anchors. You float them out to the site, flood them and they go to the bottom and secure the energy device either on the seabed or the surface. If you want them back up again, you just flood them with air.

"To have a 400-tonne traditional anchor you would need enormous anchor handling vessels. Whereas with these SeaLimpets you tow them out with a relatively small boat, put and them down, but keeping an umbilical air supply on the surface."

The company moved its Inverness base from the industrial estate to Thornbush quay site on the River Ness. It was opened by round-the-world yachtswoman Dame Ellen MacArthur in 2000.

This was where his marine megastore concept was developed.

"We wanted to cater for everybody whether they had a surfboard or a tanker and built up a 20,000-product range. We now have a base in Plymouth as well as Inverness and Stornoway."

But in 2002 there was an enormous crash in the fish farming market through overproduction.

It hit Gael Force as well.

"That set us back for a while. But things have recovered and aquaculture is now at the production level it was in 2002, but this time there is a matching market. So it remains a strong and critical part of our business."

But there is also a focus on the renewable energy market and the oil and gas sector may be next for Gael Force and the specialist design, build and installation skills of its workforce.

As it is, the company has sales of £20 million and employs nearly 200 people. The expectation is it will be £50m in four to five years.

The acquisition of Varis is broadening the company's horizon. A large mooring pontoon at Birkenhead on the Mersey for offshore wind supply vessels has just been completed.

"We are also currently building a huge pontoon for the marines at Devonport, which is more like a floating dock than a pontoon."

So perhaps it is was an obvious step to look at other things that float. It comes at a time when Scottish Canals and the Canals and Rivers Trust south of the Border are encouraging people to think about living on the water, and Gael Force is working closely with these bodies.

"From our work in the fish farming industry we have developed a concept of floating homes – or restaurants, offices, any facility. We are working on a number of projects and hope to bring them to market later this year."

As well as floating homes, there are plans for "can float" homes.

"For example, in England 30% of all planning applications are for flood zones, and our concept would allow a house to be built which would look like a normal house, but when it floods it would rise up. Then when the water disappears it would sit back down again."

He believes it could be used for a development of about 200 "can float" homes, which would effectively sit in a giant sump.

"Our ambitions over 25 years is to be a world-class, billion-pound company which could leave a genuine legacy long after my lifetime."

It has not all been about work for the father-of-two. In 2009 he and his wife embarked on a two-year round the world trip.

At one point he had eight nuts and bolts, two rods and a metal plate permanently fitted into his spine after a motorcycle accident in the Malaysian jungle.

He says of the trip: "It gave me a chance to think about where we wanted to go with Gael Force."

He clearly did a lot of thinking.