When the North Sea oil and gas industry boomed into existence during the late 1960’s and early 1970s there was a problem. The only ships available to build and supply rigs were woefully inadequate. Sent from the US, they were designed for the calmer waters in the Gulf of Mexico, not the stormy North Sea.
The gap in the market was spotted by Ulstein Trading, a Norwegian shipbuilding company that up until then had made fishing boats, ferries and passenger ships. By 1974 an Ulstein engineer, Sigmund Borgundvåg, had designed the first UT 704 ship - the Stad Scotsman, creating what would become the workhorse of the offshore sector.
The UT 704’s impressive stability, speed and capacity made the design an immediate success. Some 91 UT 704’s were sold during the next ten years. It’s successor, the larger UT 705, was 18m wide and 80m long and designed to carry pipes and proved as successful.
Today, more than 200 different variants of Borgundvåg’s original design exist, by far the most variants of any ship produced, with the exception of small pleasure craft. There are more than 800 “UT Design” vessels in service or on on order. The UT ship is a familiar sight to anyone involved in the offshore industry and many outside it - a multipurpose ship that can be used to supply platforms, for construction, anchor handling, as tugs, by coastguards.
The newest variant is a well-intervention ship, designed by Borgundvåg’s son. New regulations being introduced in Norway and around the world demand that oil companies exploit ever more oil from wells. The company hopes the well-intervention ship, which can drill down into different parts of the well, will corner a new section of the offshore market.
Borgundvåg retired in in 2007 as chief designer, but still works in the design offices at Ulsteinvik, on a part-time basis. This year, Rolls-Royce, now the parent company of Ulstein, awarded Borgundvåg a lifetime achievement award. PE took the opportunity to speak to the man behind one of the most successful designs in modern shipbuilding.
Q: What inspired the UT Vessel Design?
I was born on the West coast of Norway, where there is always stormy weather. When I was ten years old my father built me a 16ft fishing boat with a 10hp engine that I was free to use on my own out at sea. When I was 14 I worked on a fishing vessel in the North Sea for two years.
So from an early age I learned the way the sea comes in and the rolling movement. It’s very important to know what way the vessel goes and the movement of the vessel.
Q: Why have UT vessels been so successful in the offshore industry?
The supply vessels coming from the Gulf of Mexico in the 1970’s had problems in the heavy sea. There was a big need for a new type of vessel. We had a lot of experience in the design of fishing vessels used in the North Sea, so we knew which design elements to focus on: higher freeboard, a large capacity for deck cargo and good stability. From the start, UT vessels have had much higher speed than other vessels and were much better in the sea.
Q: There are 200 variants on the original UT design. How do you go about designing a new variant?
They are all built on the same philosophy with the same kind of hull form. But each new one is created to be more optimised for fuel consumption and better movement.
The specific tasks a vessel has to do influences its size and arrangement. We look into the market and try and see where there is a special need for a vessel. The designs don’t always come as requests from companies, often no one initially wants a ship type. Then there is one buyer and then many. We have a strong engineering capacity and a lot of people thinking about what we can do. That lets us build up new areas of the market.
Q: Which is your favourite design?
The basic UT 704. It was the most successful anchor handler at the time, and shaped what other vessels looked like - it opened the market up. It was the first vessel my colleagues and I created.
The first UT 704 vessel - the Stad Scotsman in 1974
Q: The design tools engineers use have evolved massively since 1974. Has computer aided design and simulation software improved ship design?
There is a lot of good things about the way ships are designed today but you have to get the basics right. You can optimise for aerodynamics and hydrodynamics, so modern designs are generally better. But for some special tasks, you cannot improve the design any more than the simplest way to do it.
For example a UT 746 PSV we constructed for Statoil in 1984 is still operating today. The people in Statoil and on the rigs say it is the best vessel operating in the North Sea, that it can always go into the platform and unload and load, whatever the weather. Newer vessels come in and have to go away.
When you have an 80m wide vessel, with a capacity for 3000 tonnes on deck and it is empty, it is very stiff and rolls a lot. So you have to have very big passive stabilising tanks and that is simple. But still some new vessels have a lot of rolling because they do not take care of the basics to deal with the rolling. It’s the same with efforts to save fuel. You have to get the basics right. If the ship is rolling when you enter heavy sea, you will use a lot more fuel.
Q: What has been the most challenging ship to design?
The well-intervention vessel we developed recently was very demanding. It’s not classified as a ship, its classified as an installation, so you have to follow the rules and regulations for an installation.It’s specially made so that it can drill down up to 1000m. That influences the size and the arrangement. The engineering is very sophisticated.
The whole industry is moving further out from the shores, deeper and colder. We are moving into the Arctic waters, which is why the vessels need to be covered to deal with the icing. It’s not the iceberg which is the challenge, but the icing - the sea spray freezes onto the ship and you lose stability.
Q: Are the ships different for different regions of the world?
We’re an international company and supply all around the world. Most of the UT vessels are built outside of Norway, because there are not enough shipyards and companies in Norway to do it. The customers could be as far away as Brazil, China and Japan, and they want to support their own shipbuilding industries. But there are differences between the ships.
Take for example Brazil. There are a lot of ships designed for the North Sea working in Brazil. It’s the basic unit for offshore vessels in Brazil. They have the same arrangement as the ships in the North Sea, but meet different requirements, such as an increased capacity for synthetic crude, because they have much deeper water.
Q:What has been the most important technological advancement over the last 40 years?
The machinery system and the form of hull has changed a lot over the years, and has to be optimised for the propellers and rudders. One of the most important design drivers is to improve capacity. If you have the hull and machinery optimised for the propeller and rudders then the Dynamic Positioning and control system is very simple to implement. You have to get the basics right.
Q: How much longer will Rolls Royce Marine carry on designing and making UT Design ships?
I hope a long time. As long as we need oil and there are new reserves offshore in unchartered waters then people will use them. The future demand will be there as long as we need oil.
Q: Is there a secret to producing successful designs?
You have to be close to your customers and evolve your design with their feedback. You have to be able to discuss and listen to the customer and put it on paper and create the new vessels and equipment considering that.