Case ship design

Interview with

Jacob Norrby

Naval Architect at Stena Teknik

”This is how design affects the ship’s safety”

A large part of a ship's environmental and safety performance is determined on the drawing board. Jacob Norrby, Naval Architect at Stena Teknik, knows more.

How has the shipbuilding industry changed over the years?

“I came into the industry just when the double hull requirement was introduced in the early 90s. This was a change that had a fundamental effect on ship design. For several years now, the major focus has been on energy efficiency and a large amount of resources are also being allocated to keeping down incident levels. This also affects the conditions for ship design.”

Can you explain how?

“How energy-efficient and safe a ship will be during the 20–25 years it is in operation is largely determined by the initial design work. It is during the idea and concept phase, before the contract is signed with the shipyard, that we can influence the vessel’s performance the most. When incidents occur, they have a lot to do with handling. But the design of the ship – for example, the layout of access routes, ladders etc. on board – can both affect and facilitate safety work on board.”

What can be done on existing vessels?

“The first thing that should be done is to operate the vessel and manage all the systems as energyefficiently as possible. This is something Northern Marine Management are experts at. An example of a very cost-effective action is to operate at the optimum trim. To increase energy efficiency at lower speeds, VTA turbines can be installed. But it’s above all when the ship has had a change of operating profile – speed, cargo intake, ice class, type of cargo – that you can find technical solutions for increased energy efficiency. In these cases, you can look at main engine de-rating, a new propeller, a rudder bulb, energy recovery and so on.”

You helped develop the IMO2MAX concept. How does the ships differ from corresponding standard vessels?

We were able to spend more design time than usual on the hydrodynamic design, which meant much better fuel efficiency for the same cargo volume and speed. The vessels are optimised for IMO2 loads as they are built with more, and smaller, cargo tanks than normal. This gives a greater degree of utilisation of the cargo capacity. Cargo handling has significantly greater capacity and allows more efficient unloading and cleaning.

About Stena Teknik

Stena Teknik is a resource for all maritime-related business in the Stena Sphere. Operations include newbuilding and conversion projects, general marine technical consultation and procurement services. The company also conducts research and development in the marine sector. The work covers all types of shipping, from passenger traffic to oil tankers and rigs. Through these various responsibilities, Stena Teknik has built up an extensive knowledge bank in marine technology and naval architecture and is currently one of the leading players globally. It is a measure of the high level of competence that Stena Teknik often functions as a consultation body on different issues relating to shipbuilding technology in the EU.

Stena Teknik provides Concordia Maritime with expertise in areas that range from corrosion protection, classification and safety to more comprehensive projects related to the development and design of new ships.