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Moving classification forward


At DNV GL our drive to innovate in the maritime industry goes back to our shared past. Throughout the history of both organizations we have been at the forefront of pushing ship classification and the development of class rules to ensure greater safety and efficiency forward.

The principal dimensions

Germanischer Lloyd (GL) was founded in 1867. One of the co-founders and elected board members was Mr Friedrich Schüler. As a master shipwright from Stettin-Grabow, he was an experienced shipbuilder, and soon after the foundation he was entrusted with the task of rule development. In October 1868, Mr Schüler presented the young society’s own construction rules.

Classification societies at the time determined the necessary sizes of the individual components by relying upon the often vague measurement of a ship in tonnes, but Schüler took a different path: he defined “scantling numerals” that related to the actual ship dimensions. For the first time ever, the principal dimensions of the ship – lengths, breadths and drafts – were the decisive parameters for the primary structural members. This approach made it possible to assess the strength of a ship by comparing the relationships of these values.

To lay the foundations for this system, Friedrich Schüler statistically evaluated a large number of existing ships, thus obtaining a load-related dimensioning system which took into consideration the many years of experience of the yards. This approach was extremely progressive for the time, and was rapidly adopted by other classification societies.

From tables and empirical data to engineering science

When he was appointed head of DNV in 1951, Professor Georg Vedeler, could draw upon not only his considerable talents as an engineer, but a broad range of experience in science and engineering. Just a few months after he had taken office, Vedeler presented a critical picture of the rules of classification societies at the time:

“Today, we can handle the theory of structures as complicated as ships or their component parts much better than was the case only few years ago, and we can take a much more critical look at the rules and tables”.

With this in mind, he began the process that led to DNV renewing its rules, based on the most advanced scientific and technical knowledge and adapted to the increases in vessel size the industry was experiencing. Vedeler set out a new basis for the rules: “The proposed new rules are based, to a greater extent than usual, on simple formulae for dimensioning the different components. These formulae have been established using the best possible theoretical reasoning, but must always contain an element of experience which brings the results in line with earlier practice”.

The idea of calculation using theoretically based formulae rather than tables made it possible to adopt new and untried solutions and dimensions. This represented a substantial breakthrough in terms of classification rules.

To create a better basis and wider acceptance for the new rules, Vedeler also established a technical committee composed of three key shipbuilders and steelmakers and three technical directors. He noted: “Unlike earlier changes to the construction rules, they have been circulated widely for comment on this occasion, not only among our own surveyors, but also to all Nordic shipbuilders and shipping companies with technical departments. The proposals have been seen by hundreds of technical experts, and valuable criticism has been made to us.”

The new DNV GL rules take up the challenge of these two pioneers, introducing new methodologies and innovations to move the maritime industry forward and leave it better prepared for the challenges ahead.