Table of Offsets for the Oseberg Ship

Hi, are you looking for plans to build a Viking Ship? Well, here is a start. I have put together this page from material available from the University Of Oslo. They have more material available, of course, in what is known as "Universitetets Oldsaksamling".

What you see here is a table of offsets which is 90% of what you need to create your own plans of a Viking Ship with lines like the Oseberg Ship.

If you are new to boat building, you may be excused for thinking that this sure doesn't look like any plans you have ever seen before for other building projects. And right you are. The thing about boats is that they have almost no right angles whatsoever. Everything is a curve fitting into another curve or two or three or... Well, you know what I mean.

For as long as man has gone to sea, he has built boats without formal plans. Mostly, without even a table of offsets. Skilled shipwright built their boats from memory and integrated their own improvements and maybe the wishes of the owner. The builders could be stubborn old coots and it could take some convincing to introduce a new feature.

Be that as it may, today we usually need a little more firm starting point. This starting point is preferably a table of offsets. What is a table of offsets? It is simply a table giving vital measurements according to a standard way of measuring the dimensions of a hull.

The standard method goes more or less as follows:

1. Divide the hull from stem to stern into a fixed number of evenly spaced sections or stations. The number of stations varies with the length of the ship, but even a large hull like The Oseberg can get away with as little as 10 stations. If you need stations at other distances than those in the table of offsets, you simply lay them out yourself after you have lofted the original offsets. Often, a table of offsets will give you measures at half sections in the stem and stern to give you a more accurate template to lay out the particular lines in these areas. The stem and stern are seldom, if ever, symmetrical (i.e., they are different shapes).
2. Establish a baseline through the middle of the ship at some fixed distance from the keel at one particular station. In the Oseberg table, this station is L2. The baseline is set at 240mm above underside of keel.
3. Set a distance between waterlines, e.g., 200 mm for the Oseberg. Think of a waterline as the contour of a thin, horizontal slice of the hull. The waterlines are measured vertically up each set distance, e.g., each 200mm and a measure is taken from the center line horizontally to the inside of the hull.
4. From the inside of the hull at the waterline mark, measure the vertical distance to underside of keel, the barkholt and to the rail. The underside of the keel will typically be below, so the measure comes out negative, e.g., -35 at L1 for the Oseberg Ship. Note: At station L1/2, the underside of the Oseberg keel is 395mm above the baseline because the stem has a very large seep up and out of the water.

That's all there is to it. From these measurements, you can lay out the waterlines and the side view of the ship. This process is called lofting and is what gives you a full size set of lines from which you can make templates for the station moulds, the keel and the individual planks.

Here is the complete table of offsets.