Re-scaling Billing Boats

[Kristian Sigvardsen]

If a Billing boat model has been scaled down from the original, can a model be scaled up to a small personal craft size and keep it's proper sailing stabilities?
For example if their viking boat model measurements have been taken from the original, then can the model measurements be brought up to a 3 -4 meter size?

[Todd Bradshaw]

Probably not too well, unless you can lie on the floor and keep your center of gravity down where that of a scaled-sized crew would be. At some point, a scaled-up viking ship model sort of becomes a canoe. Most 12' canoes have a beam of 24"-36" or more. The wide ones are pretty stable, but slow, the narrow ones are pretty responsive but have less stability, even with the paddler sitting on the floor. They would be awfully tender under sailpower.

10'-12' sailing dinghies need to be pretty beamy to be stable and even then, usually don't have the kind of steady stability that big boats have. My 12' Mini 12-Meter sails like a big boat, but it carries better than 300 lbs. of lead shot in a hollow fin-keel to achieve that kind of ride. The hull was designed to be much more bulbous than an accurately scaled-up model of a real 12 would be to keep all that lead and me from just sinking.

I think you could probably maintain the general Viking profile (or at least flavor - you might need to add some freeboard), but I think you'll need to add quite a bit of beam for buoyancy and stability. It might also just be better to spend your efforts building some kind of small Faering instead. You might end-up with a more useful and practical boat and it could still be beautiful and show it's Viking heritage.

[PugetSound]

Kristian,
Sure, you can scale a model back up to the FULL SIZE original boat and expect it to retain its architectural characteristics, but if you scale the model up to something less than the full size original then the New Model will maintain the intended sailing characteristics only for a SCALED LOAD (and only in a scaled environment). In other words, for a scale model to behave like the full size version it has to be loaded appropriately -i.e. a scale model load! Also, this doesn't account for the fact that you cannot adjust the scale of the water (water density plays a part in the proper behavior of scale models). There are ways of adjusting for the water modeling factor but you really don't want to go there.

If you really want to build a small one or two person version of a larger boat (say a Viking longboat), my advice is to employ a Naval Architect/Yacht Designer who can make appropriate adjustments in the design (see Mr. Bradshaw's response).