# Scale models

Scale models for engineering studies can help evaluate seastead designs.

Basically if you scale dimensions down by 25 and speed down by 5 things will happen at the same relative fraction of hull speed. If wave heights and wave lengths are scaled by 25 then wave speeds are also down by 5. So things work out well. However, in the model everything is happening 5 times faster. So if you see something tip back and forth every 2 seconds in the model it would be every 10 seconds in the full sized version. A 10 knott wind in the model is like a 50 knott wind in full scale. The important relationship between 25 and 5 is that 5 is the square-root of 25. Works for other numbers with this important relationship too.

If you want to do 1:25 scale model of 8 foot waves with a period of 10 seconds then waves in the model should be 4 inches high with a period of 2 seconds. Model waves 1 foot high correspond to 25 foot high real waves. Probably most modeling will be using between 4 inch and 1 foot waves.

Mass scales with the cube of the dimension, so at 1:25 scale the mass in full scale prototype is 15,625 times larger than in a model. So if a model has 20 lbs of ballast the full scale will have 312,500 lbs of ballast.

## External links on scale modeling

* Wikipedia Similitude (model) * Wikipedia Similitude of ship models * Wikipedia Ship model basin * Wikipedia Response amplitude operator * Wikipedia Port Revel Shiphandling Training Centre

## Related

* Wikipedia Ship motions * Wikipedia Seakeeping * Wikipedia Ship stability * Vince Cate Models

## Computer modeling

* Ultramarine on boat modeling *blender