Catamaran Design - estimating speed from weight, rpm and thrust

Hi everyone

I am new to this forum and hoping to get some help.

I am in the process of designing an unmanned catamaran. The hull is almost complete and thrusters are going to be installed soon.

I want to do some tests on the thrusters before their installation to calculate the thrust produced at a given rpm. This will be carried out on a stationary paltform.

Suppose I have the the thrust and rpm information together with the vessel weight, is there anyway I can estimate the speed of the catamaran in the water? Are there any other parameters need to be identified?

Does anyone know anything about the bollard condition?

Thanks

 

You will be testing in the bollard condition, that is defined as zero speed (tied to a bollard). The thrust will generally fall off with speed. The resistance will increase depending on hull shape, weight, separation, etc.

Estimating resistance accurately is not a trivial problem, and there are many approaches that you will find referred to in strings here.

The speed at which thrust equals resitance, accounting for propeller / hull interaction effects, is the speed.

 

Leo Lazauskas' software called 'Michlet' could help you - see http://www.cyberiad.net/michlet.htm

bye

Hans