Catamaran Design - estimating speed from weight, rpm and thrust

[springer]

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

[CDBarry]

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.

[h_zwakenberg]

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

bye

Hans