For an accurate Thruster Calculation you have write to following formula:
A: Boat Lengt x B: Boat height x C: 0,5 x D: 0,75 x E: Windpressure = Required Thrust
From Bow to Stern, write down the lenght above the water line. In this formula we take wind pressure into account. Current is excluded
Measure the height of the yacht above the waterline. Be aware the superstructure will catch wind, same as rigging. We exclude the mast itself for a Sailyacht, as otherwise the calculation would have too much variables
Often Sailyachts have a keel or Mast on with the yacht will pivot. In this case, 50% of the lateral surface of the yacht will turn into the wind, and on the other side of the pivoting point the yacht will turn away from the wind. In the calcualtion we take advantge of this phenomena. Is there no pivoting point? Or do you have a yacht with the weight in the back, you can exclude this part of the formula. The result is a larger wind catch surface in the outcome
You have just measured 2 basic dimentions: Lenght and height. Obviously the height is not everywhere the same at your yacht. If you enter the maximum height in the formula, most likely the total lateral surface would be too large. We therfore reduce the average are with -25% for those "open" areas the wind has no effect on.
In this formula we take the average windpressure from the Beaufort-Scale levels 5 and 6 into account. At these wind-pressures the wind will blow between 17 and 27 knots. Enough to make it difficult to dock your yacht.
Beaufort 5: 17-21 knots: Fresh Breeze
Beaufort 6: 22-27 knots: Strong Breeze
The average wind pressure:
Beaufort 5: 4.5Kg/m2
Beaufort 6: 7.5Kg/m2
As you see there is quite a difference in windpressure at these given levels.
You can check out the wind-pressure by adding 4.5 or 7.5kg in the calculation in order to determine which Thrust force is required for your yacht
The outcome of your calcualtion will give you a estimation of the thrust force you need.
Below we show you the 4 thrust forces we have available. In the past 10 years many yachts have been equipped with a Jet Thruser. We therefore can offer a large amount of references towards different production yachts with a Jet Thruster. Check out the Dufour and Jeanneau pages at this website to learn more.
The Official Jet Thruster Website Copyright 2010-2024
Disclaimer: CE All our products are manufactured according to CE regulations. Towards all content on this website, we keep the rights to change descriptions, graphs or statements, which are required for technical development of our Jet Thruster systems or any other reason.
Patent Pending for Jet Thruster systems