Qgroundcontrol how to change speed of the boat?

Hi everyone!

At the moment I’m very bussy with my final paper for school. I need to run a simulation for which I use PX4 in Headlessmode (no Gazebo only with QGroundControll).

I am using the boat vehicle but I can’t seem to change the driving speed. It is always 1 m/s.
The things I have already tried to fix it:
-looking in QGroundControl in the vehicle setup. I’ve changed a lot of parameters but nothing helped.
-Chanding the boat data in the boat.sdf.jinja file. I did change and check nearly all the numbers in this but nothing really worked.
The only time it went faster was when I changed the Input_scaling for only 1 engine. This made the boat faster but ofcourse it only spinned. When changed for both it went back to the normal speed.

Is there a way to easily change the driving speed?

I hope to hear from you guys soon!

Yours sincerily,