Auto Steering Arm Movement Range

[Fanie]

On an auto steering arm, what should the movement range be ? 300mm ?

How much force is expected on this arm... 20 kg's ?

[Guest62110524]

depends on your boat speed, rudder size, rudder balence, tiller arm length,
working backwards(which is no help) you would need, a pressure gauge in line, ram size and cyl size
from there you would know how much force was needed to shift rudder

shorten tiller arm , smaller distance travelled by ram, and more force needed
all the companies that market these things, give you all you need know, they just need rudder size boat type, max speed

[Fanie]

I'm referring to an electro mechanical auto steering

What is required that will work on most sailing boats ? Some of the ones you can buy looks very flimsy to me.