Raymarine AP EV400 Overshoot on routes

[BigAl.NZ]

Hi,

We have a Raymarine EV400 on a 38 foot / 15T yacht.

It performs awesomely when adjusting course with the +/- 1 and 10 increments and is deadly accurate.

However when it has to steer a route, even with minor changes in heading between the waypoints, it overshoots more than I would think is acceptable.

To be fair it has always done this since we installed it, its not a new problem.

I have tried to change from aggressive steering, to cruising, but that made no difference.

As an example, see in the video below how the blue line (COG) goes well past the waypoint (sorry about the narrative in the background).

The AP is connected to a electrical motor which drives a hydraulic linear arm, which is rather old and was connected to the previous AP.

Other than this overshoot the whole system works very well.

Any ideas how to fix it?

Cheers

Al

https://photos.app.goo.gl/VonwQ6ZNUeZd9wx57

[BigAl.NZ]

It sounds very much like this issue here :

correcting autopilot overshoot

If I understand this thread correctly what Raymarine are saying is that when it goes to steer to the next waypont, it first gets the boat "into" the corridor between waypoints, IF the arrival radius is too small then the boat will overshoot and need to get back into the corridor to get back on the path.

Thus...increase the arrival radius to buy a bit more time, and using cruising mode which I think increases the width of the corridor between waypoints?

AG

[smac999]

I'm not sure what the 400 has as it's all auto setup. But I imagine there must still be manual settings for ruder, counter rudder, gain etc. This is how you fix it.

[BigAl.NZ]

Originally Posted by smac999

I'm not sure what the 400 has as it's all auto setup. But I imagine there must still be manual settings for ruder, counter rudder, gain etc. This is how you fix it.

Well I thought thats what the 3 modes did (in a coarse way) Performance, Leisiure, Cruising - I tried all 3 modes and same problem.

[vanderd]

My RayMarine system which has been installed for about a year does the same thing. While at the Miami Boat Show a few days ago I spoke with RayMarine. They suggested checking the “hard over time” if it’s set longer than the actual time it takes the pump to travel then it overshoots. I haven’t had a chance to check but I’ll pass it on for what its worth.

[CarinaPDX]

My earliest Autohelm (later RayMarine) autopilots steered very well, but beginning with the 4000T/GP it was unstable and wouldn't steer straight. I was in England at the time so talked to the RM engineers, and even had a modified firmware installed (which didn't solve the problem). My take is that in trying to improve performance for modern light, fast boats they lost stability for small, heavy, slower boats. I couldn't even trust the AP in the Kiel Canal. Pelagic here I come...


Greg