[TG] [TG11] SPX-5 Virtual Rudder Indicator Shows Rudder Hard Over

[Tom - Raymarine - Moderator]

Hi Dave,

This is definitely not an ST6002 fault. I don't know why this would have been replaced before, but that's akin to replacing the keyboard on your computer in order to try to fix a problem with your email. The ST6002 is purely a display, it has no intelligence - all of the course-keeping decisions happen within the SPX. In my experience though, when dealers don't know how to diagnose or fix an issue, they tend to replace 'something' in order to get the job off their desk, and very often (we know this from all of the no-fault-found warranty returns we receive) they replace something that is working perfectly.

As I say, I've never (in 20 years of Raymarine support) come across a situation where a pilot had correct heading data and 'knew' that it was off course to starboard (and also had either no rudder or correct rudder data), but still applied starboard course corrections (exception: when either drive or rudder operating sense are inverted so that when the pilot tries to drive to port, it sees heading or rudder data for a starboard turn and applies more helm to correct until hard-over.) In my experience this means one of 3 things:

• the pilot has a failure type that I've never seen or heard of before
• the heading data is not correct - I don't think that's the case because of the off-course alarm, but in intransigent cases we have to question every assumption
• the problem is actually in the drive, so that it looks as if it's driving port-starboard but is in fact doing something like driving port but then slipping back starboard due to an internal problem in the drive and resistance on the helm
  

We can still do useful tests with the boat on the hard if you want to, without waiting until May? I'd start by making positive port-starboard course changes on the pilot display whilst measuring drive output voltage and looking at the wheel movement, and apply load (drag) to the wheel and see how it copes.

If the problem is the first of the 3 above and the pilot really is making incorrect course changes based on correct sensor data then it will need to be replaced (with an EV pilot unless you can find a pre-loved SPX5), but I don't think the SPX is broken.

Tom