Raymarine autopilot SPX-10 does not keep course downwind

[Olianta]

Hi,

I have a light displacement 37' performance cruiser with tiller steering and Raymarine SPX 10 autopilot. During the last ARC we (a crew of three) did hand steering all the time on a 15 day + downwind passage. Our sail combination was main + spinnaker 60% of the time and main plus poled out jib rest of the time. We found out that the autopilot, though set in performance mode, could not keep straight course and did have a mind of its own. Since this was our first time prolonged fast ocean sailing, my question is whether this is normal, i.e. whether we expect too much from the autopilot on this course with such sail combination. Even when the helmsman needed to leave the tiller for a few minutes he had to call someone to take over, because relying on the autopilot would result in either broach or jibe. It keeps course for a minute and then at one point goes more than 30 deg off course (usually upwind) prior to the delayed corrective action by the autopilot. Then it becomes even worse, because the correction is too big and if the helmsman's does not interfere on time, a jibe is inevitable. I have heard that this autopilot is clever and needs some time to,adjust to wave pattern but I find this adjustment period (don't know how long) to be very dangerous.
Rumen

 

[pvb]

There's a fair bit of commissioning and seatrial work needed to set up the SPX10. Was this all carried out in line with Raymarine's instructions?

 

[FWB]

I have a Raymarine S1 autopilot on my tiller steered 9 ton gaff cutter.
The pilot will steer the boat accurately on all points of sail.
The important bit is that I managed to fit a rudder reference unit. The pilot does not perform so well without the rudder feedback information.

 

[BERT T]

Some of these might be worth checking as they can cause erratic performance.

• The SPX 10 does not require a rudder reference and is not supplied with one.
However if the SPX 10 is being used with an extreme performance boat, the addition
of a rudder reference may provide enhanced performance.

Grounding the SPX SmartPilot
CAUTION: SPX systems MUST be connected to ship’s ground. Failure to
connect the unit to ground may cause it, or other on-board electronics to
function incorrectly.
Use a dedicated earthing plate (e.g. dynaplate) in contact with the water.
• Use flat tinned copper braid, 30 A rating (1/4 inch) or greater. Equivalent stranded
wire diameter 4mm or greater.
• Keep the length of the earth braid as short as possible.

CAUTION: Connections to other equipment
If you are connecting Raymarine equipment to other equipment using a nonRaymarine
cable, you MUST attach an appropriate suppression ferrite to the cable
near to the Raymarine unit.

 

[G12]

Was it sailing a compass course or an apparent wind angle?

 

[Olianta]

There's a fair bit of commissioning and seatrial work needed to set up the SPX10. Was this all carried out in line with Raymarine's instructions?

I have received the boat directly from the boat yard but I don't think that sea trial work has been done. I should say that the boat is already two years old and so far I have not had any complaints before the ocean passage.

Rumen

 

[Olianta]

Some of these might be worth checking as they can cause erratic performance.

• The SPX 10 does not require a rudder reference and is not supplied with one.
However if the SPX 10 is being used with an extreme performance boat, the addition
of a rudder reference may provide enhanced performance.

Grounding the SPX SmartPilot
CAUTION: SPX systems MUST be connected to ship’s ground. Failure to
connect the unit to ground may cause it, or other on-board electronics to
function incorrectly.
Use a dedicated earthing plate (e.g. dynaplate) in contact with the water.
• Use flat tinned copper braid, 30 A rating (1/4 inch) or greater. Equivalent stranded
wire diameter 4mm or greater.
• Keep the length of the earth braid as short as possible.

CAUTION: Connections to other equipment
If you are connecting Raymarine equipment to other equipment using a nonRaymarine
cable, you MUST attach an appropriate suppression ferrite to the cable
near to the Raymarine unit.

I will check with Raymarine about the rudder reference unit, regarding founding and connections, I am sure everything has been done properly.

Rumen

 

[Olianta]

Was it sailing a compass course or an apparent wind angle?

We were sailing on a compass course.

 

[duncan99210]

I don't have the same type of autopilot computer as you do but one technique I've used is to set an initial course some thirty or forty degrees off the required course thus with the wind more on the quarter. This is an easier task for the autopilot to stabilise onto. Once the boat has settled down onto the set course, I then use the + - buttons to change the course gradually until the boat is settled onto the correct course. Seeing as you mentioned the autopilot being unable to stabilise on the selected course, perhaps this is worth trying?

 

[dom]

AFAIK (more than happy to be corrected here) the SPX10 has a fairly basic gyro, but not to the level of being able to accurately interpret the changing rate of turn. Raymarine's newer "ev" kit is able to do this, which means that the pilot doesn't need the gain constantly twiddled with, as the AP instantly knows that the boat is say swinging too slowly/in the wrong direction, in relation to the amount of rudder it is applying and can whack the rudder on to correct. If the next wave is smaller the AP will also "spot" that and won't wham the tiller all over the place.

I would certainly follow the technical advice ^^^^ as the SPX10 is a far batter piece of kit than say my 2002 vintage Flintstone's gear, but having experienced almost identical problems to you I am in the process of upgrading my AP and so far I'm coming down on the side of the Raymarine ev.

Edit: I should have added that those I have spoken to really rate the SPX10, so thinking about it, this AP should probably do a better job downhill than it seems to be doing.

 

[nickd]

I have an SPX5 on a Konsort and it steers fine on any point of sail.
I installed it, the set up once installed is a bit of a faff but then no problems. I would suggest putting back to factory default and then going through the set up process again. There are a lot of ways of tweaking its responsiveness may be one or more of these are set at an extreme?

 

[Olianta]

That's to all of you who bothered to respond and advice. I will follow some of the suggestions. I have contacted
also Raymarine and they watt to check the boat. Hope problem will be sorted out because we will sail back from the Carribean to the Med in May and most probably will be only two as a crew. But I think the return trip (direct route) will not need spinnaker sailing.

Rumen