Crap Robertson/Simrad autopilot

[tcm]

I'm sure that on other boats the autopilot is better than on this one. I used to be able to set a waypoint miles away on a previous boat and it would hold that course to within a degree or two.

But this robertson simrad things is rubbish - wildly moving ten degrees either side even in only a slight sea. I set it to near the correct course, then pres the nav thing and it says "turn 38 degrees" and then off it goes, so praps the fluxgate thing is set wrong.

But even with just pressing "auto", it's crap.

Burgundyben fidddled with it and jfm told me it was sposedly good gear, so none of this is my fault, of course.

Does it need some setting up? Who might do that on the south coast? Or praps chuck the whole lot away and buy some other gimcrackery? Or bigger rudders?



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[Mike21]

Other than going thru cal procedure, would be worth checking response is not set too high as this can cause it to wonder all over the place.

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[Moose]

no1 Moose says its your funny leccy steering stuff......

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[jfm]

It is normally good gear. I have used it on 2 boats (old fairline and my brother's trwler thing) and it's fine. Problem is that the eyeties never set it up right. When it was new the fluxgate heading was 30deg different from the GPS COG and the compass, or sommink. So it can't have been set up right, or is bust.

You need to get a good boat lectronic person on for half a day.

If you do decide to chuck it out, this new Raymarine gear with gyro as well as fluxgate is totally fab

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[sailorman]

i had the "wheel pilot" by navico it was also poorly designed & built, its clutch gave-up @ 9 months.
i have had a raytheon 6000 now for 5 seasons & its fantastic

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[burgundyben]

Guilty as charged.

Er, yes, I did fiddle wiv it, it got better, then it got worse again after turning off and I lost interest, when it was better it was still a bit rubbish.

I drove a Flemming 55 from Hamble to Oslo and back with one and it was exellent.

So I think yours is either poorly or set up badly (which is what I fiddled with).

<hr width=100% size=1>I didn't knacker TCM's copper it was Trazie

 

[stellican]

your local specialist repair co are M.E.I at Port Solent provied you can find your way back there
tel 02392 326366

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[Oldhand]

I have experienced similar disappointing performance with a Simrad installation on a sailing vessel. Poor course keeping and lots of unecessary rudder movements. I recently replaced the standard fluxgate compass with the new RC25 rate enhanced heading sensor. This has transformed the system into an excellent autopilot. I strongly suggest that for the sake of £460 odd, you need to do the same.

One may think we shouldn't have to do such modifications but autopilots have to be designed to operate in a very wide range of craft and thus compromises are made. However, there are always some craft where the handling characteristics don't suite the autopilot, especailly if a "resonance" type situation is created between the craft's steering and the autopilot responses. This can occur with any make of autopilot and I am advised, by a major S. Coast electronics supplier/installer, is virtually always cured by fitting a rate enhanced heading sensor. It has certainly worked with my Simrad system.



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[JerryHawkins]

Very interesting post! Which Simrad autopilot do you have? I have the simple WP30 which has a fluxgate compass built in. Although I'm generally happy with its performance it does do an aweful lot of small rudder adjustments. Do you know if the RC25 can be connected to this system? If so, would it automatically over-ride the built in fluxgate?

Cheers, Jerry

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[Observer]

I think that's what's happening on our AP22. Seems OK in auto mode (just setting a course manually) but as you described, get a wild turn when set to NAV mode even if only small correction needed. Wonder if it's the rate at which the 'current heading' info is refreshed?

<hr width=100% size=1><A target="_blank" HREF=http://aflcharters.co.uk>Dream Dancer</A>

 

[Oldhand]

I think you are out of luck Jerry. The series of separate Simrad heading sensors are made to work with what was originally the "Robertson" range of autopilots. Simrad bought both Robertson and Navico and thus have 2 different ranges of autopilot. The RC25 is standard supply with the top of the range AP 20 series model and can replace the RFC35 fluxgate supplied as standard with lesser AP20 and AP11 series models. The Simrad US web-site is the best source of information.

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[JerryHawkins]

Thanks for that. Yes, I did have a look through "simradusa" but the only reference to an external compass for the WP or TP series pilots is the Navico ATC600 which connects to the green & white "chorus" wires. I don't think this is available any more and in any case it seems to be a simple stand-alone fluxgate rather than rate compensated and was only used where you had a steel hull and the internal unit wouldn't operate.

Cheers, Jerry

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[Andrew38]

I have the same Simrad autopilot on my Broom 38 and have experienced similar issues. Mine is linked to a CR42 chart plotter which I have learnt seems to raise some of the issues. When setting up on to "Nav" from a preplanned route it's basically fine unless you get off course due to either dodging another boat or because you've used waypoint advance. It then wants to take you back onto the preplanned track not directly to the next waypoint. I presume this is a safety feature designed into the software but it does want to do some vast course changes very quickly! Regarding the "hunting" for a course I gain have the same problem and find that the system is very sensitive to sea conditions. The unit is probably set up to "Auto" in the "seastate" sub menu but if you adjust it (hit "nav" twice quickly and you will enter the set up menu, use red/green arrows to scroll down to "seastate" and then use round knob to select auto or manual 1-10). It helps but it can still be twitchy.

I recommend speaking to Jim Stagg or Andy at MEI or directly to Simrad.

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[jimg]

It took me a while to get used the Simrad after using Raymarine for years. In Simrad Nav mode you can press Dodge, then steer a round the obstruction, then you MUST press Nav again to continue on a revised track from that point. If you read the manual ( who does? ) you see it has several modes of operating. If you dodge by pressing Nav repeatedly to get in and out of Nav mode I think it returns to the "old" track which can involve a big course change. Manual is down on the boat.
Good ;- Press Nav (on) then press Dodge and steer, Press Nav (on)
Bad:- Press Nav (on), Press Nav (off) and steer, Press Nav (on).
Hope that makes sense!
Cheers
Jim

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[jfm]

.... I thought you pressed Dodge a second time, to turn off dodge and return to nav mode, but haven't used on for a while. Maybe you can do it both ways?

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