Simrad AP25 Autopilot compatibility issue help!

[Shibumi]

Hi Folks,
Hopefully somebody can answer this one.

I have a Robertson / Simrad autopilot computer, hydraulic pump & ram, and rudder feedback already installed by a previous owner - superficially at least it all looks virtually as new.

Unfortunately the previous owner removed and discarded the Simrad autopilot head unit so I never even got to see it.

I have been offered a new (but obsolete) AP25 head unit Simrad part number 22087811.

The computer is Simrad J300X-40 - part number 22081954

Both are NMEA 0183 and both part numbers start with the same 2208 number - anybody know if they are compatible?

Cheers folks.

Steve

[Tim B]

If both units talk in NMEA, then they should be compatible. You can monitor the NMEA data stream by plugging a PC in and "hijacking" the serial stream. Most PC serial ports will handle the NMEA standard (which is not quite PC Serial), though you can get converters. Just make sure you get Rx and Tx the right way round, otherwise it won't work.

Cheers,

Tim B.

[michael pierzga]

No....Simrad talks a "New " version on NMEA. NMEA2000. From what I understand the NMEA sentance is the same but the velocity...Baud rate... is much faster. The NMEA2000 sentence requires a 100 dollar SIMNET converter to bring it down to NMEA speed . Im going thru this dilemma at the moment by trying to use the GPS NMEA output of a Simrad AIS to power a DSC radio with GLL and the basic sentence. Next week delivery, then my DSC will work again !. Sorry I cant remember the part number...ask your Simrad man... I also understand that there is a converter for SgCosg , Simnet NMEA2000 conversion. Many older Auto pilots used Si, Cosi format

[Submarine Tom]

Shibumi,

Talk to the manufacturer. Don't hang up the phone until you're satisfied with the answer, even if that means asking to speak to a supervisor, or higher. It's their product, they have a vested interest in helping you be satisfied with it.

-Tom

[Shibumi]

Thanks for all the help guys.

I've emailed Simrad tech support to see if the AT10 converter will do the trick (I think that that is the one that Michael is referring to)

Fingers crossed.

Steve

[michael pierzga]

Yes indeed.... I believe its called an AT10 simnet converter ...Im waiting for mine. 64 euros I believe.

Its possible that your unit is different, I cant remember what MNEA sentences an autopilot requires ?.... heading, waypoint, wind...... but certainly the Simrad agent should be able to advise on the required NMEA data sentence format .

[Shibumi]

Michael,

I've just heard back from Simrad - apparently if I change the Eprom chip on the J33 to a 220 884 62 both units will talk to each other - just ordered the chip at about $75 equivalent in Uk.

We shall see!

[michael pierzga]

Ah yes...Eprom chips.... Unfortunately not to my taste... For Chips...I prefer the sour cream and onion ones..

Sure hope you have all the " special" plugs and cables to wire that octopus up....seems like Im always needing some cable...only a 10 cm long jumper.... BUT I have to buy a 3 meter job, coil it all up, cable tie it, then stack it ontop of all the other coiled up 3 meter cable piles....Arrrrrrrr...electonic gizmos

[Submarine Tom]

Relying 100% on electronics to navigate is not a good idea. It is a slippery slope to become dependant on them and then, when they fail, you're screwed.

Your eyes and a chart should be your primary navigation tools, electronics are a luxury, secondary and subject to fail, for a number of reasons, without notice.

They can be very problematic and expensive.

Beware.

-Tom

[Tim B]

Just a few points:

"Both are NMEA 0183 and both part numbers start with the same 2208 number - anybody know if they are compatible?" - If this is true, then they will be, from later posts clearly they do not both use NMEA 0183.

"From what I understand the NMEA sentance is the same but the velocity...Baud rate... is much faster." - No it's completely different, it's actually CAN-BUS technology. If it were just the baud rate that was higher, that would be an easy fix. See http://en.wikipedia.org/wiki/NMEA_2000 this will all get replaced, of course, when we all get round to using ethernet and doing things properly (and no, there are no significant problems with using eth in "industrial" or maritime environments).

Sub Tom:
I agree - eyes can be problematic and expensive... oh, you meant the electronics. As much as I am an advocate of performance-enhancing electronics, I second your warning. There is no excuse for not having a paper chart, pencil, binoculars (with compass), bearing compass, local clock and GMT clock on board. Some form of sextant is also useful.

Cheers,

Tim B.

[Shibumi]

Originally Posted by Submarine Tom

Relying 100% on electronics to navigate is not a good idea. It is a slippery slope to become dependant on them and then, when they fail, you're screwed.

Your eyes and a chart should be your primary navigation tools, electronics are a luxury, secondary and subject to fail, for a number of reasons, without notice.

They can be very problematic and expensive.

Beware.

-Tom

Tom, the equipment in question is an autopilot to hold a straight(ish) course - it has no navigational function.
I've been skippering both private and commercial vessels around the world since the 1960's and I'm very happy with a paper chart and sextant.

Thanks,

Steve

[michael pierzga]

And Steve...when you finally get your hands on the CHIPS and wire that baby up, use this precaution for commissioning .

Go up to the wheelhouse , with one hand grab the binoculars and zero in on the smoke stacks of the local powerplant , then with the free hand.... THROW THE SIMRAD MAIN BREAKER ...

If you observe smoke frantically billowing out of the powerplants chimneys and street lights flickering in the distance.... you've go a problem.. SYSTEM OVERLOAD.... probably bad chips or some kinda swine flu in your CanBus. .