I found my GPS

I finally solved the problem with my Raystar 125 GPS.  The trouble was embarrassingly trivial; I had swapped two leads on one plug in the lazarette of the boat, where testing it was very awkward.

After I straightened it out, the whole suite of electronic navigation devices started to operate.  

I see a green flashing light on the LED for the GPS; I see a green LED on the front of the AIS.  I see periodic data flashes on the NMEA multiplexer, indicating that it sees data on one of its channels.  I see a flash on the AIS light on the VHF antenna splitter, about every 5 minutes or so, indicating that it is transmitting my position and vector.  I can see the ship's location on the screen of the VHF, which implies that it is prepared for emergency message transmissions.

The radar scanner is still at the repair depot, but I can receive and transmit AIS data.  Among other ships, I can see that of the Charles W Morgan, which is moored 6 miles away at her pier in Mystic, testing her navigation equipment in preparation for the start of her 38th voyage tomorrow. I can see my own location and vector on the Web site "Marine Traffic", which intercepts and displays the locations reported by AIS.

I have not moved from the pier, but my location is displayed correctly on the chartplotter.

When the rain ends later this weekend, I will load the hotel supplies on to the boat and commission the water system.

My GPS seems to be lost

Last fall, I removed the Raystar GPS 125 installed in the mizzen mast, in favor of the antenna for my AIS 650.  This spring, I found that I cannot use the AIS 650 for navigation, so I am attempting to install the GPS 125 again, but it refuses to work.
As I read the manual, I should supply + 12VDC to the cable connected to the GPS, ground its green and brown wires to its shield, and watch the GPS boot (red flashing LED), listen (amber flashes) and acquire a fix (green flashes every 2 seconds).  If I wish, I should be able to read the serial data output on its yellow wire, measured with respect to the ground.
What happens is more subtle. When I apply power, sometimes the LED flashes red, sometimes it does not.  Often the LED stays stubbornly off.  I have removed all other connections to the unit, but I can't seem to get it to operate consistently.
Apparently I cannot buy a direct replacement for the Raystar 125 from Raymarine.  They now sell the Raystar 130, which has no NMEA 0183 output, favoring instead their proprietary Seatalk (ng) bus.  Using this GPS would require at least one adapter, from Seatalk (ng) to Seatalk (1), and then some arrangemet to convert its data from Seatalk (1) to NMEA 0183.
I understand that Garmin still sells a GPS that uses the NMEA interface.  I hate to add another brand to my boat, but it seems that this may be the path of least complication in the short run.
On the other hand, the Seatalk (ng) bus is a lovely adaptation of the NMEA 2000 "standard", implementing a nice moisture-resistant version of a CANnet.  Its topology is backbone-and-drop; it has fairly wide bandwidth, and its operation is largely independent of any particular unit.  Unfortunately, very little of my electronics could be reused.

Diverse, but limited, successes

As I wrote before, all of the electronics attached to the mizzen mast I had rebuilt malfunctioned when I launched Rune this spring.  After finishing a depressing set of commissioning tests, I set out to repair the electronics, one unit at a time.
I decided that repairing the Raymarine Automatic Identification System (AIS650) should be easy.  Its external unit is a simple antenna, but it still wasn't producing any fixes.  I walked through the six connectors between the receiver and the antenna, and found both an intermittent short and an weak open.  After finishing, I was rewarded by a simple green LED on the front of the machine.
I dismounted the radar scanner between rain showers, and sent it to its birthplace for refurbishment.
Although I find it amazing to learn, the GPS in the AIS650 cannot send its data to the chart plotter. In order to use the C70, I have to replace the Raymarine Raystar 125 GPS that I removed from the mizzen.  Eventually, I shall build a new platform on the  mast; it is really the most sensible place for the GPS sensor.  In the interim, this year, I shall install it on the top of the mushroom vent on the transom.  To firmly affix the GPS without damaging the vent, I shall replace its beautiful bronze lid with a tawdry one of plastic, to which I will bolt the GPS.  Holding the plastic lid onto the vent will be its own problem.
The Raystar 125 is a full GPS system, with its own integrated antenna, receiver, and digital output.  Therefore I shall just connect it to the Seatalk(tm) network when it has been installed.
On Thursday, when I arrived at the boat, I heard the engine alarm bell sounding from the dock!  Since the engine was not running, it was very strange.  To stop the bell, I had to open the main battery disconnect.  I then turned off the engine alarm override, and found that the engine started as it had before.  I concluded that I had partly moved the alarm override switch into its shut (non-override) position when I was in the locker next to it, and that wave action moved it all the way during the night.
The engine started, but not the way it should have.  I had already noted, last year, that the alarm was not operating as expected, and the problem was on the list for later resolution.
When the key is turned to energize the engine, the oil pressure alarm is designed to sound, and then be defeated when the glow plugs are energized.  When the engine starts, and the oil pressure meets its minimum, the oil pressure limit switch closes, and the alarm is kept off.
I found that the positive wire for the alarm circuit was connected on the supply side of the engine switch, rather  than the engine side.  Hence the DC was supplied to the alarm even when the engine was off.  Reconnecting the wire in accordance with the wiring diagram corrected the engine operation.

Spring commissioning 2014

The masts are now stepped, and boat has moved to her summer berth on Margin Street.  Engine commissioning went without a hitch, replacing the sea water impeller and the first two fuel filters.  The trip  out of the boatyard was mercifully routine.
The post-launch checks are not going well.  When I powered the Raymarine C70 multifunction display, I saw a message "No Scanner". I have checked the continuity of the conductors in  the mast cable, and they are good.  The scanner itself, a Raymarine type RD218 2KW radome, seems to have failed.  I am troubleshooting with the aid of the Raymarine support forum, but I am sure that I am going to have to dismount it, and return it for intensive care.
In order to use the Raymarine AIS650 in active (class B) mode, I must use its internal GPS with the antenna mounted on the mizzen mast.  I have been unable to fix a position.  The status LED on the front panel of the AIS is red, indicating a fault the electronics can see.  The cable resistance measures a short, indicating that one of the connectors is bad. Troubleshooting is beginning.