Aboard Astraea

No GPS position

It all started when I turned on the Furuno RDP-149 NavNet VX2 chartplotter and Icom 504 VHF radio for the first time. I noticed the radio said “No Position No Time” and it was right next to the chartplotter that gets its position and time from its GPS antenna. I want our location to be inputted in to VHF radio so if I need to press the distress button an automatic call can go out to the Coast Guard and our position will be automatically transmitted. It’s also nice that our position will be displayed on the radio so it’s easy to tell buddy boats where we are, or for a less emergent situation like a Securite or Pan Pan call.

So, a little about making the right connections. There’s a protocol called NMEA that allows maritime electronics to communicate. All you have to do is figure out how to set up and connect the equipment and it should work. I read the manuals and did a quick internet search and found that it’s easy to connect my radio and chartplotter together using two wires so the chartplotter can feed the radio time and position data.

I downloaded the chartplotter manual and VHF manual from the manufacturer’s websites.

Icom M504 radio NMEA wiring from the online manual

Wiring data for the Furuno Chartplotter NMEA connection on Data 4

NMEA works like a momma bird and a baby bird (feeding data instead of regurgitated worms). For my setup the momma bird is the chartplotter feeding (transmitting) data to the VHF radio which eats (receives) the data. I used the chartplotter’s TD_DT connection on pin1 of the Data4 jack to transmit the data to the inner conductor of the NMEA IN lead on the VHF. The only tricky part was fining out what “NMEA IN (-)” on the VHF should be connected to on the chartplotter. I guessed that it should connect to the SHIELD/GND and it worked. As soon as I touched the wires the GPS position and time were instantly transmitted to the radio!

Testing the setup from the chartplotter

Testing the setup with twisted leads

Now there’s location showing up on the radio display!

I soldered the connections and put heat shrink on my custom wiring to make it professional. The leads are secure in the back of the chartplotter so I won’t buy the $65 Furuno cable. If this installation was outside or in a splash zone I’d buy the waterproof Furuno cable, but it’s far enough under the companionway I’m not concerned about water intrusion.

The connection on the back of the radio all covered up and ready for daily use

After reading more in the Icom manual now I want to connect an AIS to provide ship position information on the chartplotter. All in all the project took me an evening on the boat after Sully went to sleep.

We’ve been out sailing on Astraea at least once a weekend for the past few weeks. We’re really comfortable taking the boat in and out by ourselves but it makes it nice to go out with other people, or have a destination for our sailing trips instead of just going out and cruising the bay. Friday we went out for a quick sail with Atmun and Justin, some guys I know from work.

Atmun ghost riding the jib

Saturday we took Astraea across the bay to Trent and Brittany’s house. Since the first time we went to their house I said we should take our boat over and dinghy ashore. We finally did it a year later.

Anchored off the Silver Strand in San Diego Bay

Trent, Bella and Sullivan riding the dinghy

Playing with Bella’s toys

Still securely anchored off the strand before sunset

We didn’t spend the night because anchoring isn’t authorized overnight. As we took the dinghy back to Astraea the San Diego Police boat was pulling up towards us to check if we were doing OK. We said, “No problem, just took a little longer to get underway than expected.” They left us alone to go back to Pier 32.

The next day we hung out with Eric from Coconutz.

Eric and Sully at Ballast Point Brewery

Then we had some tasty Mexican food at Miguels in Point Loma and came back to the boat to play. We took Astraea out and flew our new drifter for the first time. The drifter is a giant sail made of lightweight material and it’s used for sailing downwind off the roller furler like a jib.

The maiden sail of our new to us drifter from Minney’s Yacht Surplus.

Self drifter shot

It’ll take more experimenting with the drifter to find the best way to sail and trim it. We were cruising along at 5 knots with just the drifter up. If we’d also have had the mainsail up I’m sure we’d be making 7.2 knots, hull speed. Thanks to Eric for helping manhandle this gigantic sail.

Eric rolling up the drifter

I’ll be getting back to work on boat projects later, it’s been great to just hang out with friends and not worry about working on the boat for a while. As the weather stays nice I’ll get back to projects.