What is a MMSI?

In boating, the term MMSI is used a lot, but what does it really mean? I'll break it down and give some references where you can get more details.

The MMSI is one of three identifying numbers on your boat. Another one is the HIN. See this article about the HIN for your boat. The third number is the Vessel Identification Number, which is the identifying number for the boat.

MMSI is an acronym for Maritime Mobile Service Identity. It is meant to be a unique identifier to identify a ship or coast guard station, and other maritime entities. It consists of a nine digit number, and specific digits in the MMSI have special meaning. The first digit indicates (with a few exceptions):

  • 0 Ship group, coast station, or group of coast stations
  • 1 Search and Rescue aircraft
  • 2-7 Individual ships, further broken by region
    • 2 Europe
    • 3 North America, Central America, and the Caribbean
    • 4 Asia (except the Southeast)
    • 5 Oceana and Southeast Asia
    • 6 Africa
    • 7 South America
  • 8 Handheld VHF transceivers
  • 9 Devices(such as EPIRBs and AtoNs)

There are three digits, usually the first three, called the MID (Maritime Identification Digits). These together identify the flag state (country) that issued the MMSI. The definitive list of these can found at the International Telecommunication Union web site. Some countries have multiple MIDs assigned to them. Some landlocked countries don't have any MIDs assigned to them. The MIDs 338 and 366-369 are assigned to the United States, but 303 is used in Alaska, 358 in Puerto Rico, 379 in the U.S. Virgin Islands, 536 Northern Mariana Islands, and 559 American Samoa. Canada is assigned 316. If the MID is the first three digits, then that leaves six digits to assign to boats. The FCC (Federal Communications Commission) only issues numbers that ends in zero (leaving five digits), but allows other entities to issue MMSIs for pleasure craft. However, the MMSIs not issued by the FCC should not be used in international waters, as the numbers are not migrated to the international databases. You can get an MMSI from these organizations in the United States:

Suppose you get a non-FCC MMSI and are cruising in Canada. You hit an iceberg in some isolated fjord, start sinking like the Titanic, and press the DSC "panic button" on your VHF radio. The Canadian Coast Guard systems will look in their database of MMSI numbers and not find your boat. This can delay rescue efforts as they try to track down info on what boat is sinking. If they do manage to rescue you, on top of your other problems you may be having a little discussion about using unauthorized communication systems in Canadian waters. If you are going outside the United States, get your MMSI from the FCC. If you do have a non-FCC MMSI, you will need to cancel it with the entity that issued it and acquire a new one from the FCC.

The MMSIs that start with digits outside 2 to 7 don't follow the same format, so if you have a handheld VHF with DSC or an EPIRB, the layout of digits is different. For example, an EPIRB has the format 98MIDxxxx.

Obviously, there are limitations on the number of MMSIs that can be issued. Canada, with a single MID, can only issue MMSIs for 10000 EPIRBs. One way that this is handled is that MMSIs are sometimes reissued. A MMSI in the U.S. issued by the FCC is valid for 10 years, after which it must be renewed or it expires. An expired MMSI can presumably be reissued. To cut down on the changing of MMSIs, the FCC does not let end-users change the MMSI on a device. After it has been entered, it must be delivered to an authorized agent of the manufacturer to change the MMSI.

The United States currently has registered about 12 million boats. The five MIDs assigned to the continental United States can allocate only 5 million MMSIs, and only 10% of them can be issued by the FCC to work internationally. However, most boats do not have a MMSI assigned, which is why the pool has not been exhausted. However, at some point, the United States will need to acquire some more MIDs. Fortunately, the ones between 380 and 399 are currently unallocated.

A MMSI in the United States is issued to a single boat licensed by a single person, company, or other organization. If the boat is sold, the FCC has a technique where the MMSI can be transferred, but it requires the cooperation of both the seller and the buyer. If you buy a boat, you might want to put into your conditions the transferring of the MMSI.


Installing Raspberry Pi and SignalK on a Boat

This is a summary of all of the information necessary to install a Raspberry Pi on a boat. Although there are a lot of steps, the process is relatively straightforward, especially with the script provided.

Some pieces have been covered before on this site, but this will put it all in one place. The links to Amazon are affiliate links that will contribute a small amount to support this site.


This article makes the assumption that you already have:
  • A NMEA 2000 network. This should have at least a GPS on it.
  • A MMSI. This number identifies your boat. You can get one for free from BoatUS, but if you are going to travel internationally, you need to get one from the FCC.
  • A WiFi router with a connection to the Internet. You will need to know the router name and the password. We use a Galaxy Tab A7 Lite configured as a mobile hotspot. This adds about $20 a month to our cell phone bill, and allows constant connection of the Internet from anywhere there is a T-Mobile cell tower. T-Mobile frequently gives them away with a two year commitment. Some marina WiFi routers will not work for this as they block direct connections between devices on the router. The router should allow the laptop to connect to Raspberry Pi and both the laptop and the Raspberry Pi to reliably connect to the Internet.
  • A laptop computer with WiFi, Remote Desktop Client, and SSH. This will provide your connection into the Pi through SSH or Remote Desktop to configure it. We use an older Microsoft Surface Pro which takes up less space on the boat than most laptops. You can find them used on eBay. The laptop needs to have SSH installed on it. SSH is an optional component in the Windows operating system, so you may need to install it. Windows computers should come with Remote Desktop Client.
Gather and record this information

The Hardware

You will need the following hardware. You may have some of it on hand.

  • A Raspberry Pi. There are several models, but putting a more powerful one on the boat makes sense as you can add more monitoring.
  • A Pican-M hat board. This provides the input from the NMEA network, including the 12V power from the network.
  • A case for Pi and Pican-M. This encloses both and provides cutouts for all the necessary inputs.
  • A NMEA 2000 tee connector. This adds a drop location to the NMEA 2000 network.
  • A NMEA 2000 drop cable. These cables come in various lengths. Purchase one that is the shortest length necessary to go from your NMEA tee connector to where you are mounting the Raspberry Pi.
  • A micro SD card. Should be at least 32 GB, but more is better. We managed to accidentally completely fill a 32 GB card with log files, which made the Pi very unhappy. Note that not all SD cards are equal. For a system like this, you should get an A2 rated card.
  • A micro SD card reader. If your laptop doesn't have one built in, you can get an external one. Most micro SD cards come with an adapter that allows them to be used in full-sized SD card slots.

Make sure the NMEA 2000 network is powered off. Plug the Pican-M hat board onto the Raspberry Pi. Add the NMEA 2000 tee to the backbone. Attach the drop cable to the tee and the Raspberry Pi.

Optional Hardware

For the initial configuration of the Raspberry Pi, you may want to connect it to a keyboard, mouse, and HDMI monitor. Any USB keyboard and mouse will work. You will need a micro-HDMI to HDMI cable to connect the Raspberry Pi to the monitor. This optional hardware will allow monitoring and debugging if something goes wrong with the WiFi connection. To build a NMEA 2000 network off the boat for testing purposes, you can use this kit. To supply power, you can use a 12V power supply.You can also use a USB-C cable to power it from some other computer.

Configuring the SD Card

You will need to configure the SD card. For that, the easiest thing is to run the Raspberry Pi imager on your laptop. Follow the steps below. You can also see this video that walks through the process.

  1. Plug the micro SD card into the laptop. Make sure that there is nothing valuable on it, because this process will delete the entire content of the SD card.
  2. Download and install the imager from the Raspberry Pi web site.
  3. Run the imager.
  4. Click the "Choose OS" button and select the Raspberry Pi OS (32-bit) operating system.
  5. Click the "Choose Storage" button and select your micro SD card.
  6. Click the Gear advanced button in the lower right. Set the following options, checking the checkbox next to each one:
    1. Set Host Name. This is what you will use to connect to the Raspberry Pi. We recommend the name of your boat. The name can only contain the letters A-Z, the digits 0-9, and the hyphen (-). It cannot contain spaces, so if your boat is named The Blue Whale, use either TheBlueWhale or The-Blue-Whale. The name is actually case insensitive, so capitalization doesn't matter. The host name will have .local appended to the end. Write this down so you don't forget.
    2. Enable SSH. Use Password Authentication.
    3. Set Username and Password. Use "pi" for the username, and type a password that you can remember and easily type. You will be typing this frequently. Write this down so you don't forget.
    4. Configure Wireless LAN. Type the name of your WiFi router and its password. Set the wireless LAN country to the two letter country code of the location of the router.
      Note that the name of the WiFi router entered is case sensitive and must exactly match the given router, including capitalization. If the WiFi does not connect later, check that you got this right.
    5. Set Locale Settings. Set the Time Zone to a city in your time zone. Set the Keyboard Layout to the layout that is on your laptop.
    6. Check Play a sound when finished.
    7. Check Eject media when finished.
    8. Leave Enable telemetry unchecked.
    9. Click Save.
  7. Click the "Write" button. The program will confirm that you wish to overwrite the existing content of the card.
  8. When it shows it is complete, remove the micro SD card from the laptop.

Logging into the Raspberry Pi and Configuring It

  1. Make sure the power is off on the NMEA 2000 network.
  2. Insert the micro SD card into the Raspberry Pi.
  3. Turn the power on the NMEA 2000 network. You should see the red power LED on the Raspberry Pi inside the case through the vent holes. There will also be a green LED that shows disk activity. The first time you power it on, it will take several minutes before the operating system is fully booted as it has some configuration steps it needs to perform. This varies based on the size of the SD card. A 32 GB card took only a couple of minutes, whereas a 512 GB card took about 15 minutes. If you connect an external monitor, you can watch the progress, although much of the time the screen will be blank. The Raspberry Pi should log into the WiFi router automatically, so check the connection on the router if you can.
  4. On your laptop, connect to the same WiFi router that the Raspberry Pi is connecting to.
  5. From your laptop, create a command prompt. In Windows, you can do this by typing "cmd" in the search box on the task bar and pressing Enter.
  6. Enter the following command to log into the Raspberry Pi using SSH. You will need the Host Name and Password you assigned above. If the Host Name is The-Blue-Whale.local, type this and press Enter:

    ssh pi@The-Blue-Whale.local

    The first time you do this, it will warn that it has never seen the key before and do you want to continue. Type "yes" and Enter. It should prompt you for a password. Type the password and press Enter. If all goes well, it should log you into the Raspberry Pi. Note that entering the password does not echo or show up as asterisks.

    What if it doesn't log in?

    If it complains that SSH is not recognized as a command, you will need to install SSH as discussed above.

    If it responds that it could not resolve the host name, then you will need to connect using the IP address the WiFi router assigned to the Raspberry Pi. This can be a bit of a guessing game if you do not have access to the router or do not have the monitor and keyboard attached to the Raspberry Pi. Find the IPv4 local IP address of your laptop, then try changing the last number of the IPv4 address to others that are nearby. For example, if the laptop IPv4 address is, you should try and other nearby numbers. Try to login with ssh pi@

    If it responds that the connection timed out, then something has gone wrong with the network connection between the laptop and the Raspberry Pi and you will need to debug where the connection is breaking down. Debugging that is beyond what we can cover here.
  7. Download a script that we created that configures the Raspberry Pi and installs SignalK. Type this command that downloads the current script from the Internet:

      curl -O http://www.xoc.net/downloads/installpi.sh

    This command downloads the file and places it into the current directory.
  8. Run the script as "root". Type

    sudo bash piinstall.sh

    This script performs the following tasks. After each one, it will pause and have you press Enter before continuing with the next one.
    1. Change the pi to boot to a command prompt instead of to the desktop.
    2. Updates all the packages on the Raspberry Pi to the latest versions
    3. Installs nodejs and npm. These are a JavaScript library and a package manager for node packages.
    4. Installs xrdp packages that allows remote desktop into the Raspberry Pi.
    5. Fixes a problem with the xrdp packages.
    6. Installs and configures CanBus packages. CanBus is the protocol that NMEA 2000 is built on.
    7. Installs SignalK. The SignalK packages provides a services that turns NMEA 2000 information into easier to understand XML. It also installs a local web server that allows management of SignalK applications. The SignalK installer will ask you several questions:
      1. Where you want the SignalK configuration installed. You can just press Enter to place them in /home/pi/.signalk.
      2. The name of your boat.
      3. Your MMSI.
      4. Whether you want to use port 80 or port 3000 for the SignalK web site. You just just press Enter to use port 3000.
      5. If you want to enable SSL (Secure Socket Layer). You can just press Enter to leave SSL disabled.
    8. Reboots the Raspberry Pi.

Logging in to SignalK

  1. From the laptop, search for and run the Remote Desktop Connection app.
  2. Enter the Host Name or IP address of the Raspberry Pi in the Computer textbox. Click the Connect button.
  3. You may get a warning about the certificate. You can check the box for "Don't ask me again" and click the Yes button.
  4. The Remote Desktop program will show the Raspberry Pi login screen. The session should be Xorg, the username Pi, and the password the password you assigned to the Raspberry Pi. Click OK.
  5. The Raspberry Pi will show its Desktop. On the top bar click, the "World" icon that brings up the Chrome web browser.
  6. In the URL line on the browser, enter "" and press Enter. is the IP address of the local computer, and 3000 is the port number that SignalK listens on for a web connection. This will bring up the SignalK configuration web page."
  7. In the upper right is the menu icon. From here you can create a login to SignalK and log in. From here you can install SignalK applications that work with your boat.


Wiring the Instruments on a Catalina 320

We are getting close to finishing the update to our wiring on our 1994 Catalina 320 Achernar. As the boat came, it had the original Raymarine depth, wind, speed, and autopilot devices at the binnacle. It also came with an approximately ten-year-old AIS, antenna splitter, AM/FM radio, and chart plotter, as well as an ancient VHF radio, and Garmin radar dome on the mast. The chart plotter supports NMEA 2000, but the AIS only supports NMEA 0183 (see the other posts we have done about these technologies). The NMEA 2000 network on the boat only had three drops: 12V in, a Garmin 17X GPS antenna, and the Garmin 4212 chart plotter. The chart plotter showed radar and GPS, but none of the info from the devices at the binnacle, nor the AIS info. The AIS broadcasted the info about the location of our boat, but didn't have any way to show the location of any other boats.

Our goals:

  • A VHF radio that supports DSC
  • A VHF remote handset accessible from the cockpit
  • A chart plotter showing depth, wind, speed, autopilot, and AIS info
  • Saillogger recording the info on our travels with a reliable Internet connection
  • Replace as few of the instruments and devices as possible

Eventually, we'd like to replace all the instruments and devices with state-of-the-art equipment. But this will take a considerable amount of time and we'd rather be out cruising.

Since the VHF radio didn't support DSC, that required a replacement. We consider DSC to be a critical safety system on the boat as it provides a panic button that alerts the Coast Guard to our exact location should we run into problems. We replaced the VHF with a new Standard Horizon GX6000 (in retrospect, we could have gone with a cheaper radio and still met our goals). We also acquired the RAM4 wired remote microphone. We considered the wireless remote microphone, but the reviews we read said that the wireless version was unreliable. Unfortunately, the squelch on the radio failed shortly after we installed it, causing the radio to blast static at full volume. We had to send it in for warranty repair, which required almost six weeks to turn around, plus the cost of shipping it to them.

We ran new wires between the "garage" (the large locker on the port side of the Catalina 320) and the panel to the right of the chart table in the cabin. The two wires we ran were a NMEA 2000 backbone cable and the cable to support the RAM4 microphone. There is a channel for wires that runs across the top behind the galley cabinets. We opened the panel on the right side of the top right cabinet that allowed a fish tape to be extended from the electrical panel, through the channel, to the garage. This made fishing the new cables relatively easy. There is lots of room for cables in the channel.

Wires run under the pedestal in the aft cabin

In the garage, we added two blocks that provide the connection of the NMEA 2000 backbone to the devices at the binnacle. The ST60+ depth, ST 30 wind, ST 30 speed, and ST4000+ autopilot were all connected to each other with a SeaTalk1 network. However, the network did not extend anywhere else. We ran a new SeaTalk1 cable from the garage to the port aft lazarette, then under the pedestal in the aft cabin and up the stanchion to the devices. This required taking off the cover from under the pedestal in the aft cabin, which was held in place with bunch of screws. We removed two cables that ran up to the instrument panel: an obsolete and unused depth cable and a power cable. This freed space inside the port-side stainless steel pedestal support stanchion. We pulled the SeaTalk1 cable by taping it to one of the cables we were removing. We had to cut the SeaTalk1 cable to pull it, then splice the cable back together because the cable end was too large to fit down the stanchion. Because the SeaTalk1 cable provides power, we no longer needed the separate power cable and removed it.

The SeaTalk1 cable is attached to a small block that just allows another SeaTalk1 cable to be plugged in. That then connects to the SeaTalk1 to SeaTalk NG Converter. This block converts SeaTalk1 to SeaTalk NG (which is the same protocol as NMEA 2000, but with proprietary connectors). This then has a cable that has a SeaTalk NG connector on one end and NMEA 2000 connector on the other. This connects to the NMEA 2000 backbone. As soon as this was connected, the chart plotter started showing wind speed, wind direction, and depth. This info was also passed to saillogger, so shows up on the monitor page.

Achernar Wiring Block Diagram

The other end of the NMEA 2000 backbone runs into the cabin. This is connected to the Standard Horizon GX6000 VHF. Although the radio has an AIS receiver (but not transmitter) built in, we are not using it, instead using the West Marine AIS 1000 transceiver that came with the boat. (For the last five years Standard Horizon has described a GX6500 model that has an AIS transceiver built in, but the rumor is they have had trouble getting it certified by the FCC.) While we could receive AIS on the GX6000 and transmit with the AIS 1000, we run into a little problem with the antenna.

On a sloop sail boat, you only have one mast, but you need two antennas: one for VHF transmissions and one for AIS transmissions. They need to be separated by several feet. On a power boat, you can just fix two antennas to the top of the cabin in different places. On a sail boat, the workaround is something called an antenna splitter. You put up one antenna, but plug the VHF and the AIS into the antenna splitter and connect that to the antenna. (It can also handle AM/FM.) VHF is considered a safety system. If you push the DSC panic button, you cannot have the AIS transmitting, so when the VHF is being used, the splitter gives it priority. But if you have two AIS units, you will need two splitters, which would theoretically work, but asking for trouble. (Why the GX6000 doesn't have an antenna splitter built-in is a mystery.)

Instead, we just ignored the fact that the radio has an AIS receiver and used the West Marine AIS 1000 transceiver that came with the boat. That came with its own can of worms, the first of which was that we changed the MMSI associated with the boat. The MMSI that came with the boat was likely issued by BoatUS or the US Power Squadron. These free numbers only work in the United States. We plan on going to Canada on our boat, so the MMSI needs to be issued by the FCC. An FCC MMSI (which you can identify because it ends in zero) is exchanged with other countries, including Canada. This allows you to push the DSC panic button in Canadian waters and the Canadian Coast Guard will come rescue you. We applied for and received our new MMSI.

However, the FCC does not let end users of electronic equipment arbitrarily change the MMSI on equipment. Our new radio lets you put the number in once, but you have to send it back to Standard Horizon to change it thereafter. Our West Marine AIS already had a MMSI inputted, so it could not be changed. We contacted West Marine, but of course they are not the manufacturer, no longer sell it, and don’t really support it any more. West Marine emailed back some minimally helpful information that eventually led to getting it changed.

The wiring in the garage. Not as beautiful as we would like, but better than it was.

The next challenge was that for the chart plotter to get the AIS info. We needed the AIS to be on the NMEA 2000 network. That is all well and good, except the AIS 1000 only does NMEA 0183. We bought a Digital Yachts iKonvert unit that converts 0183 to 2000. While relatively expensive, it still was much cheaper than buying a new NMEA 2000 compatible AIS transceiver. The iKonvert little box has a NMEA 0183 connector on one side and a NMEA 2000 connector on the other. There are also DIP switches that control what messages should get passed through and the speed of the connection, which we set to AIS and GPS transmitting at 38400 baud. As soon as it was connected, the AIS info from other boats started showing on the chart plotter. A friend confirmed that we were transmitting our location, but that was always working.

But then a new problem started happening: The chart plotter was getting GPS info unreliably. The AIS 1000 has its own GPS antenna, separate from the one on NMEA 2000 network. The iKonvert was passing GPS info through from the AIS 1000 to the NMEA 2000 network, and the Garmin 4212 chart plotter was prioritizing the AIS 1000 GPS info. For whatever reason, this info was coming through intermittently and causing an error. We finally found the setting in the chart plotter to prioritize the Garmin X17 GPS antenna, which solved the problem.

We mounted the external connection for the RAM4 microphone on the port side, just below the propane locker. The boat came with about an inch diameter of broken fiberglass at exactly this spot which needed to be repaired, so drilling it out solved two problems. The one drawback to this location is that the aft locker door will run into the microphone if it is fully opened. So we will be attaching a cable to limit the distance the door will open by a couple of inches.

The last thing we needed was for the Raspberry Pi that saillogger runs on to have a reliable Internet connection. For that we acquired a Galaxy pad A7 Lite with a SIM card from T-Mobile. This runs a wi-fi hotspot that the Pi connects to. The monthly cost is relatively cheap, and the device was free after paying tax and a connection charge.

All of the equipment is now connected and working. Our next step is to make it all pretty, but that’s a topic for another day.


Don't Use 5200 On Your Boat

This is going to be a rant about 3M Marine Adhesive Sealant 5200 and why you shouldn't use it on your boat. If you are not a boat builder, you have no reason to use it. The problem is that 5200 creates a permanent bond between two surfaces. There is that word "permanent". What, exactly, is permanent on a boat? Is a port-light permanent? Or a winch? How about combing? A stanchion? A bow roller? None of these are permanent. All of them will need to be serviced and replaced at some point. It might be 10 years, or it might be 20. If you use 5200, you, or the person who eventually owns your boat, will swear at that idiot who used 5200.

Okay, there are a few reasons to use 5200. If you are putting a new thru-hull below the waterline, that might be a reason. I think we used 5200 to fasten down the mast step on our Catalina 22 that was loose because that has a seriously long lever trying to pry it up from the deck. But almost anything that you think you should 5200 for could also be done with 4200 or even 4000.

Some people will use debonding agents, or have a scheme with a guitar E string for getting 5200 separated. But why do that when you could have used 4200.

Captain Boomies did a cool demo on why 5200 is the wrong product for anything you can think of on a boat. When you think of something that you might want to use 5200 on, ask yourself "can I use 4200 or even 4000 for that thing".


Installing the Raspberry Pi and Using Saillogger

A new addition to our boat is the ability to log all of our travels. To do so, we added a Raspberry Pi powered by the boat's 12V system, connected to the NMEA 2000 backbone, and running a program called Saillogger. See our article on boat networking.

We started by buying a Raspberry Pi. This is a single-board small computer. It has most of the functionality of a large desktop on a tiny board. The specs: 1.5 GHz 64-bit quad core ARM Cortex-A72 processor, on-board 802.11ac Wi-Fi, Bluetooth 5, full gigabit Ethernet (throughput not limited), two USB 2.0 ports, two USB 3.0 ports, 8 GB of RAM, and dual-monitor support via a pair of micro HDMI (HDMI Type D) ports for up to 4K resolution. It runs a version of Linux.

Raspberry Pi 4 B

The Raspberry Pi then has added the PICAN-M hat board. This plugs into it and provides NMEA 2000 and NMEA 0183 connections, as well as providing power from the NMEA 2000 connection. It takes in 12V and steps it down to 5V.

PICAN-M hat board that plugs into the Pi

This entire setup is then enclosed into a nifty little case. It is about the same size and somewhat thicker than a pack of playing cards.

Case for the Pi, plus the PICAN-M

You can test the whole setup by using a micro HDMI cable, monitor, USB keyboard, USB mouse, and either a wired or wireless Ethernet connection. The Pi will need a micro SD card. If you want to power the board at home for testing purposes, you will need a 120V to 12V converter to power the NMEA 2000 backbone. You may also need a USB adapter for your computer to transfer the operating system onto the card. We did all our initial setup at home, then moved to the boat where we remotely log in using a laptop via WiFi with both devices connected to a phone hotspot.

Our setup required that we pull a NMEA 2000 backbone cable from the "garage" lazerette where our existing backbone was located to the panel to the right of where the AC/DC distribution is located in the cabin of the Catalina 320. The boat's existing cables feed above and behind the cabinets in the galley. We unscrewed the wood panel on the rightmost cabinet, then easily used an electrical fish wire to pull it from the garage. (Make sure to disconnect from shore power before doing this as there is live AC back there.) This is then fed down behind the AC/DC panel. Power is provided by the 12V on the NMEA 2000. We already have a Garmin 17X GPS antenna on the boat hooked to the backbone to feed GPS info to the chart plotter. We put a "T" on the backbone and installed the terminator. Then we attached a drop cable to the PICAN-M NMEA 2000 socket. This kit will provide all the basic NMEA 2000 hardware.

We installed the Debian and SignalK software onto the Pi. We found this page provided really excellent instructions on the install. If you are not familiar with Linux, you may need a friend to help you. We then installed Saillogger.

Sailogger is a program written by a friend of ours. It consists of two parts: a program installed on the Raspberry Pi through SignalK and a web site to which it uploads the information. It automatically records every time you leave a marina and where you have gone, pulling the info from the GPS (and other devices) on the NMEA 2000 network. The next time the Pi gets an internet connection either through a marina wifi or a phone hotspot, it uploads it to the Saillogger web site. There is very little configuration necessary and virtually no information that needs to be added to the logs. You don't need to remember to start something or end it...it is all automatic as long as the NMEA 2000 backbone is powered.

After installing it, we went out for a day sail on Lake Washington.

One image from the Sailogger upload

Detail of performing Man-Overboard drills


Cutting Board for Stove Top

We found a perfect cutting board to go onto the stove top of the Seaward Hillerange Model 2172 stove that came with our 1994 Catalina 320. It is a Bisetti Walnut cutting board. If the front bracket wasn't on the stove top, this would drop right in. However, we needed to pry the Bisetti logo off the front (it is a friction fit into two holes, so comes right off), then sand it down where the bracket and screws on the side goes. Then we applied some food grade mineral oil. It is a beautiful addition to the galley. The board has two sides, one with a groove, and either side can be up.

To hold the board perfectly level, we added two brackets to the lower screw on each side of the front fiddle. These are Everbilt 547 475 one inch stainless steel corner brackets. We lightly filed the corner so it wasn't knife sharp.

Cutting board
Corner that had to be sanded down
L Bracket to hold up edge


ASA Certification on a Bavaria 41

Most places that you charter a boat, you need to get a certification to show that you are qualified. The two organizations that provide the the most widely recognized certification organizations in the United States are US Sailing and American Sailing Association (ASA). Our plan was to get our certifications so we could fly somewhere else, such as the Caribbean, and charter a boat there.

Just before Covid hit, we were on our way to getting certifications with US Sailing, having completed our Basic Keelboat certification. Covid put a hold on completing the certifications. When we decided to upgrade our own boat, we were initially looking at larger boats, but we chose to go somewhat smaller at 32 feet to leave budget to charter boats elsewhere (and budget for upgrades, as well). As we revisited certifications this year, we found an ASA course that met our needs. We booked a week-long trip through San Juan Sailing that covered ASA 101 Basic Keelboat Sailing, ASA 103 Basic Coastal Cruising, and ASA 104 Bareboat Cruising. This allows us to charter monohull boats up to 45 feet anywhere in the world.

San Juan Sailing has a fleet of about 60 boats mostly sailing out of Bellingham, Washington. We got booked onto a three-cabin, two head, Bavaria 41, Fresh Aire. The cruise had five crew: Sandi and Greg, Mark and Jessica, and the instructor, Bob. Bob has been sailing for 30 years and knows his stuff. Mark and Jessica have been power boaters on lakes and rivers, but are new to sailing.

The Bavaria 41, Fresh Air Mediterranean docked at Stuart Island.
The course ran from Saturday, July 9 to Friday, July 15, 2022. We checked in by 11 a.m. and brought our stuff down to the boat. The first test was finding all of the safety equipment on the boat. We drew straws for cabins, and got the starboard aft cabin. This cabin has the feet at the aft of the boat, which turns out requires more gymnastics than the aft cabin on the Catalina 320 that has the feet pointed at the port side.
San Juan Islands
(by Pfly, CC BY-SA 3.0)

Saturday, July 9: We got lunch ashore, then prepared to leave dock. Our first stop was Sucia Island, on the north side of the San Juan Islands. We left the marina in Bellingham and raised sail, headed north of Lummi Island. At Sucia, we tied up to a linear mooring system in Echo Bay and spent the night.

Sunday, July 10: We sailed to Stuart Island and Mediterranean docked. We hiked to the T-shirt place.

Monday, July 11: In the morning, we did docking training against the line linear docks at Stuart. We sailed to Roche Harbor and docked at the marina.

Tuesday, July 12: We sailed all the way around the south end of San Juan Island, up the east side of Shaw Island, and anchored in Blind Bay. The seas in Harro Strait were four feet. Winds in San Juan Channel were 29 kts sustained, gusting to 32 kts. Sailed very reefed in using the furling mainsail and genoa.

Wednesday, July 13: We sailed to Rosario Resort on Orcas Island and docked at the marina.

Thursday, July 14: We sailed back to Bellingham and docked at the marina. We refueled and pumped out, performing docking training.

Friday, July 15: We did some docking practice in the marina in the morning.

All in all, a successful week. We learned some new techniques and got much better at sail trim. We got a lot of docking practice in. We did lots of man-overboard drills. These drills are not just good for emergencies, but practice in handling the boat.

Sandi at the wheel


Boat Networking

This is a brain dump of what I've figured out about boat networks.

There are devices on a boat that need to talk to each other, needing protocols and physical connections. This is on a boat which is a physically demanding harsh environment. There is little space, frequently not easy wiring runs, sharp corners (both radius and cutting), and salt water and salty air. They are making some wireless devices now, but I don't trust them to provide a reliable connection in wireless saturated areas (and near military bases), and you still frequently have to get power there anyway so you still need wires.

There are some industry standards:

On our boat, we have to deal with another proprietary physical connection/protocol called Raymarine SeaTalk 1.

The NMEA 0183 physical connection is essentially a RS422 serial connection (an old computer standard that was used to connect computers to modems, among other devices). It is point-to-point...two devices that want to talk to each other need two wires running between them, but one transmitter can have several listeners. While this standard is obsolete, it is still used in many older devices, and newer devices sometimes still support it for backwards compatibility. On Fantasia, we used NMEA 0183 to feed GPS data from the chart plotter to the VHF radio. If you hit the DSC (Digital Selective Calling) panic button on the VHF radio, it would transmit the GPS data to the Coast Guard in a digital format, broadcasting the MMSI (a primary key number into a Coast Guard boat database) and GPS coordinates and saying "come get me". The protocol is expressed essentially in text "sentences" like $GPAAM,A,A,0.10,N,WPTNME*32. It is very low bandwidth, 4800 baud normally. You must run an extra two wires for power, so normally there are four thin wires between devices.

NMEA 2000 is essentially CAN Bus, a standard used in cars, airplanes, and manufacturing. There is a backbone cable that stretches on the boat that is terminated on each end. Various devices plug into this backbone cable, and the drop cable going to the device can be 27 feet. The protocol is 8 byte packets. Most devices produced in the last 10-20 years use this protocol. Bandwidth is 250kbs--good enough for most data, but not for radar/sonar/video. It has power up to 25 watts per device on the wire.

Example of a NMEA 2000 backbone similar to ours.

Our NMEA 2000 backbone on Achernar is literally about 1 foot long (this will be changing soon), with the drop cables running to different points. As we bought Achernar, there were three drops to the NMEA backbone: 12V power in, a Garmin 17X GPS antenna, and a Garmin 4212 chart plotter. Significantly missing is information from the West Marine 1000 AIS transceiver, which has NMEA 0183 (only) output that currently goes nowhere.

NMEA OneNet is essentially Ethernet, with a custom protocol sitting on top of IPv6. The standard took about 10 years to produce, and was published about two years ago. As near as I can tell, no manufactured devices actually use it yet. It should be able to handle radar/sonar/video. It does power with PoE (power over Ethernet), with all the strengths and limitations that has.

The wind, depth, speed over water, water temperature, and autopilot on Achernar don't use any of these to communicate to the displays at the helm...it uses a proprietary protocol called Raymarine SeaTalk 1. (This is not to be confused with SeaTalk NG or several other similarly named protocols. SeaTalk NG is a rebranded NMEA 2000 using proprietary cables.) The details of this SeaTalk 1 have been reverse engineered. You can get SeaTalk 1 devices to talk to a NMEA 2000 network by converting SeaTalk 1 to SeaTalk NG, then connecting SeaTalk NG to NMEA 2000. With this translation, we should be able to see wind, depth, speed, and water temperature on the chart plotter without having to replace all the devices.

Sometimes you want to get the info on the NMEA 2000 backbone in a format that can be interpreted by a computer. With OneNet, that would be easy, you just get a device driver for the OneNet packets, but with NMEA 2000, that's trickier. There is a device called iKommunicate that convert NMEA 2000 packets into Ethernet packets. It basically plugs into the NMEA 2000 backbone and dumps out Ethernet packets in HTTP SignalK format on an Ethernet port. (It also accepts a couple NMEA 0183 devices.)

SignalK is an open source JSON protocol for understanding NMEA 2000 data. The output from the iKommunicate device can be fed to the Ethernet input on a computer or a Raspberry Pi. There are various programs that interpret the SignalK format and produce displays of instruments and log where you have been. Another alternative is there is hat board that fits onto a Raspberry Pi unit called PICAN-M. This board performs the same task as iKommunicate, except it only works with a Raspberry Pi.

Our friend Ilker has written a Signal K logging program that's pretty nice: https://saillogger.com. I will write up our use of this program later.

Our Garmin radar uses an Ethernet cable for talking to our Garmin chart plotter. The cable is run point to point from the radar dome to the chart plotter. It uses a proprietary Garmin protocol.


Opening Day Raft-Up

Tyee Yacht Club raft up. We are the third boat from the left...the small one.

Only three days after making our way down from Anacortes, we headed back out to join Tyee Yacht Club's raft-up at the Montlake Cut for Opening Day. We tied up with 13 other boats (two more joined after the photo was taken) just north of Marsh Island at the Seattle Arboretum for five days. Opening Day is the official start of Seattle's boating season. On the north side of the cut is a log boom where hundreds of boats tie up. We tied up on the south side where only the yacht clubs get to tie up. Pot luck dinners, drink, and other events happen on the boats.

It was cold and rainy most of the days, but brightened up just in time for the boat parade down the cut.


The Voyage South

We began our adventure travelling south toward are new slip in Kenmore. Our slip became available on May First, so although we could be faster we decided to take advantage of our time. We headed down the west side of Whidbey Island and across the eastern end of the Strait of Juan de Fuca. This area can be extremely rough if the conditions are not good, but on this day, the weather was perfect. The water was glassy. The boat was running well.

The worst seas we saw the entire trip

We pulled into Tyee Yacht Club's virtual outstation at Port Hadlock. It's called a virtual outstation because there are no dedicated docks for the club, but they will do their best to fit you in. We got a slip on their newly refurbished dock. They have done a great job upgrading the docks. New LED lighting, new power stations, and a pump-out at every two slips. Using our club membership, the cost was free!

The next morning we headed down to Tyee West Outstation at Eagle Harbor on Bainbridge Island. We joined 20 other boats for the 75th anniversary of the club. We rafted to another boat for the night and joined the pot luck that night.

Headed through the small lock

The next morning we headed off toward our dock. We have to come in through the Hiram Chittenden locks into the Lake Washington Ship Canal. Our friends that we were tied to at the outstation were right in front of us. After getting through the locks, we had the privilege of screwing up all of Seattle traffic as we made them open four of the bridges as we move through the canal. On the 22, the only bridge we needed opened was the Fremont bridge, and even then, it's only by inches. With the 320, we need them all open as most have 45 feet of clearance, and our mast is 50 feet with the antenna.

Raising the bridges

We finally got to our dock, only to find it still occupied. We tied up in temporary space and made a few calls to the after hours number for the harbormaster. Some people eventually came out and moved the boat and we could pull into our slip for the next year. The advantage of this slip is that it is five minutes from our house, so coming down and working on the boat is easy and we can go out for evening sails easily.

The weather window was just perfect, which was really good because we were sailing on a schedule. You never want to be sailing on a schedule! The weather sucked before and it sucked after, but we had three days of sunshine and calm seas.



We have renamed our Catalina 320 to Achernar. Achernar is pronounced ay-ker-nar, with a long A sound. It's name comes from Arabic, which means End of the River. It is named for the last star in the constellation Eridanus, which is the River constallation. As a .5 magnitude star, it is the ninth brightest star in the sky. Because it is a southern star, it is currently visible only below 33°N, a little south of Los Angeles. It is a blue star, and is currently the flattest known star in the Milky Way, spinning so fast that its equatorial diameter is 35% greater than its polar diameter. Eridanus is a river of stars that heads south from near Orion's left foot. It ends at Achernar, the end of the river.

The boat name shows the stars of Eridanus, meticulously recreated in software by a program Greg wrote. The font is Decotura ICG, the same font we used for the name on Fantasia.

Achernar shows up in popular culture in several contexts. It was Jack Vance's favorite star. It showed up in many of his works, but particularly in The Dying Earth, the creature Firx came from Achernar. In the Star Trek universe, the planet Romulus, home world of the Romulans, circles Achernar. Vulcan is also in Eridanus. Our theme song is Achernar, by Carlo Whale.


Dripless Shaft Seal Installation

We began our trip moving the boat from Anacortes to Kenmore. The first step, though, was to take the boat out for some upgrades. We motored from Cap Sante Marina to Skyline Marine Center on the other side of the peninsula. It's only about 4 miles on land, but about 12 nm by sea. It took us about two hours. We backed into a dock using our new docking skills, then got hauled our and placed on the hard at their DYI yard. There, Fathom Marine installed our new dripless shaft seal.

Boats of this generation come with a packing gland. This is the material that keeps water coming into the boat around the propeller shaft where it enters the boat. Except a packing gland has to let some water into the boat, because it also acts as the lubricant, keeping the shaft from overheating. This puts a constant amount of water in the bilge. This means the boat always has moisture in it, which leads to mildew and other problems if not controlled. A dripless shaft seal uses a different mechanism for lubrication, meaning that no water needs to enter the boat from the shaft. They are not terribly expensive, but there is the labor and the boat must be hauled out.

While doing our docking training, we noticed the transmission was having quite a bit of trouble going into gear. Eventually, we discovered that the idle was set too low for our Perkins engine. The correct idle was buried in the Perkins manual. When bumped up to 1000 RPM everything worked just fine. This is faster than most engines, but the transmission just does not work at a slower idle.

Adding our new boat logos

While the boat was hauled out, we took the opportunity to lubricate all of the thru-hole valves. We also removed the remaining boat name, home port, and Washington State ID number. Our boat is Coast Guard Documented now, so should no longer have those numbers on the bow. We then added the new boat name and home port.

The boat was then dropped back in the water. We took advantage of our reciprocal moorage with Flounder Bay Yacht Club to stay there at Skyline for two nights, while we got all our ducks in a row for the voyage south.


Docking and Maneuvering Training

We decided we needed some additional training on docking. On the 22, docking is not terribly difficult. Greg could stop the boat just by holding the bow pulpit or stanchion. But with the 320, trying to stop a 11,700 pound boat under diesel power just doesn't work the same way.

Shearwater University is a US Sailing instructional group run out of Cap Sante Marina in Anacortes. Their slip for Ardenna, their sail boat, was only about 40 feet from our slip. We ran into them several times while doing work on our boat. They do training on your boat, if you like. So we contracted to have Mark go out with us and give us some docking and maneuvering training. The night before, we had them help us get the boat turned around and moved to an easier slip to get into and out of.

The morning of our training we went to Fisheries Supply and West Marine and bought two Shaefer mid rail cleats and two 5/8" 35' docking lines (later adding two more). The mid rail cleats slide onto the 1.25" tracks, which takes no effort at all to install. Although the cleats were expensive, when you factor in time to install permanent cleats, they were cheap.

Shearwater teaches a single line docking technique. It's pretty slick. It's designed for having one pilot and one crew. It needs to be modified a bit for different conditions, depending on the wind direction and whether launching forward or toward the aft, and which side your prop walk takes you. For launching, essentially the scheme is to have the engine push against a single spring line at midship that is looped around the cleat and back to the mid rail cleat. Then all the other lines can be removed. With the wheel turned, that one line will pull the boat into the dock. The mate comes on board. The boat can then be put into neutral, the spring line untied, the boat put into gear, the spring line unlooped from the dock and you are underway.

Coming in, the mate goes onto the dock with the spring line. It is looped around a cleat but not locked. When the boat is at the right place on dock, it is placed into neutral. The spring line is locked. The wheel is turned and placed in gear at idle speed. The boat sucks right into dock and held in place by the single spring line. Now at leisure the entire boat can be made secure with forward and stern lines. Then the engine is shut off.

Docking with these techniques is so much less stressful. We put it to use immediately and with just a little practice it is working very well. There is only one step in docking and launching that has to be timed well, which is getting the spring line on and off the cleat. The rest can be done at leisure. Nobody is jumping on to a boat that is leaving the dock, which is much safer.


Out for a Test Sail

We took the 320 out for a test sail from Cap Sante Marina in Anacortes. The dock we were on is tricky, as it is in a narrow channel that is affected by the tides and there were other boats on the parallel dock. Still, Sandi took her out smoothly. We got her out in the bay. After testing motoring for a bit, we noticed the transmission was not quite reacting the way we'd like, being stiff and not wanting to go into gear. We brought out the jib, and shut the motor off. On the first tack, the jib knocked one of the spreader boots off, which landed on deck. Our rigger had said they were old, but thought they'd last the season. The spreader boot acts as a cap on the end of the spreader that keeps the sail from getting snagged and ripping. It's kind of important to have.

Underway for the first time since the sea trial

We decided not to bring the main out, partly because we had the Dutchman system only partly connected. We still needed the backstay for that, which we had on order. The Dutchman is an interesting alternative to lazy jacks. There is a filament that is threaded through the sail that goes from the bottom to the back stay fastened from a halyard at the top of the mast to the end of the boom. The filament attaches at two places on the backstay. When the sail is dropped, it flakes itself on the filaments. This Dutchman was original to the boat, but the filaments were broken and the backstay was nowhere to be found on the boat. We had taken the sail into Doyle sails in Seattle. They replaced the filaments, as well as adding a second reefing point and replacing the slugs that hold the sail to the mast. Four of the slugs were broken when we bought the boat, but they all needed to be replaced.

After being out for a short time, Sandi expertly piloted her back into our dock.

In the next several days, our rigger, Kent Morrow of North Sound Rigging, went up the mast and replaced all of the spreader boots. He also replaced all of the lifelines that were at end of life.


Boat Maintenance

We took our Catalina 320, currently named Skål, out for our first time away from the dock since the sea trial. We will get to that in another post, but we've been busy for the last six weeks. We have had engine maintenance, sail maintenance, and other general work to get her ready to go. Our first issue was getting her insured. We went back to BoatUS, who has been our insurance company on Fantasia. They looked at the survey that had been done, picked what seems like an arbitrary four things that had to be fixed before they would insure the boat. Not only did we have to fix them, but we had to have our surveyor come back out and verify they were fixed. So we did.

Out of the things on the survey, they decided that we had to replace the exhaust hose, fix the bilge pump hose, stop a really minor deck leak of the port mid-ship stanchion, and put some chafe guard on some engine water hoses. Other things like a dead carbon monoxide detector didn't matter to them, which I'll come back to in a bit. The exhaust hose was at end of life, but really didn't need replacing before insuring the boat. But fine. We got 20 feet of exhaust hose (we needed maybe 12) and replaced it. We rebedded the stanchion, which was relatively easy except getting access to the nuts inside the boat was tricky. The chafe guard on the hoses took minutes to fix. The bilge pump hose had a minor split that needed repair, which we did. We would have got to all of these, but probably with a different priority if the underwriters hadn't chosen the priority for us. We could have chosen a different insurance company, but we were going to fix them anyway.

The mainsail was missing four of the slugs that hold it to the mast. So we took it in to Doyle Sails and had them fix that, as well as add a second reefing point on the sail. We also had the Dutchman system on the sail repaired as the filaments were broken. The gate that allows you to remove the mailsail from the mast was installed with non-stainless screws, which had rusted and caused their heads to break off. We had to drill them out and re-tap them. Do not use hardware that isn't stainless on a sailboat!

The Perkins M30 engine the boat comes with was running rough, so we had Darrel at Fathom Marine Services do some overdue maintenance. The M30 has a notorious problem that the exhaust elbow part gets clogged with carbonization. Sure enough, it was bad enough that the part had to be scrapped and a new one ordered from England and expedited out. (If you have an M30, get the elbow checked!) We got all the fluids changed, the timing on the engine fixed, and the idle changed, replaced the impeller, etc.

We had Kent from North Sound Rigging come out and do a rigging inspection. He mainly noted that our standing rigging and lifelines are at end of life. You are supposed to replace the standing rigging every ten years, and ours are 28 years old. Still, there was nothing that looked terribly wrong, so we are scheduling that for this fall. The lifelines, though, will get replaced earlier. He also noted that the shroud boots needed replacing, two cam cleats on the traveler was dead (we had already noted that and replaced them with new Harken cleats before he gave us the report), and a few other items. Basically we need standard rigging maintenance, but nothing that said don't sail.

We could have had the rigging inspection required before buying the boat, but we didn't feel that anything he would have to say would change what we decided on the boat, just what items were on the list.

We replaced a bunch of outdated or dead safety stuff on the boat. The flares were from the 1990s. The fire extinguishers were old, too, and certainly don't meet the new Coast Guard specs that come into play this month. We replaced those. We replaced the dead carbon monoxide detector in the salon with a new Kidde smoke and carbon monoxide detector. We added a second one to the aft cabin where there had never been one. We replaced the dead GFCI AC sockets. Why weren't these things weren't important to the underwriters?

We replaced all of the interior incandescent lights with new LED lights that are both brighter and use less battery. We added labels to the electrical panel. We added a wire tie to the macerator to make it so it can't be opened in the Salish Sea. We fixed the handle on the head door. We replaced the wing nuts on the battery terminals with regular nuts, and found one of the battery terminals had cracked, so replaced that. We topped off the water in the batteries. We added Froli bed springs to the bed in the aft cabin. We replaced the cover to where the emergency tiller attaches because the handle was broken.

As noted on the survey, the drain on the propane locker was clogged. This is important because it is the exit point from the boat if the propane tank leaks. You don't want propane on a boat because it tends to go boom! Except you need propane on a boat to run the stove. So you isolate it and make sure that any leaks go overboard rather than sinking into the bilge where a spark causes bad things to happen. A clogged hose leaves propane on the boat. We replaced that hose (43" of 1" hose), also finding that there was a screen placed at the end of the hose to keep bugs out that had been completely clogged with debris. We removed that screen.

We have an Ardic diesel heater on the boat. The unit is in the starboard aft lazerette. This pumps out a ton of heat. Unfortunately, there seems to be a leak in the exhaust, because it caused the brand new carbon monoxide detector to go off at 1 a.m. If we hadn't installed that in the aft cabin, it literally could have killed Sandi. We have since added a third carbon monoxide detector in the lazerette next to the heater. If there is one thing the underwriters should have insisted on was new detectors. We haven't fixed the heater yet, but we aren't running it until we do. Since we are at the marina, we are using an electric heater for now.

None of these things are surprising on a boat. Every boat has a list like this, even brand new boats. (We use Microsoft To Do to maintain our lists, which allows modifying them from any device.) We just are doing all of this stuff at once rather than stretching it out. We learned so much doing work on Fantasia, our Catalina 22, that prepared us for taking on this boat.