Latest News

Welcome to MV Tanglewood. Please fill out the "Follow this blog by email" (to the right) to receive notifications of updates to the blog. Thanks, and enjoy!

Tuesday, March 24, 2015

More on NMEA 2000

In the comments for this blog entry on NMEA 2000 we have been having an interesting debate about whether the NMEA 2000 glass is half full or half empty.  I remain a proponent of N2K, but continue to run into implementation problems that are real spoilers.  This stuff just doesn't appear to be tested enough against the basic standards requirements, or for practical interoperability across vendors.

I remember back when I was building networking products there used to be industry plug-fests to see how things worked together.  My wife was really concerned about what a "Plug-Fest" might really be about, but she knew we geeks weren't that imaginative.  So for a few days all the industry's competitors would put down their guard and all meet up in a hotel somewhere loaded with equipment.  There was a schedule where the vendors would go from room to room like honey bees pollinating flowers, except they would be trying their equipment to be sure it worked together.  Everyone knew that their product success depended on working properly with other vendors, even though we all preferred that everyone buy everything from us.  Everyone also knew that a customer's site was NOT the place to discover and debug problems.  It worked and UNH even created a networking interoperability lab that vendors still use to this day.

Dial forward to my last company, EqualLogic, where we were among the first people to use a new standard for data storage over networks.  Our lives depended on that standard working, and on our products working with everyone else out in the market.  And to complicate matters, we were dependent on a somewhat obscure feature in the standard that very few people planned to use other than ourselves.  This feature was mandatory in the standard, kind of like Instancing in NMEA 2000, but we expected many people would not implement it, or not test it, and if it didn't work, we would be the one to suffer.  So we made a point of reaching out to every single vendor who we could find who was working on this stuff, educated them on the feature and how it was important, provided consulting to whatever extent they needed it, offered to test with them to be sure we worked together, and ultimately provided customers with a list of products that we knew we worked with.  It turned out very well.

Now let's come back to the latest with N2K.  Our electronics are all done and we left yesterday to go cruising.  I powered everything up, including the autopilot, and all was well.  Then I turned on the VHFs and right around then the autopilot alarmed saying that my heading source had changed.  I have two sources, a sat compass and a rate compass, and the pilot is programmed to use the sat compass first, followed by the rate compass if needed.  I checked which was currently in use, and it was the sat compass just as it should have been.  Hummm, weirdness strikes again.  I brushed it off and moved on.  Well, over the course of our day it alarmed about 6 times.  Each time I cleared the alarm and checked to see which compass it was using and it was correctly on the sat compass.

We made it to our destination and, got settled in to our slip, and went out to explore.  The VHFs were off, but I left the pilot on to see if it would alarm again.  It didn't.  After dinner I decided to try a little experiment, and I turned the VHFs on again.  Guess what?  The pilot alarmed right away.  WTF, right?  So I broke out the analyzer and started looking at the data stream coming from the various devices.  What I found was a storm of traffic every 10 seconds.  The bus was going through an address claim process every 10 seconds, followed by everyone querying everyone to gather basic info.  This is a normal process, but should only happen when there is a configuration change in the network, and it should only happen once.  Things should then remain stable until there is some other change in the network, like powering on the VHFs.

These storms of traffic last for a second or two then settle down, and the storm gets bigger the more devices there are on the network.  My working theory is that adding the VHFs pushed the storm size to the point where the pilot was occasionally missing enough heading report messages (it expects then 10 times a second) that it briefly declared the heading sensor dead, but then healthy again before I could even ack the alarm.  I've had issues just like this in the past, and as soon as the trigger for the storm is removed, all the problems go away.  I had chased down one cause for such storms and gotten it fixed via a firmware update, but now here it was again.

I've been digging into it today, and think I've traced it down to a request from one device that is obscure and arguably unexpected, that triggers a second device to request the address claim process and that sets off the storm.  Take away either of these two elements and the storm disappears.  And this may actually be brought on my yet a 3rd device that when first powered on correctly responds to the obscure request, but after being on for some number of hours or days seems to stop responding, possibly causing the requester to become more insistent.  The part that's clear is the ongoing address claims being requested by one device.  What's a little less clear is exactly what's triggering it.

The point is that it's all this tangled mumbo jumbo that leads to the simple complaint that "my auto pilot keeps losing heading", and customers and installers tearing their hair out trying to figure out why the VHF is messing up the autopilot, and vendors pointing the fingers at each other.  It's only when you take a look with an analyzer that you see something is really amiss.  Most boats would never know if they had such a problem brewing, yet would experience occasional "Gremlins".

My advice to vendors?  Go Get a Room and plug away.

Thursday, March 12, 2015

Radar comes to life

Chris from Performance Marine has been here for the past two days helping finish up my refit.  Progress has significantly picked up as a result.  Yesterday we got the gigantic radar cable pulled through the boat and up the stack.  Now that was a struggle.  The cable is at least an inch thick and had to fit through some places where I never thought it would fit.  Then Chris spent the afternoon mounting both radar scanners and connecting up the cables.  Meanwhile, I continued to wire up the autopilot and fish finder.

Radar scanners going up

Scanners going up

Scanners going up
Today we spent the day wiring things up.  AIS to FAR2117 radar, AIS to 1835 radar, heading sensors, GPS and other navigation info, etc, etc,  We have a lot fewer ring terminal connectors than when we started.  But all the wiring was worth it.... because now we have two operational radars.

Here's the 12kw FAR2117.  It looks great on the monitor even though it doesn't fill the whole screen.  I haven't made any adjustments and we have a few things to tweak, but all in all, it looks great.

Radar power up

Here we are with the scanner active.  Behind us is the ship canal, and we are otherwise surrounded by boats and buildings.

Viewing the ship canal behind out boat

Oh, and the fish finder works.  Tomorrow we button up loose ends and get the auto pilot running.

Saturday, March 7, 2015

New dash panel

The last major piece of equipment, the FAR2117 radar, arrived yesterday.  With all the parts on hand, I was able to finalize the layout of the dash panel and get all the components cut in.

Here's everything laid out with templates and marked up.  The round hole is from one of the old autopilot controllers and will house one of the new ones.  And the rectangular hole all the way to the left is from the FLIR controller.  I'm not moving it, but I temporarily removed it to make cutting the panel easier.  What you can't see behind the blue tape are all the other holes from previous equipment.  I lucked out and was able to arrange the new devices in a way that uses and/or covers all the old holes.

Marked up locations for new devices

 Here's everything cut out.  The hole furthest to the right shows a blend of old cutout and new cutout.

Holes cut for new devices

 And here all the devices are installed in their new locations.  This big panel is for the FAR2117 radar.  Then working to the right are dual auto pilot controller followed by the FCV627 fish finder

New devices all installed
I've also been pulling various wires and cables in preparation for hooking everything up.  That will be the focus from here on out.

Friday, March 6, 2015


Nordhavn does a really good job on nearly all aspects of their boat builds, but like all manufacturers, there are a few "what were they thinking" features.  The ship's horns are a good example.  Yes, they are Kahlenbergs, but they are the smallest whimpiest model they make, and rated for boats up to 30' or something like that.   And they make more of a quack than a honk.  Upgrading has been on the list, and was finally triggered by the radar upgrade since the new open array would whack into the old horns where they were located.  So last month I removed the old horns and sold them, and just received the replacements.

Step one was to replace the air compressor and air tank.  The new horns need more air than the old ones, so the whole system needed to be replaced.  This was also a great opportunity to convert from a 12V compressor to a 24V compressor.  It was really silly that the boat was set up for a 12V compressor since 24V makes much more sense for a heavy load appliance like this.  It was a bit of a pain to move the circuit in the breaker panel, but worth while.

Here's a picture of the new compressor and air tank.  They live under the fly bridge settee.

Air compress under fly bridge settee

Air compressor

Air tank under settee

Air tank

Today I hung the new horns and finished the air line plumbing and wiring.  Access into the stack can be very difficult in certain areas.  I had to borrow this ladder to access a removable louvered panel on the back side.  Through that I was able to attach the solenoid air valve, pipe fittings, and wiring.  This access panel was also the key to finally getting the old radar cable out, and will be instrumental in fitting the new one.  I'm slowly getting more comfortable with the heights involved in all this.

New horns

Rearranging the mast top

The arrangement of poles and instruments at the very top of the stack is called the "stinger".  Or at least that's what I call it, mostly because I heard someone else call it that and I thought it was a great name.

Here's the original arrangement.  It worked fine except for one problem.  The Sat Compass is all the way aft.  It's got a good clear view of the sky which is good.  The various devices are show in the picture.

Original stinger arrangement

 The problem is that it hangs out near the exhaust stack, and when there is a tail wind the soot and heat gets blown up towards the compass.  In the picture below you can see the sooting on the underside.  We had a couple of times when the compass locked up on us, and both times we had a strong tail wind and there was a lot of soot.  The theory was that the device was overheating, so I wanted to get it away from the exhaust.

Sooting suggests we are too close to the exhaust stack.
In the new arrangement the sat compass has been moved forward.  It's equally clear of obstructions, and now well away from the exhaust.  The secondary GPS and weather sensor are on the two side "horns".  I eliminated the XM weather.  The lightening brush still needs to be reinstalled, and it will go aft since it doesn't care about heat from the exhaust.

New stinger arrangement

Doing this was actually a royal pain in the ass.  The N2K cables for each device thread through the stinger and down the stack.  And they only come out through the top, so two of the three had to be pulled all the way out, then snaked back through, and down the stack.  This also included removing the connectors at the lower end, then reinstalling them after re-routing.  But now it's done.  One more thing off the list.

Thursday, March 5, 2015

Engine control and radar display

Progress is being made.  Back in this posting I talked about some of the control panel layout changes that I have planned.  Some of them have now come together.

Original main engine control panel and radar "pin-up" where the wing engine control panel lived

The first project was to transform the combined control panel that I created with photoshop into something real.  Here it is complete and installed.  I had to reset the configuration on each display so they would realize that all the individual gauges are gone, but after that was done everything worked great.

New combined engine control panel for wing and main engines

With the space freed up by the wing engine control panel, there is now room for the 1835 radar display.  This is a stand-alone 4kw radar that will serve as back up, and for use while at anchor to conserve power over the big 12kw radar.

Furuno 1835 radar display where old wing engine panel used to live.

Here's a good overview of the upper helm panel with the new components in situ.

Radar and new engine controls together in one place