Autopilots, Salinity, and Gizmology

There is something refreshing about a deadline that looms with implacable insistence. Instead of the casual plasticity of self-imposed schedules, there arises an urgency tied to the plane tickets of house sitters and the contractual inflexibility of marina move-out dates.

Given all that, we have recently noticed a increase in the completion percentage of the lists (clearly defined tasks, purchases, project management documents, general to-do, and so on). It is difficult to detect whether this is attributable to an actual increase in productivity or is just a growing reluctance to add new tasks, but really... who cares? The important thing now is more evenings like the one the other night with friends on Baccara and My Decade, as well as maximizing Time On Water even if the adventures are thinly disguised as autopilot commissioning, salinity-vs-power tests on the Sanitation Device from Hell, or a succession of pragmatic missions (Brion blessing the Hood in-mast furler, Andrew installing the Little Cod woodstove, prostrating ourselves before marine plumbers in the vain hope we might petition for a moment of their time, or even, dare I say it, learning the boat and just plain sailing).

What this translates into, from a bloggish perspective, is a backlog of news.

Tina the Autopilot

(Tina Turner, of course)

One of the big jobs that I've known about since before buying the boat is autopilot replacement... the clunky old Robertson not only suffers from a mysterious internal confusion regarding compass heading but was also associated with an industrial-scale continuous-running hydraulic pumpset that would drive us mad while killing the batteries. "Replace autopilot" was thus one of the first items on the to-do list, a classic illustration of the inverse relationship between the number of words required to express a task and the number of hours required to complete it (the Roberts Law of Creeping To-Do List Complexity).


Given the monstrous 30 cubic inch Wagner N50-300 hydraulic cylinder that drives the rudder and the desire to have the new contraption play nice with N2K lingua franca, it didn't take long to winnow down the available choices. I selected the Simrad AP24 (some on eBay over here).

There are a lot of pieces to an autopilot system. A computer is at the heart, of course, with a separate display head providing a user interface. It needs to know the ship's compass heading, rudder position feedback, and course data if proceeding to a waypoint rather than just maintaining a fixed direction. A remote control is essential, making it possible to drive the boat without being tied to the helm, and the "business end" is a motorized unit that powers the rudder back and forth without fighting other steering inputs (in my case, the wheel). And, given a navigation network that makes every data source available, a clever autopilot can also incorporate wind data to replicate classic wind-vane steering (great for the trades) or depth countour tracking along bathymetric features. It will even auto-tack and fine-tune itself to the apparent wind, adjust its servo gain to sea state, and so on.

What this all translates into on Nomadness is a lot of mounting and connecting, which of course immediately introduces interesting challenges (since nothing, on a boat, is ever quite as simple as it seems). The old pumpset used heavy copper hydraulic tubing instead of the more modern flexible stuff, I was unwilling to start cutting holes in the lower helm for the control head while the availability of Furuno's long-promised NavNet 3D chartplotters is still a matter of considerable public speculation, running long heavy power cables through the innards of a boat is hard, and pieces of the old pilot had to get out of the way.


Since I wasn't quite willing to rip out the Robertson and leave a gaping hole to be filled someday by the back-ordered MFD8, I kluged a couple of felt-covered wood panels above the existing lower helm... and there installed the sexy Maretron DSM250 instrument display, an old GPS, the autopilot head, Kestrel 4000 weather instrument, Icom M72 handheld VHF, Zoom H2 audio recorder, and timer (with the little stuff all on velcro for quick removal). This is how it begins.

Terry from Anacortes Marine Electronics came over and did the hard hydraulic stuff, then once all the cables were run it was time to start testing. Basically, it came up pretty well, though we haven't had a sea trial yet and the rate gyro compass still needs to be swung (calibrated to the boat's considerable magnetic field). The Simrad user interface is a little ungraceful in places and it switches to Spanish if you hit the MENU key during rudder calibration, but still... I think it's going to be very cool. One of the best parts is the WR20 remote, which is a hand-held device (with neck strap) that talks to a networked base unit via Bluetooth and allows full control over ship steering (as well as some clunky ability to view data pages from other systems). I can walk around the marina with this and still steer Nomadness and observe her coordinates... which is kind of a strange thought. I always did love remote-control toys.

Blame the Salinity

As you may know from recent posts, one of the more annoying issues has been the plumbing... we really want to be free to wander around without having to tiptoe when it comes to discharge. The pieces are all in place and appear to be very well done, but the LectraSan - a gadget that seems to inspire love-hate relationships with voyagers - is not cooperating.

The symptom is a green-yellow blinky pattern that is reported to be due to inadequate current through the cabling, low battery, failing plates, or insufficient salinity. Since the plates seemed to be the only plausible cause, I gave it the muriatic acid treatment and was rewarded with a red LED and immediate shutdown, which means blown fuse or intermittent. More fiddling whilst lying in awkward positions, and then it was back to yellow-green. Raritan was not too helpful, reassuring me that "the unit is in the extended cycle and is treating properly" even though their manual says not to use it when this happens since it eats plates, and then, when pressed, advising me to pull out the poop-encrusted contraption and ship it to Florida or New Jersey. While that is quite an interesting toss-up, I am more tempted to use it as an artificial reef.

But a friend at the marina pointed out that the salinity of the mighty Swinomish should not be taken for granted, and that his LectraSan, in fact, is now including the identical failure mode in its repertoire of misbehaviors. A bit of research turned up the fact that the salinity in the open ocean is 35 PSU (Practical Salinity Units), or 35,000 parts per million of salt... while the Swinomish Channel, running back and forth between two shallow bays with much river outflow, ranges from 20-27 PSU at the north end down to 0-15 PSU south of La Conner, depending on phase of the moon and Skagit River discharge. The temporal salinity gradient might thus be keeping LectraSan current flow depressed (about 29 amps last night), triggering the error condition... so now we have yet another reason to flee this place of annoying cross currents and recently booted live-aboards for the timeless allure of open water.

Nobody ever said this was going to be simple!

I was going to wrap this up with a rhapsody on gizmology, one of the driving forces behind my chronic technomadness, but it's time instead to go do some. And besides, the geeky bits sometimes seem to pale in the presence of the more pressing issues... having the magic carpet complete enough to spirit us away on a moment's notice. I just got the ship's FCC licenses (SSB and MMSI, plus Radiotelephone), the hard mattress in the aft stateroom now has a latex layer, and the pile of boxed products is now noticeably reduced as their contents have become integrated into the ship.

Oh, and a quick footnote, speaking of geekery: I've been unable to get automatic RSS working here, since apparently Blogger only does it for Blogspot-hosted sites. I'm unwilling to manually edit XML each time, so I munged the Feedburner files (I think) to just point to the front page. If you know how to fix that so the RSS/Atom/whatever happens automatically, please let me know.

Cheers from the not-so-salty sea,
Steve

Working Aboard

One of the big startup challenges in the transition to a Nomadness-centric lifestyle is amassing a useful on-board workshop. This is not at all easy, and involves a fairly extensive suite of tools as well as hundreds of little 3-mil zip bags of small parts.

I quickly found that just skimming the good stuff from my lab is not the right solution; I can't really afford to break the home-base capabilities, and the on-board requirements are on a different scale. Take the vise, for example. At home I have a big Wilton that can hang on to most anything (thanks, Mark!), but that would be overkill for the boat. So there is a bag of clamping goodies, with a Stanley Multi-Angle Vise as the centerpiece:


This very handy gadget fits nicely in the companionway, can be fixed at any angle, and even has removable pads for the jaws.

But what about the huge pile of hand tools? I've tried the big fabric bag, which was awful, and also a large box, which was unmanageable. What ended up happening is a dedicated drawer with beefed-up bottom and stiffened latch, filled with roll-ups and other small packs by category:


The three gray Ergodyne 5870 rolls are general tools, wiring stuff, and "wrenchy" stuff; the yellow one is all drilling/cutting. The big black one is bulky stuff, the Raymarine pouch is measurement, the blue box under that is the sexy Link Tools socket set, and the green one in the foreground is the Brady IDPAL labelmaker.

There's more, of course (electric drill, goo, tape, test instruments, fabric and sail repair kit, and so on), but that's enough for now. I'm on the boat at the moment, winding down after a day of mounting instruments and attaching connectors. The rudder-angle sensor is sending data through the N2K network to the Maretron display and Simrad bluetooth remote, GPS and compass work fine, and I've just extracted an ancient CRT fishfinder that was taking up space in the future comm bay. More soon!

Fair winds (whatever those are... I think this thing is designed to sail),
Steve

Plumbing, the Depths

With departure from the marina looming rapidly, certain things have been burbling to the top of the to-do list... one of which is having a legal and functional sewage system. The ship came equipped with both Type I and Type III marine sanitation devices; the former a treatment system that discharges sterilized waste, and the latter a holding tank for use in No Discharge Zones.

The trouble is, the tank had apparently never been used, and the treatment system (a vintage LectraSan) was blinking its unhappy yellow "extended cycle" LED... meaning, presumably, that something was amiss. Coupled with four unlabeled Y-valves and a lack of documentation, we decided to convert the forward head to a dead-simple system: direct pipe to a new tank that could be either deck-pumped or macerated overboard when over 3 miles offshore. The aft head would be moved to the TBDWL category (To Be Dealt With Later), possibly to be the site of a composting experiment after this short sailing season gives way again to the cold short days of the Pacific Northwet.

All the new parts arrived at the plumber's shop, but he just took off for Europe and we are nearing a departure deadline. So last night we made a much more serious attempt to reverse-engineer what is already aboard, and discovered in the process that many of the initial assumptions were incorrect:


This will of course be redrawn somewhat more professionally, but I thought you would find amusement in the tangle of real-time notes (reflecting as they do the equally obfuscated reality). This information was extracted from the boat through many hours of crawling into impossible spaces, gripping flashlights in teeth, reaching deep into nests of umbilici and shooting blindly with the digital camera, tapping and tugging on hoses while the other person listens with stethoscope, cycling Y-valves and thru-hulls then seeing what happens, peering overboard while flushing, and no small amount of head-scratching.

What it reveals is kind of entertaining, and although the tank is small and the LectraSan still blinking yellow, it might get us through the season with a bit of maintenance work. Basically there's a valve under the V-berth that determines whether the forward pump draws from the head or the tank, another under the settee that pipes the result of that overboard or to the LectraSan, a third near the aft head that steers its effluent likewise, and a great loop-closing fourth that directs the treated waste either out to the sea or into the holding tank. The latter is widely regarded as pointless, since it will not stay sterile, but it's an interesting work-around for No Discharge Zones.

I guess the good news is that it is now much less mysterious, which means we have a fair chance of using it as it is (at least during the upcoming shakedown cruise). Some photos from last night:

Hmmm, I wonder where this one goes...

The small 20-gallon tank is behind the deep freezer, and opening the space reveals the area where the new communications console will be installed...
The LectraSan with its output selector valve and an unrelated thru-hull...

Ah, the joys of messing about in boats!

Footnote Jun 27 (while trying to fix a persistent atom/rss bug that apparently has my feed frozen in 2006... apparently site feeds do not work with private or FTP-hosted blogs, which this is): The LectraSan is not cooperating, and I'm starting to see why there is such a love/hate relationship with them among cruisers. At the moment, my emotion is not a warm one... about the sewage OR the feed.

-Steve

Renaming

We haven't done the renaming ceremony yet, but the lettering is in progress and looking good! The starboard side is done; next warm day we'll ease her across to the next dock and do the port...


We ordered the letters online at Speedy Signs, and so far it has gone well (though it takes patience and careful attention to detail).

Today saw a bit more cabling (N2K to the comm bay), additional system design, and much head-scratching about the mounting of the Icom AT-140 antenna tuner to allow a short run to the backstay as well as a direct path to ground (via a big high-voltage mica capacitor). So many projects, so little time.

Meanwhile, our plumber over-committed and is now off on a 3-week vacation just as the holding tank is arriving, so we're on an emergency quest for someone to help with that project in the 3 weeks remaining before we leave the marina. Nothing on a boat ever goes quite according to plan!

Cheers,
Steve

We Have Backbone!

The boat is now awash in tools, gray NMEA 2000 cables, little clusters of parts, removed panels, and the general unnameable clutter of any large project. A few days ago, I ran the backbone of the network using all Maretron hardware... centered both electrically and conceptually at the inside helm station:


The yellow connector is the power tap, which introduces 12 volts to the network via a dedicated circuit breaker. On either side of that are 4-port tees for the local devices, and from each end go the lines to other regions of the boat... out the top sternward to the autopilot and aft helm gear; out the bottom to the wind/depth instruments and the comm bay. (Here is the current network drawing in PDF form.)

It is well-known that cabling on a boat is hard work, but we thought we had seen the worst of it after using a conveniently embedded string to pull the 7-meter run between the hydraulics cabinet at the stern and the power bays in the pilothouse. I plugged in the Maretron GPS and rate gyro compass, hacked a proper N2K connector onto the proprietary Simnet cable associated with the Bluetooth autopilot remote, and was able to see live data while strolling wirelessly about. Safari, so goody.

I paused to research the ideal mounting location of the compass; being a steel boat, Nomadness will inevitably distort the earth's magnetic field, and folks have traditionally gone to great lengths to put their heading sensors as far from ferrous influences as possible... like partway up the mast. This is a questionable idea due to the huge increase in roll/pitch/yaw acceleration noise as the boat dances through the waves, and it's also hard. I had thus more or less resigned myself to a custom enclosure on the radar arch, when Maretron responded to my question in detail and reassured me that, based on their experience with a hundred or so steel boats, the problem is not that serious with rate gyro technology (unlike old flux gates, which also really like to be level). This happy news opened up the nav instrument pod over the companionway as an option, also a perfect place for the GPS and the wireless base for the autopilot remote. And it's easier too, surely.

Soooo... figuring it would be a quick run of about 4 meters worth of cable followed by much fun involving the shiny new DSM250, we started probing for openings early Wednesday afternoon. But my cable tracer revealed signals wandering off in an unexpected direction, so bits of the boat started getting removed... and by nightfall we had the headliner off and were beginning to disassemble the shower compartment. Sure enough, with plenty of tight bends, there was a convoluted path... and it was packed with wire.

While trying to figure out how to poke a soft cable through it without the assistance of a highly trained cockroach trailing a string, we discovered something unsettling: a seriously melted wire pair bound into a major harness, heading out of the DC power panel area. Not good... this happened on BEHEMOTH one smoky night in the bikelab due to a big grounding oops, and resulted in redoing most of the cable harness. I gingerly began separating the largely bare and corroded wire from its neighbors, sometimes pulling away fused insulation, and finally isolated it to the starboard windshield wiper.

Issues with wipers aside, this opened up a wonderful opportunity... use the trashed cable to pull the new N2K one! It was still a battle, but by about 2 AM we had it dangling happily next to the network tees and started screwing the boat back together.

And then... darkness. I had just driven a wood screw through the cable to the overhead galley LED light, and popped the circuit breaker. ARGGGHHH. I'll deal with it in the morning.

Skyak and Nessie

In other news, we finally got out on the water in our kayaks... it has been such a relentlessly cold year (even now, in Junuary), that paddling hasn't been all that alluring. As I mentioned in an earlier post, mine is the pedal-powered i12S inflatable from Hobie, and Sky's is the new Expedition from Advanced Elements. It tracks beautifully, and seems to suit her well:


Unlike mine, it packs into a sane and manageable package, especially with a Hobie 4-piece paddle. (I have no idea where Nessie is going to stow aboard... probably loosely inflated and lashed to the lifelines). I still prefer the pedal drive and over-the-top galumphing geekiness of mine, but if you need an affordable inflatable kayak that tucks away neatly, this is surprisingly good stuff (click to go to REI):




Adventure Plans

The sudden surge of activity is no accident; we're leaving the marina very soon and going on the hook prior to actually amortizing this ship rather than treating it as an endless collection of projects and gear-buying opportunities. The next 3 weeks should see the installation of a new holding tank and corresponding plumbing, integration of the autopilot, and at least a temporary loaner chartplotter since Furuno was over-optimistic about taking orders for their sexy new Navnet 3D and the back-orders are becoming stuff of legend.

This blog will continue to be the primary venue for updates, though one of these days I really need to replace the Nomadness root directory with Joomla. I'm developing quite a backlog of technical material that would overload the blog format and be impossible to navigate. Quick ephemeral notes, like current eBay activity, continue to post more-or-less weekly on my live page.

Cheers from the water... well, sorta almost,
Steve

Hanging the Dink

Quick update before I plunge back into N2K goodness this week... the 10' Navigator dinghy is now securely hanging from the davits. It's a simple procedure, now that it's essentially done: attach bridles to the bulkhead fixtures in the dink, remove the starboard dinghy dog flotation collar, use the 3-part-purchase tackle assemblies to hoist the boat all the way up, make fast the lines on horn cleats (though still with the Hitchcraft widgets until I get the cleats mounted to the radar arch), use boat hook to catch the black nylon webbing straps and pull them under the hull, cinch those up in the stainless ratchets, open the drain to let out the rain, and tidy up. Here's what it looks like:


I may add a couple of rigid pads where the davits take that unnerving bend (which may someday need a gusset to avoid bending further), just to give something solid to pull against... but the mounting is surprisingly stiff. Finding stainless ratchet strap assemblies was a key, and I was delighted to discover these on eBay (click "view all" to see his other sizes and strap-end options):



Pieces are coming together. A lot has to happen over the next few weeks... if we don't get moving, our housesitter is going to get very annoyed with us! <grin>

Cheers,
Steve

NMEA 2000 - The Journey Begins

I have mixed feelings about this, but there's really no choice. The old marine "networking" standard (NMEA 0183) was little more than glorified 4800 baud serial datacomm, with various vendors producing their own variants to jockey for competitive advantage. That's not very interoperable.

NMEA 2000, the new stuff, is based on the well-established industrial CAN (Controller Area Network), and is technically far superior to the vintage 0183 protocol. There can be lots of talkers, it's faster, it's electrically robust, it carries power to all but the thirstiest loads, and it can even be hot-plugged. All the latest marine equipment is designed to work with this, though some vendors still insist on forcing people to buy their own connectors and cables (going so far as to give their flavor of the standard a distinctive name to discourage shopping around). This is annoying, but easy to fix once you know the game.

What is more frustrating is that it is not really an open standard (as are the various layers that make up the Internet), so the cost of entry is high and there are substantial legal disincentives to hack, reverse engineer, productize, or even publish without paying to be in the club. This discourages hobbyists, and even those who do come up with something clever at the network level are prevented from going public. For an old geek like me, this seems self-serving in a very destructive sense, but there's enough momentum in the industry that it will stick anyway. Besides, as I said, it really is good stuff, and there is much to be said for standardization and interoperability without a long shake-out period (remember S-100?)

So with all that out of the way, and recognizing the handwriting on the wall, it is time to move forward with the ship systems. One of my best educational resources for N2K and marine electronics in general has been Panbo; another is the network design guide published by Jack Rabbit Marine.

I'm basically thinking of this in two major zones. The first is off-the-shelf NMEA 2000 equipment (hereinafter called N2K) that is interconnected by a Maretron backbone, and available to the server via a USB interface. Scattered around the ship are sensors, instrument displays, chartplotters, an autopilot, engine interface, and even a two-layer gateway that lets the ancient B&G network sensors get translated to NMEA 0183 and thence to N2K. The Simrad autopilot uses "Simnet," which is really N2K, so interfacing that is just a matter of wire cutters and field-attachable connectors.

The second zone is my own stuff... also hanging off USB, but taking the form of direct I/O and other interfaces to incorporate system configuration tools, power management, security, and a variety of environmental sensors. The server (probably a Mac Mini, since I gave up on Damn Small Linux... though maybe an embedded ITX or Asus if power considerations overcome the hassles of KVM switching) will then turn all this into a database-backed website, accessible on or off the boat.

But that fancy tinkering is for later. The immediate project, now underway, is getting the essential navigation tools all playing nice on the network: two Furuno NavNet 3D multifunction displays, the wind/speed/depth sensors, GPS and compass, autopilot and its wireless remote, rudder angle sensor, instrument displays, engine and fuel consumption data, tank levels, and so on. Here's how it all fits together (revised Jun 19, 2008):


The blue sections are physical regions of the boat, and they are linked by the N2K network. Because there are alternatives to the simple "tee" in the form of 4-port tees and multiport boxes at the end of drop cables, I have tried to minimize the cabling (and cost) by grouping things as efficiently as possible. And the terminating resistor at the mast step, which seems like a strange place to end the backbone since the Comm Console is not so far away, is to set myself up for the future transition from legacy masthead instruments to their N2K counterparts... with the network termination moving 60 feet up in the sky.

The bulk of the activity is behind the nav and power consoles in the pilothouse, where all the lower helm controls, engine and tank monitoring, and circuit breakers are located. This is also the location of the autopilot control box, which communicates over the network with the pilot itself back in the hydraulics bay. Further down the line, at the binnacle (the outside helm), there is a base station for a wireless autopilot control... putting the Bluetooth RF link entirely outside the steel hull. This is the sort of thing that highlights the value of the N2K network - not only does it let sensors talk to instruments, but it eliminates (in many cases) the need to run a bunch of parallel cables. The exception is the red line... ethernet between the Furuno multifunction displays that also handle IP video, chart downloads, and other bandwidth-intensive stuff (note that only one of the Furuno rigs can be connected to the N2K backbone; the high-speed network between them carries the data and also supports power synchronization).

(Incidentally, the ethernet LAN will probably be slightly confusing at some point, as one of those plotters wants to play DHCP server. I already have DHCP in the form of the boat's wireless router with upstream EVDO, so I guess those will end up on separate IP spaces. Not sure how all that will shake out when/if I want to start playing with more interesting applications at the Mac end.)

Anyway, current status on the hardware side of all this is that the network wiring is on board and I'm starting to run cable. The boxes themselves are piling up, awaiting installation.

Hanging the Dink

In other news, the 10' Navigator dinghy is now lightly dangling from the stern davits, and I'm awaiting the stainless ratchet straps that will let it be attached snugly enough to withstand a bit of bouncing (just a bit; offshore it will be lashed on the foredeck). I only mention this to give a well-deserved plug to the Hitchcraft RopeTie - one of those "why didn't I think of that?" gadgets that is now always in my rigging kit. These come in two sizes, and let you create a stable tie under tension (like a trucker's hitch, but much easier). Here's one of mine, temporarily holding up the stern of the dinghy until I manage to get horn cleats screwed to the underside of the radar arch:



There's a lifting bridle at each bulkhead of the dink, hanging from the davits... I fabricated these with Nicopress terminals and jacketed stainless cable, as well as Ronstan blocks and carabiners:



So, there is tangible progress on a couple of fronts... and the plumbing hardware is now on order. Sky's kayak (Skyak, of course) arrived today, and there seems to be hope for sunshine sometime soon. Time on water? Could it be true?

Cheers,
Steve