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Sunday, June 23, 2013

Building the Navigation Computer

Back in my discussions about chart plotters and other navigation equipment, you may recall that I've picked Rose Point Marine's Coastal Explorer as my primary charting software.  One of my side projects has been to sort out the computer that I'll use to run Coastal Explored (CE) along with a few other navigation related programs.  I'll have two computers in the pilot house, one dedicated to critical navigation tasks and locked down so random software isn't being installed, and with tightly controlled network access, all geared towards keeping the system reliable.  The second computer will be more casually controlled and be used for email, web browsing, music and videos, etc.  The goal is to have common hardware so if I need to cannibalize the casual system to repair the navigation computer, I can easily do that.

I'm a total convert to Macs.  I've suffered through every version of Windows since V1.0, and did so because there have always been a handful of apps that were only available on Windows.  All it took was one app to keep you from a Mac.  But all that changed with the advent of VMware Fusion and Parallels.  These programs let you boot and run windows as part of MacOS.  You can run Mac and Windows apps side by side.  This had broken the Windows stranglehold and allowed me to dump my PCs and never turn back.  Now I suffer though Windows only for the few apps that are still only run there.

OK, I'm done with the rant, but the bad news is that CE is one of those apps that only runs on Windows.  This unfortunate reality means that I either need a PC for the nav system, or a Mac running either Fusion of Parallels.  Since I prefer a Mac in every way, it's an easy decision, so I started putting together a Mac Mini.  It's a nice compact machine, has very low power draw, supports dual screens, etc.

There's another reason too.  Since the introduction of the iPhone, scrolling on handheld devices has been the reverse of a computer.  On a computer, the scrolling action moves the window over the document; scrolling down moves you towards the bottom of the document.  On a touch device you drag the document within the window; dragging down takes you towards the top of the document.  About a year ago, Apple changed the scrolling in MacOS to match the touch devices.  It was very disorienting at first, but seems completely natural now - at least until you get on a PC - then everything is backwards again.  One of the things I struggled with on the MaxSea laptop was the scrolling.  I'd scroll one way to zoom in or out, and it would go in the opposite direction from what I expected.  Add to that the redraw delay and I never knew if I was coming or going.  All this is a long way of saying that when you run a windows app via Fusion on a Mac, the scrolling on the windows app is consistent with the Mac scrolling, not the opposite, so everything works as expected.

The big remaining question has been how CE would run under Fusion or Parallels.  They both extract a performance penalty on the underlying windows app, and I wanted to be sure CE would be responsive, especially for scrolling and zooming charts.  Another concern was how well the various USB interface devices would work.  I've got three of them for this computer.  They are:

1) Rose Point's NMEA 2000 to USB converter.  This allows native N2K communications between CE and the rest of the boat.  There is no translating back and forth to NMEA 0183, and no resulting loss of information.  Since I started this project Rose Point really fleshed out their support for N2K, bringing it from a rudimentary implementation to a very complete one with all the requisite features for use on a larger boat with a more complex system.  I participated in the Beta program for this feature and have been using it on the Grand Banks since launching this spring, and it's working great.  This was one of the leaps of faith that I took with this whole nav system, and Rose Point didn't let me down.  Back to this particular interface, I picked the Rose Point device because there will be no excuses from Rose Point for it not working.

2) Maretron USB100 NMEA 2000 to USB converter.  I've had this device for a few years and historically use it to run Maretron's N2K utility program which is very handy for confirming proper operation of your N2K network and devices.  It also works with CE, but Rose Point says they cannot guarantee bug free operation because Maretron has stopped supporting third-party use of the interface.  This is what drove me to get the Rose Point Interface, but I continue to use the USB100 for the Maretron diagnostics program.

It's not only important that these devices work, but they also need to work properly through sleep/wake cycles, and shutdown/reboot cycles on the Mac.  Plus, they need to work through start/stop of Fusion, boot/shutdown of windows within Fusion, and suspend/resume of windows within Fusion.  In my experience, this sort of thing has always been problematic under Windows.  Layer in Fusion and MacOS and the risk only goes up.

I've never tried Parallels, but have been running Fusion for about 4 years now, so that seemed like the obvious starting point.  I've heard good things about Parallels and suspect it would work just as well as Fusion, but I've got enough new stuff to learn so I started with Fusion.

So, with the mini set up, Fusion installed, and CE installed, it was off to the races.

Fast forwarding ahead, the results are excellent.  CE's performance is more than acceptable.  The Apple wireless mouse and keyboard are small and comfortable to use, and the mini's form factor and low power use are well suited to a boat.

After getting everything working, I decided to do a few things to help ensure success.  The Mini that I bought was the lowest end model.  I figured if it ended up being too slow for CE, I could always move it over to be the second computer on the boat and get a faster one for the nav computer.  But performance wise it was fine so I decided to stick with it as the core computer.  However, I was running at the minimum recommended memory size, and I'm a bit worried about disk activity slowing things down when CE needs to fetch charts from the disk.  So I decided to pimp the machine out with max memory (16GB) and a solid state disk (SSD).  In addition to being faster, the SSD also draws less power than a spinning disk, and is immune to physical jostling around which happens on a boat.  I think this is a really good application for one.  Swapping memory on the Mini is a piece of cake, and 16GB only cost  $110.  Swapping the disk was a bit trickier, but with patience and the right size Torx drivers it's very doable.  I went with a 256G drive which is more than enough for this application, and it only set me back $190.  Now I have a smokin' fast, physically robust machine that runs CE like a champ.

But nothing is perfect, and I did discovered a few nits along the way.  The Mini can be powered down from the keyboard, but it can't be powered up.  You need to press the power button on the unit itself.  That's not conducive to mounting the computer in an out of the way cavity on the boat.  The last time I used a Mac desktop was back in the 90's, and at that time you could power it on from the keyboard.  I assumed that was still the case, but the salesman looked at me cross-eyed when I asked what had happened to that feature.  I haven't looked around yet, but it might be possible to have the Mini automatically boot when power is applied.  If so, I'll set it up that way, and I should be able to trigger a boot by cycling the power breaker.  The other issue is the SD card slot.  That's the means to move data between the Mini and the Simrad equipment, so it creates another need for easy physical access.  If the power button and SD card slot were on the front side of the Mini it wouldn't be so bad.  I could put them in a cabinet and have all the wires neatly dressed in the back, and the computer front with power button and SD card facing out.  But both the power button and SD slot are on the back side with all the wires, so access will be ugly and messing with SD cards and power buttons in close proximity to control cables is likely to result in dislodged cables and unreliable operation.  If I can solve the power-on problem, then I might get a panel mount SD reader that connects to one of the mini's USB ports.  That combination should allow for mounting the mini where it only needs to be accessed for service.

Another thing I need to sort out is backup of both computers and a procedure for quick fail over or replacement if the Nav computer dies.  This will be a project for another day once I have the second computer configured and working.

Saturday, June 22, 2013

Nordhavn Rendezvous in Mystic

Last week Nordhavn hosted a rendezvous in Mystic, CT, so we used that as an excuse for our first boat trip of the year.  Despite having spent time in New England all my life, and living here full time for the past 30 years, I have to confess that I have never set foot on Martha's Vineyard or Nantucket, so we decided to change that as part of this trip.  Another first is that our son John decided to come along for the trip down to Mystic.  Our kids have been out of the boat many times for day trips, but never for a cruise, so it was great to have him aboard.

Day one we made a marathon run from Gloucester, down through the Cape Cod Canal, out through Woods Hole, and over to Vineyard Haven on Martha's Vineyard.  The whole trip was pretty calm except the last stretch from Woods Hole to Vineyard Haven where the wind and chop kicked up.  We somewhat randomly picked the Black Dog Wharf as our tie up point, and it was just that - a fixed wharf.  No problem, and we got in and tied up, but pretty quickly discovered that we were getting knocked around badly by a side swell that was coming in.  After toughing it out a bit, the rolling was so bad that our upper deck was hitting the pilings so we asked about moving to another location where we would be bow to the swell.  With a little performance of the untie and retie dance, the problem was solved.

Then I got to start fixing all the little things that had not quite survived winter storage.  There are always things that need to be fixed on a boat, but sometimes it seems more overwhelming than others.  On our way over, one of the sinks was draining slowly.  Then the other sink backed up completely, and there was water coming up out of the shower drain.  I guess the good news is that it was the sinks and shower, not the toilet ;-).  Except for the kitchen sink,  sinks and showers drain into one of two sumps where it is pumped overboard.  I had tested both sumps when I commissioned the boat this spring and they were working fine.  In the past, the float switches have gotten gunked up and the sump would not shut off, so I've taken to checking them.  After a bunch of messing around with the relays and wiring, I was able to hot wire the switch to run the pump long enough to get it drained down so I could open the sump without all the backed up water dumping into the bilge.  After opening the sump and screwing up the courage to start fishing around in there, I once again found a gunked up float switch, but this time it wouldn't turn on where last time it wouldn't turn off.  After a good cleaning, everything was back to normal.  From now on I'll make a point of thoroughly cleaning both sumps before putting the boat away for the winter.

The next problem was discovered on an engine room check on our way down.  I spotted some oil in the catch pan under one of the engines and traced it to the hydraulic oil filter which was wet around the seal.  I also noticed almost 30 PSI of pressure on the return line which struck me as quite high, and I immediately assumed that was the cause of the leakage.  A check with the outstanding techs at ABT revealed the return pressure to be normal, and once the engine room was cooled down I found nothing more than a loose oil filter.  After over 40 years of changing filters, this is the first time I've had one come loose on me, but I guess there is a first for everything. So I tightened it up, cleaned up the oil, and we are back in business.

The good news is that the coolant drip and the two oil drips that I fixed over the winter appear to be solved.  And the water that would appear around one of the stabilizers every time we were in rough water is now totally gone.  It was just a bad joint on the bilge pump hose, and in rough water some water would flow backup through the thruhull and leak out of the joint.  Of course I thought the worst and feared the leak was the stabilizer itself, but it's dry as a bone just as it should be.

We hung out for two nights and got a chance to walk around Vineyard Haven, sample the food, and pickup a few trinkets.

Wednesday we headed out to Mystic which was another 70nm run, but this part of the trip really sucked.  We had 25-35kt winds on our nose the whole trip and it was a very wet and rough trip.  Around Newport and Pt Judith the windshield was covered with water more than not.  During this submarine ride, we also discovered a couple of portholes that weren't quite dogged down tight enough and we ended up with water in a few places, including a pretty wet mattress.  We now have a more rigorous check process once we get underway, and especially when we encounter weather.

After getting knocked around for 6 hours, Long Island Sound was a welcome settling, and things totally flattened out in the Mystic River.  The rendezvous was being held at the Mystic Seaport Museum where there are a number of sea walls and docks that very deftly accommodated all the participants.  ANd teh coolest part is that you are docked inside the facility grounds adn have free run of the place, even after hours when the crowds have left.  I highly recommend it as a stopping point.  Getting to the Seaport Museum requires passing through two lift bridges, one of which only opens at 40 minutes after the hour, and only if you are there to tell them you want an opening.  We managed time time it pretty well for the 3:40 opening and found ourselves clustered with 3 other boats (all Nordhavns) waiting for the opening.  Once through the bridges and tied up, we were able to get the salt washed off the boat and settle in for several days.  John needed to get back to Boston so we sorted out the train schedules and closest station with regular service (Westerly, RI) and off he went in a cab.

The next several days were packed with seminars, putting names and faces to people you only know via email, and getting to know other owners.  And as a side note, I should remind everyone that our Nordhavn is still in the ship yard in China, so our job was to pollute the Nordhavn gene pool with our Grand Banks.  We were the only non-Nordhavn there.  But it's a great bunch of people, and we are greatly relieved by that.  As you get into bigger and bigger boats, the egos get bigger and bigger.  I had just finished reading a book about the building of a mega yacht which by all indications is an industry that is all about egos, all the time, and we were a little worried that we'd start encountering that with the Nordhavns.  But I'm glad to report that reality couldn't be different.  These boats are made to be cruised, and with few exceptions, cruised by a couple.  This really comes through when you meet owners who uniformly love cruising, and have left behind the baggage of the successful careers that put them in a nice boat cruising the world.  We also had dinner one evening with Dan Streech, President of PAE (makers of Nordhavns), and he's just as down to earth and unassuming as his partners and all the employees at PAE.  I think we've found a new extended family.

On our trip back we stopped at Cuttyhunk for the night figuring we'd get our usual quiet evening on a mooring.  But it turns out the channel to the inner harbor is being dredged, and that they run 24x7.  We were on a mooring in the outer harbor and were far enough away to not be too bothered by it, but every few hours the dredge would motor by to go dump the tailings.  Not the usual Cuttyhunk experience, but not too bad either.

Both the ride to Cuttyhunk, and the following day back to Gloucester were like glass for all but the last 30 minutes or so where we got an afternoon squall just in time to soak us getting off the boat and back to the house.  And although there is still a list of things to do, the boat is in great shape and running well.

Monitors, more monitors

This is the topic that won't die, or it's going to kill me along the way.

When we last left off, I had picked a 19" Samsung desktop monitor to use on the boat.  Although it blurs and distorts the display image from my Simrad NSO, it was still deemed better than paying 20x to 30x the cost for a "marine" monitor.

Since then the decision has had time to simmer, and I moved the Samsung monitor to my Grand Banks to get some actual run time with it.  Two things have come from this simmering time:

1) If the Simrad only puts out a 1024x768 video signal, why am I trying to force it onto a 19" screen that insists on blurring and distorting the image?  Why not put it on a 15" screen that matches the Simrad resolution and will display a clear, sharp, undistorted image?  Duh?  And there is a side benefit.  By using 15" screens for the Simrads, it frees up enough space on my console to use 24" widescreens for the computers.  This gives clearer images, and allocates the screen space to the devices that can use it.  This makes much more sense.  I think I was hung up on all four monitors being the same size so the console layout is attractive, but I realize that the center of the console can have a 24" widescreen in the middle, flanked on both sides by 15" screens, then the second 24" on the right console "wing".  It will look fine.

2) Brightness really matters to me.  Part of this is just that I'm getting older and need things to be more brightly lit than I used to.  I remember as a kid when I'd be working on something, my father would always ask me if I needed more light.  Now I understand.  Monitor brightness is measured in NITs.  A desktop monitor goes to 250 NITs, where a sunlight readable screen is typically around 1000 NITs.  This really struck me using the Samsung on the boat next to the Furuno MFDs.  The Samsung's 250 NIT brightness was much harder to see than the Furuno's 1100 NIT brightness.  And this was at the lower helm, not out in full sunlight.  And the reality is that only the marine and other specialty monitors offer the higher brightness.

This last issue of brightness has caused me to seriously consider bellying up to the bar and forking over for marine monitors.  I never though I'd get there, but I know I'll be unhappy if I always feel like someone turned down the lights.

So I've started researching the marine monitors more closely, looking for a 15" monitor and a 24" widescreen monitor, preferably from the same company so they match.  I also started checking the brightness specs as well as other features like dim-to-black and DC power.  I figure if I'm going to pay a fortune, the monitors should be exactly right with no compromises.

15" monitors are not a problem.  Everyone seems to have one, but I did find that the brightness varies a lot.  Some companies have "Pilot House" versions of their monitors along with "daylight visible" and "sunlight visible".  Each has very different brightness specs.  And of course these different models come at different prices.  One of the more affordable 15" monitors that I was looking at turned into a $7000 monitor when I was specific about wanting the brightest model.

The 24" widescreen is more of a challenge.  None of the big-name navigation equipment vendors offer one, and not all of the specialty vendors offer one either.  And pricing still hovers in the $7000+ range for the larger monitor.

Back to Google, I searched and searched for any form of sunlight readable monitor and finally stumbled across a company that appears to actually manufacture them along with a wide range of hardened PCs for harsh environments.  They have a very impressive list of customers, have been around for 20 years, and based on the specs, dimensions, drawings, phones, etc., make the monitors that one of the larger specialty marine suppliers sells.  But unlike the specialty vendor, they offer a wider selection of sizes including the ones I want, and sell them for about 1/3 to 1/2 the price.  Bingo.  This might be it.  I won't name any names until I have vetted it out, but once I have a solution, I'll share all.

Link to next article on monitors

Tuesday, June 4, 2013

Monitors, damn monitors.

Shifting gears back to the Nordhavn, a while back I selected the Simrad NSO black box navigation system, but deferred on the selection of monitors.  Little did I realize what a time consuming and frustrating experience would be provided by the seemingly simple exercise of selecting monitors.

First, lets take a look at what I'm trying to accomplish.  I want four monitors, one for each of the two NSO processors, and one for each of the two computers.  And I want them as large as will fit.  Furthermore, I want all the monitors to be identical so I can interchange what's displayed where in case I change my mind about the arrangement of displayed information, and for backup/redundancy in case of failures.  All this rolls up to four 19" non-wide screen monitors.  Sounds simple, right?  If only it were....

The next major decision is whether to use "marine" monitors or standard commercial monitors.  The marine monitors have a few features that tailor them to the application, some of which I care about and some I don't.  The features and their relevance to me are:

  • Waterproof.  These four monitors are going in the pilot house, so there is no need for waterproof monitors.  I don't care at all about this.
  • DC-powered.  This has some attraction since it theoretically reduced power consumption by eliminating the inverter losses to run off AC.  Underway the engine generates plenty of power so this only matters when running the displays at anchor.  DC power brings a slight advantage, but it's not a deal breaker.
  • Designed for panel mounting.  The marine monitors are designed to be panel mounted and come with all the necessary hardware.  This is a slight advantage, but the boat yard is quite good at mounting standard monitors so this doesn't really matter.
  • Lots of different inputs.  Each monitor will be connected to exactly one device via DVI, so I don't care about this feature at all.
  • Dim-to-black control knob.  This offers convenience when dimming the monitors for night operation, and dimming all the way to black is handy.  But a button menu to dim is OK too if it's simple, and theatrical gels can be used over the screens to dim them more if needed.  So the dimmer knob is a slight convenience, but not a deal breaker.
So the marine monitors offer a few advantages, but none of them are deal breakers, so the question becomes "at what cost?"  And that's the real kicker.  The marine monitors cost between 30x and 60x the cost of a commercial monitor.  Yes, that's right.  A commercial monitor costs about $150, where a marine monitor costs anywhere from $4500 to $9000 each.  That $18,000 to $36,000 just for four monitors.  What would you do?  Probably the same thing as me - get the commercial monitors and live with the differences.  Then it's just a matter of picking which brand/model to use.

Backtracking a little, the NSO bundle that I bought included a 17" marine monitor, and using it I came across an interesting issue.  I'll apologize in advance for the deeper than usual tech dive.

All monitors contain a certain number of pixels arranged in a grid.  The computer lights each one up to draw whatever image is required.  Pixels are square so the computer knows how to properly draw circles, squares, etc.  Monitors all have a "native resolution" which is simply the number of pixels horizontally and vertically on the screen.  Normally the computer matches it's output to the monitors dimensions giving the clearest images.  But monitors can also handle smaller input dimensions and upscale the image to fit the screen.  You with me so far?  We are almost there.

When scaling an image, you need to consider it's aspect ratio.  An image that has 4:3 aspect ratio has 4 horizontal pixels for every 3 vertical pixels.  4:3 is the ratio for old-style TV. 16:9 is the ratio for wide screen TV.  All this matters because when you scale a graphics image.  You need to maintain the aspect ratio.  If you don't, the image distorts.  Squares are no longer square, and circles are no longer round.  On your TV you have probably seen "banding" at one time or another.  Those are black bands either above and below, or on either side of the image.  This happens when you scale an image to fit a screen that is a different aspect ration than the image itself.  You have probably also experienced the fat-ass syndrome where people on screen, especially towards the outer edges of the screen, seem to have particularly wide stances.  This happens when you do not preserve the original image's aspect ratio and instead stretch it to fill the screen and it's aspect ratio.  You can sort of get away with this for video, but it's a big no-no for graphics where squares need to be square and circles need to be round.

OK, with that tutorial out of the way, let's go back to the 17" marine monitor that came with the NSO.  The monitor has a resolution of 1280x1024 which is 5:4 aspect ratio.  It turns out, but the way, that 100% of the 17" and 19" non-widescreen monitors on the market are 1280x1024, 5:4 ratio.  The rub here is that the NSO outputs 1024x768 which is 4:3 ratio.  No problem, right?  The monitor should scale the input signal of 1024x768 to fit the monitors 1280x1024 pixel grid.  Maintaining aspect ratio, the image would scale to 1280x960, leaving a top and bottom black band on the screen.

Well, not with this monitor.  Instead it stretches the image to fit the full 1280x1024 screen thereby converting the aspect ratio from 4:3 to 5:4 and turning all the circles into ovals.  WTF?  Instead of range rings you have range ovals.  WTF? After a little back and forth with the manufacturer I concluded there was a reason why this "marine" monitor only cost $2000 where the others cost $4000.  And it turns out this was just the tip of the ice berg.

Having rejected expensive marine monitors because of their ridiculous cost, off I went to research commercial monitors.  I had a number of leads based on monitors used on other boats and web research.  I also had a clear preference for LED monitors.  LED back lighting, as opposed to florescent back lighting, tends to be brighter and lower power.  The first challenge was finding a non-wide screen monitor.  Nearly all monitors are now wide screen.  It appears that the convergence of computers and video has indeed taken place.  But most major vendors still have a 19" non-widescreen monitor.  My first two pics were an LG and a Viewsonic.  I bought both, figuring that I'd just return whichever one lost the comparison.

Long story short, both monitors, along with the original "marine"monitor and two more subsequently purchased ALL distort the NSO video signal when scaling it to display on the monitor.  Now a little more attuned to the issue, I rejected two or three additional manufacturers based on their manuals and/or tech support feedback.  That's seven manufacturers all of whom incorrectly scale input images.  At this point, I give up, and conclude that all the current LED monitors of this class improperly scale images.  So what's next?

A fellow Nordhavn owner much more skilled in google searching that me discovered a device by a company called Gefen that scales VGA input signals to match various DVI output signals.  It looked promising, so I bought one.  The good news is that it does indeed scale the input signal while maintaining aspect ratio.  But the bad news is that the video quality is poor.  Edge definition is fuzzy and the overall appearance lacks sharpness.

It seems I can live with one of two issues; distorted graphics shapes, or overall fuzzy images.  hummm?

And what about those expensive "marine" monitors?  Do they scale images properly?  Reading their manuals, it would appear some have an option to "maintain aspect ratio" so I think the answer is yes, but is it worth 30x the cost?  For me, the answer is No.  I just can't bring myself to pay such a "yacht" price for something, and I have a problem in principal rewarding any company with a purchase who has such business practices.  There are plenty of yachties with deep, wide open wallets, but I choose not to be one of them.  I'm happy to pay for value, but come on, 30x is ridiculous.

Are you dizzy yet?  Well, welcome to my world.  It seems ridiculous that this is so complicated, but it is.  That said, in fairness I have to admit that a big part of this is due to the Simrad NSO which is only able to output 1024x768 which does not match current monitor technology.  Furuno, and perhaps others, output 1280x1024 which happens to match the monitors and hence does not exhibit this problem.

The bottom line is that I have 3 choices:

  1. Live with the distorted graphics from commercial monitors
  2. Use the Gefen scaler to preserve aspect ratio, but at the expense of somewhat fuzzy graphics.
  3. Spend a King's Ransom on a marine monitor which may or may not work.
The plan is to pursue #1 and live with the distortion.  If I can't get used to that, then I can always add the Gefen scalers and do #2.  I figure I'll acclimate to the distortion easier than overall fuzzy images, but time will tell.

The final choice is a Samsung S19C450BR.  Partly because it's one of the monitors that I haven't returned yet, but more because it dims closer to zero than the others.  It also looks like it will be easier to mount than others, and at 16W it's pretty energy efficient.

Link to next article on monitors

Grand Banks ready for the season

Our Grand Banks is now in the water, operational, and ready for the season.  The final work was just routine maintenance that I hadn't quite finished.  The main engine and generator on-engine fuel filters needed to be changed, and the impellers needed to be replaced.

There are lots of different schools of thought on impeller replacement.  Some people run them for years before replacing, and some even run them until they fail.  If you use a boat year-round the impellers can indeed last a long time, but when the boat sits for 6-8 months, the impeller more permanently takes on the shape of it's last position, and begins to stiffen up.

The picture below shows the generator and main engine impellers side by side.  You can clearly see how the fins are bent over to varying degrees based on it's position in the eccentric pump chamber.  These impellers would probably be fine for another season, but replacing them proactively is an easy way to avoid an unpleasant breakdown at sea.


Generator (small) and main engine (large) impellers

If an impeller fails, it can be a real pain in the butt.  Now you need to make a repair while at sea, in a hot engine room, while the boat rolls and wallows and everyone pukes.  But to make matters worse, when they fail they typically send scraps of impeller bits down the plumbing path where they get trapped and block flow, typically in a downstream cooler.  So unless the impeller comes out 100% intact, you need to start taking the plumbing apart to fish out all the shrapnel.

And even if you change them at the dock in the comfort of a cool boat, it can still be a bear of a job.  Take another look at the picture above.  The smaller impeller from the generator is not too difficult to replace, but it's still a tedious process to get the impeller in the pump housing and on the shaft keyway, get the sealing o-ring to stay in place, and get it all bolted back together with out the o-ring or something else slipping out of place.

Now try doing it with that giant impeller off the main engine.  And try it on the engine where the pump is on the outboard side of the engine accessible only via a narrow space.  After struggling with this for three years now, I think I've finally refined a technique that works pretty well, or at least as good as it will get.

The first lesson is to remove the whole pump so the impeller can be changed out on a bench.  This is particularly important on the Cummins QSC engines since the electronic control assembly is strategically located to interfere with the impeller as it's drawn out of the pump body.  It's a design by someone who has clearly never changed the impeller on one of these engines.  I think design engineers should be required to personally perform every repair and maintenance procedure on whatever they build so they can see what they have wrought on the rest of us.

Anyway, it's a pain to remove the pumps, but easier in the long run.  Once on the bench, the impeller needs to be extracted from the pump body.  With the little pump on the generator you can pull the impeller out by hand or by gripping with a pair of pliers.  But you will never get this monster out that way.  Instead, it has a threaded end which is visible in the upper photo.  That's used in conjunction with a jack bolt to pull the impeller out, and beleave me, you need it.  That's either a 7/8" or 1" bolt (I don't recall which exactly), and it needs to be run in all the way before the impeller is free enough to pull out by hand.  The below picture shows the impeller with the jack bolt screwed into the top.

Impeller with jack bolt

Getting the impeller out is the easy part.  Getting the new one back in is a whole other story.  With the little one, a little twist and squeeze is all it takes.  The fins are small and pliable enough to not put up too much resistance.  But you can forget about that with the big one.  Even if you manage to get the tips of all the fins into the pump body, the moment you let down your guard the whole thing will spring right back out.  It's not until the impeller is a good half way inserted that it will stay in when you let go.  In past years I used a giant zip tie to compress the fins and help get the impeller inserted.  This helped, but wasn't great.  This past winter I did a car engine rebuild for the first time in over 30 years and that reminded me of the piston ring compressor I had recently used.  It seemed like a perfect way to hold all the impeller fins in place and compressed enough to slide it into the pump body and onto the drive shaft.  This compressor is nothing more than a long steel band about 4" wide that is wrapped in a circle like a corset, and it has a ratchet to pull it tight around the piston and compress the rings which otherwise want to spring out just like the impeller fins.

So off I went to get a ring compressor and 30 minutes later and $15 poorer I had the solution to getting these giant impellers compressed and installed.  It worked great, and I highly recommend the technique to others.

With the fuel filters changed and the impellers replaced, it was time for the water.  The yard finished up the bottom paint, and at 8:00AM Friday, in she went.  Once in the water, Laurie started organizing the boat for use, and I went through the start up and check out of all the remaining systems.  First was to ensure the sea cocks were open for the main engines, then start them one at a time, ensuring there was raw water flow, oil pressure, and checking for leaks especially around the water pumps which were removed for impeller replacement, test the gears, etc.  Then I did the same for the generator, and once running I proceeded to test out the air conditioning, electronics, etc.

Last step, after verifying that everything was working, was to update the software in the electronics and to update the electronic charts.  The only update for the electronics was for the Maretron displays.  They do a good job with fixing bugs and enhancing functionality, so there are updates a few times a year.  I wish there were an update for the Furuno MFDs, but still nothing.  So all I had to do was update the electronic charts.

Later this week we'll do a proper sea trial in conjunction with moving the boat over to our mooring, then early next week we are off to Mystic CT to pollute the gene pool at the Nordhavn Rendezvous.