Engine RPM variation (again)

As Gwen wrote yesterday we were finally ready to head off on our journey down the Pacfic Coast, trying to catch an elusive and narrow late season weather window. We were a bit nervous prior to departure as the forecast were for gales and small craft warnings down the Strait of Juan de Fuca. The worst of it was to be right at the Eastern end, so we made a pre dawn departure to, hopefully, avoid the worst.

When embarking on a trip like this, particularly with the possibility of encountering bad weather, you do not want to hear your trusty Lugger diesel engine begin to slow down spontaneously. We thought we had resolved the RPM variation issue by replacing the fuel flow sensors, as I described last week. Apparently not. It only took a couple of cycles of this to realize we weren’t going anywhere.

We didn’t make it very far…

OK, now you know what happened. If you don’t want to read a bunch of geeky stuff about trying to fix fuel flow issues with diesel engines, this might be a good place to stop.

Because this is an ongoing issue, I pulled out my phone to capture some video of what was happening. I compiled a short compilation of those clips in hopes that it will be helpful in trying to diagnose and finally resolve this problem. I’ll include a link at the end of this post.

What we saw and heard

  • While cruising at our normal 1800 RPM, a spontaneous drop of > 200 RPM, which was very obvious listening and watching the tachometer. The engine would slow down, stay at lower RPM for a moment, and then speed back up to the “right” RPM. Several instances of this are illustrated in the video. We also saw this when running at Wide Open Throttle (WOT).
  • As this was happening, the Maretron display showed large fluctuations in fuel flow as recorded by the inline sensors. It looked like the decrease in RPM was associated with an increase in reported fuel consumption, but it is hard to be certain because the system averages readings over a 5 second window.
  • There did not appear to be any fuel restrictions as would be measured by the fuel supply vacuum gauge, which is mounted on the fuel filter manifold. In fact, the reading we saw on the gauge was 0, surprisingly low, and meaning no fuel restriction.

Troubleshooting and attempted fixes

Diesel engines are pretty simple and very reliable. According to Wikipedia:

The diesel engine (also known as a compression-ignition or CI engine), named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to the mechanical compression (adiabatic compression). This contrasts with spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to petrol), which use a spark plug to ignite an air-fuel mixture.

Wikipedia

Diesel mechanics say that 90% percent of issues are due to fuel delivery, so we decided to work our way through the fuel system from supply to return in order to identify and eliminate potential causes. Here’s what we did:

  • Inspected and replaced the Racor primary fuel filters. These are the first stage of filtration, making sure that the fuel to the engine is clean. If there is contamination in the fuel, these filters remove it. They eventually need to be replaced. The indicator is the vacuum gauge I mentioned earlier. There was no symptom of high vacuum, but the filter had not been replaced since we started our trip to Alaska, so we replaced it. By the way, the system actually has two filters, so if one gets clogged you can easily switch the the backup.
  • Replaced the Lugger secondary fuel filter. This one is mounted on the engine and is the final stage of filtration. It was replaced this summer while we were in Alaska but had not been replaced since the tanks were inspected and the sensors installed, so we did this one as well.
  • Inspected and cleaned the Algae-X filter, which is some odd contraption that a previous owner had added. It is essentially a housing with a magnet in it, through which the fuel passes on the way to the engine. I suppose it is yet another stage of filtration, but it is entirely unclear that it actually does anything. Nevertheless, we disassembled and inspected it. All clean.
  • Having done all of this, and “bleeding” the fuel system to make sure no air remained in the system after changing filters, we started up the engine. We ran it up to 1800 RPM at the dock, and still saw the RPM (and fuel flow display) variation, even when the engine was running in neutral under no load. So, clearly none of these items were the cause of the problem.
  • Next, on the advice of the knowledgeable mechanic that replaced our fuel flow sensors, we “bled” the high pressure side of the engine, which involves loosening the fuel injectors while the engine is running to ensure that no air is trapped in the system. This had no effect – same symptoms when running at 1800 RPM at the dock.
  • Finally, we bypassed the Maretron fuel flow sensors using a couple of fittings to connect the fuel supply and return lines, respectively.
The diesel supply and return lines going in to (and coming out of) the Maretron fuel flow sensors. We put fittings in place to bypass them.

At this point we were out of ideas, so time for a sea trial. Unfortunately, the variation was still present… smaller and far less frequent, but noticeable both by the sound of the engine slowing down and watching the tachometer needle drop and rise back up. This time it seemed to be less noticeable at cruise RPM, but clearly evident at WOT (as shown at the end of the video). So, I think we can conclude that the Maretron sensors are not themselves the cause of the RPM variation. Now we need to turn to the fuel system on the engine itself, perhaps the fuel injector pump or even the injectors.

Bottom line… back to the yard. We plan to limp over to Philbrooks in the next day or so, which will be our new jumping off point for the trip South.

Here is the YouTube video that illustrates the issues: https://youtu.be/UFkKP2qk-AI

Best laid plans ….

After some late night and early morning detailed weather reviews, we cast off the lines and headed out toward the Strait of Juan De Fuca and Neah Bay.

The condo and slip in the rear view mirror

The weather was beautiful and calm and it looked like we would beat the northerly winds by heading west out the Strait.

Well, the gods, or maybe the furies, are not smiling on us today. Or maybe they are by having us face this engine issue before we are out at sea.

Only a mile outside of the marina the engine showed very significant RPM decreases. This only had to happen a couple of times for us to make the decision to turn around and head back and figure out what the heck is going on.

So we are back in our slip. Larry and Steve spent the day going through all the easy to fix and diagnose items like fuel filter clogs, taking the fuel flow monitors out of the circuit, etc. We thought we might have fixed it and took the boat back out to trial it, but the spontaneous RPM variations continued.

We will be making a trip to the yard for diesel work rather than down the coast over the next few days.

More to come as we figure out what the situation is.

The best laid plans of mice and men often go awry. Robert Burns

Preparing to depart for Mexico (still)

I am writing this on Friday, September 20th, which was to be our departure date for heading down the Pacific Coast to California and then on to Mexico with the 2019 CUBAR Rally. Well, things have not gone quite according to plan, and it is kind of a long story, so go grab a beverage, sit back and relax (or go read something more interesting).

I am sure that many wise and experienced boat owners have said something along the lines of “Never have major boat work done just before a big trip”… I think we now know why. As I mentioned in an earlier post, we put Miss Miranda in the yard right after returning from Alaska with what somehow became a lengthy project list. The good news is that the vast majority of the work was executed flawlessly and we are very happy with the improvements. The bad news is that a couple of items were not quite right, and they are critical. I know those same wise boat owners also said “Make sure you do a sea trial with the yard before leaving to ensure that EVERYTHING was completed to your satisfaction”. Good advice. Why didn’t I think of that?

The biggest issue that we discovered was a problem with the newly installed fuel flow monitoring system. This is intended to display the engine’s fuel usage and economy while underway. On diesel engines, fuel passes through the engine and about 20% is actually burned. The system uses sensors that measure fuel flow to the engine and back from the engine and from that computes fuel usage. While on our way back to Anacortes, we noticed that the fuel burn readings were very erratic while we were running at a constant RPM, and that the engine RPM was varying slightly… but enough to be a concern, as it had never happened before. To make a long story short, the sensors installed were undersized for the engine.

We found another issue as we were fueling up for the trip. We let the fuel level on the boat get really low on the way back from Alaska so that we could have the tanks inspected. They were in great shape, and the fuel was polished and returned to the boat. We measured the remaining fuel to calculate how much we needed to take on using our “tank tender” system. All went well until we came to the starboard aft tank, which measured as empty. We started filling the tanks and almost immediately got fuel flowing back from the vents. That is obviously not what is supposed to happen. I crawled into the lazarette and discovered that the sender from that tank had been broken off. The empty reading was false, and the tank was actually full (or very close).

The broken tank tender fitting.

The yard’s response to these issues was great – they arranged to have a technician come to us in Anacortes to do the repairs. Fortunately, I was able to secure a pair of the proper fuel flow sensors locally, because they were on back order from the Maretron factory. So far, all good with our tech scheduled to arrive on Wednesday morning.

Then I made a very unpleasant discovery in the engince room. There was a line of red fluid across the floor which seemed to be coming from the wing engine. It turned out to be Automatic Transmission Fluid from the gearbox. Not good.

Uh oh…..that is not supposed to be there.

The mechanic arrived on Wednesday and took care of the fuel flow sensors and the tank tender, and then turned his attention to the fluid from the wing engine. The diagnosis was bad main seals (that go around the propeller shaft), and the bad news was that it was not possible to replace the seals or rebuild the transmission. We had to either buy a new transmission or put a drip tray under the transmission, keep a large supply of fluid on hand, and hope for the best. Lenny, our technician, had replaced these units before, and assured us that he could replace ours pretty quickly. It turned out that a shop down in Everett had one in stock, so off went Gwen for a little ride to pick it up. It was late in the day by the time she got back, so we planned for an early start the next morning.

A brand new ZF/Hurth V drive for Miss Miranda’s wing engine.

Of course, nothing goes quite as planned… the old transmission did not want to come off, and in the struggle to remove it, Lenny cracked one of the mounting plates. Furthermore, I was told that Lenny needed to get back to his regular clients and would have to leave, finished or not, at the end of the day. Some discussion with the transmission shop led to a solution for removing the old transmission, but involved yet another trip to Everett for Gwen.

More parts for the V-drive

Lenny was finally able to remove the old transmission and got the new one painted while we waited for Gwen to return. Amazingly, he was able to install the new transmission, align the prop shaft, and test the wing (at the dock) and still make his 4 PM ferry back home. Lenny is an outstanding marine technician, and we greatly appreciate his mechanical wizardry.

As all of this was happening, we had a call with our weather router, who suggested that we delay our departure until (at least) Sunday to avoid a frontal system moving across the Washington offshore waters. We were not unhappy about this, as all of the unexpected repairs had put us behind schedule in loading up the boat.

We got out on the boat for another sea trial on Friday 9/20. It was all good news. The wing engine worked flawlessly, and the fuel monitoring was much more consistent, with no more RPM variation.

Fuel flow monitoring… it works!

Now we are busy with the final preparations and waiting on the weather window. We have another call with our weather router today (9/21) to determine if we are still on for a Sunday departure.

Back to the Boatyard

They were expecting us at the boatyard. No valet parking however.

We are here in Sidney, BC waiting to meet with our project manager for our final visit to Philbrooks before heading South down the Pacific Coast. We planned this visit earlier in the year, knowing that we could not get all of the work done before taking the boat down to Seattle for Opening Day in May. Therefore, we prioritized the work we thought needed to be done before Alaska and that which could be done afterwards. And, of course, we knew that unexpected items would turn up on our Alaska trip…. and man,were we right about that.

Waiting for her “spa days”.

The work list contains a mix of preventive maintenance items, repair or replace items, and a number of upgrades. Here are some of the things we wanted to do specifically related to cruising in Mexico:

  • Solar panels. We are adding about 1000W of solar on the pilot house roof. We had originally hoped to have these in place before heading to Alaska, but they got bumped to this visit.
  • Flopper Stopper setup for at anchor stabilization. We have heard that many of the anchorages in Mexico are exposed to swell and thus quite rolly. The flopper stopper is a rig consisting of a pole that swings out from the port side of the boat with a line that goes down to a plate deployed into the water. The plate has slats in it that allows it to sink easily, but not rise, thus minimizing side to side rolling. Many Nordhavns have this setup.
  • Interior DC fans. We do have four zones of Air Conditioning on the boat (which is one of the preventive service items) but we want to minimize our use of it, because it requires either running the generator or being connected to shore power. Therefore, we are going to place 8 fans in the salon, pilot house and staterooms with the goal of maximizing air circulation.
  • Sun Shade for the boat deck. When we put the dinghy down, there is a large amount of usable space on the boat deck. We will rig a sun shade to maximize the use of the space.
  • A second autopilot system. We already have redundant GPS, Chart plotters, and radar. We think it is also important to have a back up for the autopilot.
  • Replace galley refrigerator and convection/microwave oven. We planned to replace the refrigerator, which is a 20 year old domestic refrigerator and a real energy hog. We did not anticipate replacing the convection/microwave until the beginning of this trip, when the touch panel of the existing unit failed. It mysteriously started working again, but just to be sure, we will replaced it while we can.
  • Upgrade the engine room cooling system. Engine room cooling has been an issue with many Nordhavns. With a dry stack exhaust system, there is a lot of heat that needs to be removed via air circulation, and without proper circulation, the engine room can get quite hot… sometimes hot enough to impact the reliability of some components. The typical specification is that the engine room temperature does not exceed the outside air temperature by more than 20 degrees. We don’t meet that goal even operating up here in the Pacific Northwest, with very cool seawater for the keel cooler and low ambient temperatures. So, we are going to follow the lead of other Nordhavn owners who have installed extraction fans up in the stack to pull the hot air out of the engine room. We will also replace one of the existing blowers that failed on our Alaska trip.
  • Haul the boat out of the water and look at our propeller and bottom paint and do any service required. We didn’t hit any ice or logs of significance so we believe the propeller is in good shape but want to be sure.
  • Maybe… figure out a stern anchor solution. We have heard that a stern anchor is somtimes helpful in open anchorages in order to keep the bow pointing into the prevailing swells. We have a spare main anchor (a Fortress SX-55) that we have used once as a stern anchor, but the time taken to assemble it and drag the rode from the foredeck storage box makes it very inconvenient to use as a stern anchor. It would be nice to figure out a way to have a smaller anchor that is easy to deploy from the back of the boat.
When the boat is hauled out it is in a cradle like this. The first time we came to Philbrooks we actually stayed for a night in the boat when it was in this position! A bit tricky climbing on and off.

I think that does it for the “planned” work. Some of the repair or replace items that came up on our trip North include:

  • Patch the tube on the dinghy. We were in Prideaux Haven going to our favorite swimming hole and preparing to anchor the dinghy next to a large rock. The rock had numerous oyster shells that were exposed at low tide, and we drifted into one that made a two inch gash in the tubing.
  • Replace the motor on the diesel heater. We rarely use the diesel hydronic heating system in the summer, but needed it on one 40-something degreee morning in Alaska. Of course, it didn’t start. Some great support from Sure Marine Service in Seattle helped dignose the problem, which was the motor. The diagnostic tool? A rubber mallet. “Start the system, and rap the motor with a rubber mallet. If it starts up, you know you have a bad winding and the motor needs to be replaced.” Yup.
  • Replace the Furuno GPS. We have three separate GPS sources on the boat including this older Furuno GPS, which connects directly to a Furuno RD-30 display unit to show speed over ground, position, wind data, etc. When we were crossing Cape Caution on the way up to Alaska, the GPS stopped transmitting data… of course when the seas were up and the boat was moving around quite a bit. No big deal to switch to another source for the NAV equipment, but time to replace the old unit. I elected to replace the receiver only and still have it connect to the RD-30, and from there the NMEA bus.
  • Replace the generator injector pump. I mentioned this in an earlier blog post and actually got a replacement pump sent into Petersburg. However, the fuel leakage had decreased to an acceptable level, and seeing that a miscue in removing or replacing a connecting clip would have serious consequences, I wimped out and elected to have Philbrooks do this.
  • Add delay switches to the windshield wipers. This one sounds odd, I know. The boat has four wipers, one across each piece of the pilot house windshield. The wipers are needed for rain, obviously, but also for clearing salt spray in boisterous sea conditions. Each of the wipers has a separate 3 way switch for off, low, and high speed. In all but hard rain (which we had plenty of in Alaska), the low setting is still too high. Thus, one will be constantly switching the wipers on and off. Trivial, but annoying when running in crummy weather. We should have done this before going to Alaska, but it was only when we got up there that I realized just how much of an annoyance this was, and how easy it is to fix. Just add $$.

After a full day of meeting with the various departments at Philbrooks, everyone has a good idea of what needs to be done, enough so that we have established a tentative pick up date… September 13th. If all goes well we will take the boat back to Anacortes, load it up and start heading South on September 20th.

Service Opportunity Karma

I am thinking that maybe I should not have made the service opportunity blog post. It seems to have prompted new service opportunities. The current one has to do with the… shall we say… sanitation system. Most of us living on land rarely give this topic a thought, but it is very important on a boat. In our home cruising grounds all Marinas have pump out stations, where we can remove waste that accumulates in our holding tank.  That is not the case way up here.  Therefore, boats are equipped with an overboard discharge pump, which does exactly what the name implies, of course only in locations (offshore, deep water) permitted by Coast Guard regulations (and common sense).

So, what to do if said pump does not appear to be in working order? Check all of the easy possibilities first… maybe the vent is clogged, maybe the through hull is blocked, maybe the tank tender is not reading correctly. When that is done, you recall that you had the system serviced in May, wanting to avoid just this situation… and you also recall that you do not have a replacement pump or spare parts on board. Uh Oh. Fortunately, we have both phone and data service where we are, so I was able to look up the model numbers for the relevant parts and call Piston and Rudder in Petersburg to see if they can order the pump and/or parts for me. I feel that I am getting to know them quite well, since they also ordered the generator fuel injector pump for me.

We should find out today if they can order parts, and we plan to be in Petersburg by Thursday or Friday. Then the real fun can begin…

Meanwhile we are enjoying beautiful Takatz Bay (post coming) and a couple of sunny days.

Maintenance and “Service Opportunities”

Routine (and not so routine) maintenance is part of the joy of boat ownership. For instance, our main engine requires an oil and filter change every 250 hours and our generator requires the same every 200 hours. We carry the necessary spares and supplies, and I did the generator in Hoonah and just did the main engine the other day in Sitka. They are both plumbed into an oil change pump, so it is really easy to do – the biggest issue is properly disposing of the used oil and filters. Fortunately, most Alaska ports have oil disposal tanks.

While doing the generator oil change I noticed some fluid collecting on one of the motor mounts. Not sure of the source, I cleaned it up with an absorbent pad and decided to keep an eye on it. In Sitka it became clear that it was a fuel leak coming from the injector pump.

The injector pump assembly. The pink stuff on the lower right, under the bolt, is diesel fuel. This is a “service opportunity”.

Coincidentally, I had gotten a call the day before from Northern Lights diesel guru “Lugger Bob” Senter to discuss an inspection of Miss Miranda in preparation for the CUBAR rally. I called Bob back and he was able to diagnose the problem over the phone. The cause of the leak was likely that the inner o-rings on the pump became stiff and lost their ability to seal. Basically, time to replace the injector pump and have this one rebuilt, as the o-rings are not user-serviceable. I did not have a spare on hand, but called the local Northern Lights dealers. The dealer in Sitka probably could have gotten a replacement here in a day via “Gold Seal” delivery – basically putting the part on an Alaska Airlines flight, but at a cost of $100+ in shipping. I elected to have the part shipped to the Petersburg dealer, as we will be there in a week.

The only other “service opportunity” we’ve dealt with recently was with the ABT Trac stabilizers, which mysteriously went into “SAFE MODE”. Trac service Guru Dave Wright was able to diagnose that issue as a failed “roll control” unit, which we had shipped into Juneau while we were there. That was a very simple part swap and configuration job.

I’m glad that our scheduled maintenance is behind us, and am hoping that we don’t have any more service opportunities.

Update: Self-inflicted “service opportunities “

So, getting ready to depart Sitka this morning, go to start the engine and…. nothing. Crank crank crank, no start. Almost NEVER happens with a Diesel engine. And almost always a fuel issue. So, I checked all the obvious things, and even some difficult to get at non-obvious things (bleeding the injectors) and still nothing. Oh, and I was missing the proper wrench for the injectors. Fortunately, another Nordhavn owner was able to lend both a tool and some experience. Two things. 1) There is a manual fuel pump to prime the system after changing filters, but it only works if the crankshaft is in the right position. 2) it is best to only bleed one or two injectors and not try to do all six. Finally, metric 17 mm for the injectors, and better yet a “crows foot” wrench… look it up. End of story- engine started, all good, now underway. Thanks, Jim!

Electrical System Repaired!

We got to Petersburg yesterday and got a list of service providers from the Harbor Master. This morning I called Mattingly Electric and by 9 AM Darby was on the boat. He cut off the bad ends of the old wires and managed to locate the proper breakers, grumbling a bit about the flimsy plastic box and how tight the fit was. Well, he got everything wired up and as he was pushing the whole assembly into the box, the case of one of the breakers cracked.

This would not do. He left and assembled a heavy duty metal box and mounted it on the generator sound shield, as shown below.

The new breaker box

Inside are non-marine, but much heavier duty, 50 Amp, 250 volt breakers.

Much more robust breakers.

This seems to me to be a much better solution. It is easy to access and replace the breaker, if necessary. We are running the generator right now and everything seems to be working normally (and nothing is burning).

We are actually on a maintenance roll today. I got Gwen a 29th Anniversary gift, which was just what was needed to clear the clog in the insinkerator unit that we use to dispose of food waste.

Happy Anniversary honey!

Finally, a surprising number of people have asked about the water pump issues. All resolved by installing the little Jabsco Par Max pump that was bought 9 years ago as a spare by the previous owner. Here’s a rule of thumb… if we aren’t griping about something, that means it’s OK (or we have bigger issues to worry about).

Now it’s time to explore Petersburg.

Electrical System – a scary failure

Yesterday we departed Stedman Cove for Cannery Cove. We often run our generator while underway, allowing us to run the water maker, charge up the batteries and do laundry. Today was no different… except that I noticed that the water maker stopped running. When Gwen went back to check, she noticed an acrid electrical smell. I went down to the engine room and saw no smoke, but then I noticed that we had lost one leg of our 240 V AC power from the generator. I quickly shut everything down and went to investigate. I suspected a problem with the main AC circuit breaker from the generator. Sure enough, it was tripped, and the box was hot… and looked like it had melted a bit. We decided to keep moving on to our destination and investigate further once we arrived.

When we got to Cannery Cove, I opened up the breaker box and found that one of the connectors to the breaker had burned right off – see the photo below. The breaker showed clear signs of overheating and the box had indeed melted on that side. Furthermore, the wire insulation (at least) had melted and essentially fused all of the wires together. We are DAMN lucky that we didn’t have an engine room fire.

The culprit was quite obviously a loose connection on the post that burned off. You can clearly see in the picture below that the screw holding the connector to the post is loose. Loose connection = high resistance = high temperature = electrical fire.

So, what to do? We are off to Petersburg today to see if we can buy or get shipped in a replacement circuit breaker. I did not have a spare for this breaker, nor do I have the connectors or crimping tool for this heavy gauge AC wiring. Lesson learned, both in terms of spare parts and tools.

Oh, by the way… it is our 29th wedding anniversary today. I did promise Gwen that we would spend it cruising, but forgot to add that the definition of cruising is repairing the boat in exotic locations.

Riding the ebb, water pump woes and how thick is a Nordhavn hull?

Riding the ebb tide up Johnstone Strait the other day we saw a boat speed of up to 15.1 knots… and our normal cruise speed is 8.6 knots. That’s a hell of a push. I was too slow to get evidence of that, but this is pretty close.

The boats shown on AIS at the top right of the chart were getting ready to start the Van Isle 360 Regatta.

After arriving at Port Harvey, Gwen said that our domestic water pump wasn’t working…. AGAIN. It never completely shuts off, ticking over very slowly after all faucets are shut… as if there was a leak somewhere… but there isn’t. We turned the pump off, deciding we would deal with it in the morning.

Yesterday morning I woke up bright and early… to an impressive bout of gastroenteritis. It was not fun, and knocked me out for 24 hours. Glad that is over with.

  • This morning I went back at the water pump. I decided to install a small accumulator tank, hoping that might help. This is when I came to consider the question of how thick is a Nordhavn Hull? The answer(s)?
    1. That depends on where you measure.
      Not as thick as I thought.

    I was drilling a hole to mount the accumulator pump – and was planning to use a 3/4″ screw. In went the drill and out came a stream of water. Yes. Salt water. A short screw coated with 3M 5200 sealant went in pretty quickly and a bunch more was slathered on over it. Disaster averted. So the real answer is, at least where the water pump is mounted, no more than an inch thick.

    After all of that excitement, we still didn’t resolve the water pump issue. Accumulator tank did not fix the problem. I replaced the pump with a spare. Nope. Now we are back to wondering if there is a very small leak in some out of the way spot. We decided to leave it for now and simply turn the breaker on when we need water and off when we’re done.

    Today we are resuming our journey north,heading for Sullivan Bay in the Broughton Archipelago. Gwen did quite a nice job of getting Miss Miranda off the dock and underway.