Duncan from Puget Marine Electronics came out for a few hours to investigate. We cycled all of the AC devices, but could not get the breaker to trip. North Pacific offered to replace some components, but given how intermittent the failure is, I’m loath to tear apart a perfectly good system to try and track down what is a relatively minor (though potentially problematic) fault. Without a repro case, it’s very difficult to figure out what is happening. I had a theory that we might measure the AC devices one-at-a-time to see if any of them are leaking a small amount (as an indicator of maybe a bigger leak during some cycles) but the wires are noisy enough that it’s hard to track those milliamps via a handheld meter.

Duncan proposed building a monitoring rig and temporarily installing it on the shore power connection. This would log all power use so if/when the fault happens, we have the log data. Seems a good plan. We’ll have hard data to help track down the fault and we don’t need to replace what are likely perfectly good components. The Magnum Inverter/Charger has no logging at all, so it would be nice to get some visibility. Bill from North Pacific also kicked around moving us to a Victron system. He’s a huge fan of how configurable they are; but, again, I’m not going to tear out a perfectly good Inverter/Charger to track this down. There’s a very good chance we’d replace the unit only to find the failure was some tiny short somewhere. The downside of this is it could be months before it happens again. Log storage could be an issue.

Boat Internet

I really hate boat internet. I have been limping along with a relatively simple system based on the Netgear modem Steve recommended. It worked great until Verizon unceremoniously cancelled my plan and put me on some lame 15GB plan that seems to top out almost immediately. Verizon has really driven customer service to astonishingly new lows.

I’m now ready to install a real system using some of the more updated components recommended over at SeaBits (Steve is a national treasure for cutting through all the BS with these system designs). Someday soon, I dream that a company will come along and offer unlimited broadband over LTE, and all of the companies squeezing people with byzantine plans and absurdly low data caps will lose all of their customers and all of their revenue. On that day, the schadenfreude will be delicious.

Trevor sourced the spares for the thruster and I arranged for a diver to replace the prop. Looks straightforward. “Now I understand one more system a little bit better!”

The propane failure was weird. I called Trident and they have never heard of this failure mode. Basically, there seems to be a short in the data connection wire on the pigtail from “Alarm A”. So, when it starts up, it goes into alarm almost right away. Why this would start suddenly on a Saturday evening when we haven’t been using the propane system, I don’t know. Actually, if the short is in the pigtail, the jumper I put in shouldn’t work. Trident confirmed that all three pigtails (Alarms 1-3) are all soldiered into the same spot on the board – so they should behave the same unless the fault is in the wire.

Regardless, I hooked the detector up to “Alarm B” and put a jumper on “Alarm A”. The propane flows fine and the solenoid opens and closes. I also tested the alarm by putting a little butane on a paper towel and waving it nearby and that works fine as well. Honestly, I am stumped. I don’t like having a system failing for reasons I don’t understand. Especially when it also recovers, for reasons I don’t understand…. Trevor offered to send me a new kit, but I am going to leave it for now and try to avoid the dreaded “maintenance induced failure”.

I got the battery specs from Trevor. The batteries are pretty tough and accept a wide range of voltage inputs. Other than shore power float being a tiny bit low, everything is within spec. Also, since the solar panel float voltage is at the high end of the range, the two together should balance out.

Max Bulk Charge RateAbsorbFloatNotes
Battery Mfg. Recommended40-50% “higher possible”14.25 – 14.613.6 – 13.8
Magnum Shore Power Charger “AGM”132 (observed)14.513.5Float is a tiny bit low.
Solar MTTP “Sealed”??? Nothing observed14.413.8

Note that temperature has a big effect on these ranges as well.

The ELCI breaker tripped again. This is the third or fourth time it’s happened. The good news is we have more clues, but the bad news is it’s still going to be hard to troubleshoot.


  1. This happened early on when the boat was being commissioned, so it started happening before I brought any of my devices aboard.
  2. It’s happened on both the forward and aft ELCI breakers. The errors were slightly different, though. The last time, it was the forward breaker and the green light was flashing, indicating an over current. This time, it was the aft breaker and the red light was illuminated, indicating a ground fault condition.
  3. It’s happened with both the 50-amp cable and the modified 30-amp cable. The bridge between the poles on the 30A was a culprit, but we can rule that out.
  4. It’s intermittent, so it’s likely from something that’s cycling.
  5. The batteries were fully charged – I know this from a prior check on the boat. For some reason, the charger hit the 12 hour max charge time limit, which was weird, but I had been mucking around with the settings recently, so it was likely related to that. In other words, the shore charger would only have been running float cycles – no bulk or absorb cycles.


  1. It’s the battery charger. This is my top guess since there are some weird interactions between the shore power charger and the solar charger. The shore charger will cycle on and the conditions that it cycles on in will vary due to the battery state of charge, the relays to other banks being opened or closed, and the input from the solar charger.
  2. It’s the fridge. This is my second guess – only because household appliances are often implicated in these errors. The fridge has a compressor that cycles on and off. If it is losing a very small amount of current and occasionally surging over the 50mA threshold, it could cause this.
  3. Inverter. Even though the inverter was off in all cases, it’s still in the circuit between the shore power and the boat. The inverter switches its ground depending on whether it’s passing the AC power through or creating AC power from the batteries. This seems less likely to me since it’s a brand new modern inverter, but it’s possible.
  4. Watermaker. This is the only other item that is cycling. It comes on once a week to flush the prefilters. It’s a very small draw and seems unlikely.
  5. The 24V charger. This is a separate charger that runs off AC to charge the thruster/windlass banks. There’s no reason for it to cycle on after the boat has been hooked up to shore power for a week. Unlikely.
  6. There is some kind of fault in the wiring causing a bridge between the neutral and ground. This seems unlikely as it is a new boat and the problem is so intermittant (and happens when we’re away and the boat isn’t being used). I can’t think of a reason for a wiring fault to randomly manifest like this.

Troubleshooting and next steps

Bill and Duncan are going to help. The first step is to measure the AC devices and see if any of them are leaking. Maybe more than one is and it’s the two combined that are causing this (e.g. the water maker cycles on at the same time as the fridge or battery charger). The unfortunate part is, what do we do if something is leaking? Is it worth replacing an entire fridge – especially if the replacement has the same issue? I really like the full sized fridge, and none of the other NP owners have had this issue. If it is just a leaky system we could in theory install an isolation transformer. This would prevent the shore power from tripping – which at best spoils my food in the fridge and at worse could kill my batteries if I’m away for a while. But, it also just masks a problem we probably don’t want to ignore.

I actually hope it’s a wiring issue, since that can be fixed most easily (though extremely difficult to track down). Alternately, it could be a configuration issue with the battery charger. Not at all sure, so stay tuned.

Useful links

Single-handing the boat on an overnight seemed like an important milestone. I wanted to prove to myself that I could manage various jobs by myself and get a feel for what it felt like to be at anchor alone. This may sound weird to some, but I haven’t spent a night away from my kids in years. I am on vacation this week, so my wife and I coordinated things so I could take a 24-hour mini vacation and test my skills (and face some anxiety).

Over all, the trip was a success, with one big hiccup. I decided to circumnavigate our home island of Bainbridge and drop anchor in a place we’d never been. On Monday, I headed down the east side and across the south end and dropped the hook in Blakely Harbor. Blakely is sheltered from the north and south and has a very nice view of the city to the east. I anchored for the night, explored by dinghy, had a relaxing dinner, then turned in early. The next morning I headed up the west side and docked without incident. Conditions were perfect for a solo trip.

What went well

  • Got out of the marina and to the harbor with no issues. Pleasant cruise
  • Dropped and set the anchor with no issues
  • Dropped the dinghy and cruised around for a couple hours. Went tidepooling at Blakely Rock, visited a friend who lives on the water, explored Eagle Harbor
  • Moved and reset the anchor when the current shifted and I noticed a very slow drag. The Garmin anchor alarm is buried behind 30 menus, but once it is set up it works well. After the second set, I didn’t move all night. I’m much more confident about anchoring, these days. I still make mistakes, but they’re recoverable and I am learning how to read the signs of a well- vs. poorly-set hook.
  • Plenty of sun kept the batteries above 95% for most of the day
  • Relaxing evening with plenty of peace and quiet. Replaced doomscrolling on my phone with reading a book on my kindle.
  • Stowed the dinghy solo without issue
  • weighed anchor without issue
  • Saw my wife from the boat when she was out for a run along the shore
  • Backed into my home slip with a 10 kt. crossbreeze solo (a neighbor was on hand in case things went sideways – literally). The trick I learned here is to not worry about the “neighbor side” of the slip. If I am 1-2 feet away from the dock, I have plenty of clearance to my neighbor. So, I don’t need to check out both sides of the pilothouse. Also, when I am the correct distance from the dock it actually looks way too close from the pilot house. So, I need to get used to that.
  • Spent a few hours puttering around after docking – milked my vacation day to the max

What went poorly

  • There was really only one thing, but it was a big deal for me. When I moved the boat to reset the anchor, I was towing the dinghy. When I used the stern thruster to reposition, it sucked in the line connecting the dinghy to the boat. I was able to cut it away, but it broke two fins off one of the thruster props. I emailed Trevor, who has become a reluctant therapist, and he said this is a common failure mode and the props are replaceable in the water. All in all it wasn’t a big failure, but it was hard to forgive myself, since line handling and keeping them out of the water and away from props is one of the very first seamanship skills you learn. I’m not hard on myself for honest mistakes, but when I know better and screw something up because I was being lazy or on auto-pilot I get really annoyed.

Food for thought

  • I spent the whole night convinced I had damaged something permanently and wouldn’t be able to dock. In the light of day, I got a picture using my underwater camera and did some research. The breaker would have tripped before anything serious happened, and the prop is accessible enough that I might be able to replace it from the swim step. Every mistake is an opportunity for learning. This is a new failure mode.
  • I don’t have enough spares. Spare thruster props should probably be standard kit. Even without leaving lines in the water, thrusters suck in anything nearby, making this a likely failure. It’s very hard to dock without them, so I should have them aboard. I should also have a spare pin for the dinghy prop. There are a lot of rocks around, and it only takes one to break a prop. This dinghy has oars, but it’s just not made for rowing. A $2 spare pin could make all the difference. Spares and knowing how to use them turn big failures into minor inconveniences.
  • Lines are incredibly strong. The dinghy painter was about 1/4″, but my multi-tool knife couldn’t get through it. I had to use the saw and it took several seconds. I have a line knife aboard, but I don’t usually have it on me. This is probably a handy tool to keep on you, since, if you have to cut a line, something serious has happened.
  • The sound of an anchor dragging from the V-berth sounds a lot like the sound of the chain just rolling over rocks. Either way the sound is conducted right up into the main cabin. While in bed trying to sleep, I kept hearing the telltale sound of chain on rock. I went up to the pilot house a few times to check the chartplotter, but she was holding tight. I know a lot of people who put instrumentation next to where they sleep to help with this – something to consider.
  • Weighing anchor solo is easy, but if it’s muddy there’s really no way to wash it down. I went all the way home with a giant pile of mud on the anchor. Fortunately, the chain was clean, so it didn’t get into my locker.
  • I had had one drink before dinner when I noticed I might be dragging. For a 180lb man, it’s not really enough to impair my judgement, but I usually never drink when I have anything important to do. When I reset the anchor, I didn’t take the time to walk around and make things ship-shape (like securing the dinghy). Since things can and do come up on the boat, drinking on a trip – even when at anchor – seems like a bad idea. After breaking the thruster, I’m even more convinced of that. Of course, having a sundowner is one of my favorite parts of the day. But, I think I need a checklist of sorts to make sure I can be off the clock when I have one.

Critical gear for single-handing

Turtle is well-set up for single handing. I also need a couple of improvements.

  • Windlass control from the pilothouse with a chain counter.
  • Chartplotter with anchor drag alarm
  • Bow and Stern Thrusters with remote – so I can control it from the dock
  • Power davit for getting the dinghy on and off
  • Boathook – for many reasons
  • Forward gate so I can climb down to the dock from the pilothouse. The porthole from the midship head doubles as a step. This isn’t ideal, but since the only way to the stern is through the main cabin it’s still the most direct way to the dock and the fastest way to get to the midship line.
  • Underwater camera – I’m still using a cheap Panasonic I bought like 12 years ago and it still works great.
  • Todo – backup camera. The one they install by default is on the hardtop. This along with the relatively low resolution makes it pretty worthless. Putting one on the roof of the cockpit will make this a ton easier. My neighbor (NP42 Well Seasoned) has a wireless one that even has backup guidelines.
  • Todo – more spares

I also recorded a video – which may or may not continue…

This electrical system digression has had some unexpected benefits. Apparently, I’m not the only one annoyed by imperfect system integration. I can totally relate to his irritation.

I’ve been spending more time on YouTube (welcome to 2011). While I still feel like 99.9% of it isn’t interesting to me, there are still some great finds there. I may try some more videos, myself. Though, I’ll still be posting them on Vimeo. (These people are far more good-looking, though. I was born to communicate by the written word…)

I set the Max Charge rate to 90%. The charger specifications say that it will only pump a maximum of 125 amps into the batteries, but when we pulled into port and plugged in yesterday, there were 132 amps going in. The max charge rate (C/5) of 600 amp hour batteries is about 120. Now, the amp meter function of the inverter/charger (without the BMK) is only accurate to within 20%. Plus the solar charger may have been pumping in some amps. But just in case I bumped it down and it dropped to a much more battery-life-friendly 114 amps.

[EDIT – back in May I set max charge back to 100%. Per the specs, the batteries can take up to 300 amps during bulk, so 132 should be fine]

Next, I need to reconfigure the solar charger to match the charge profile of the shore power charger, and get rid of the monthly “equalize” function, which I think might be death for AGMs…

This is a bit of a long one, and I am still not done figuring it out. But, it was one of those issues that lead me down a rabbit hole, and when I came out the other side I knew a ton more about how the boat works. 

  • Thing #1 – When we were at anchor and the house banks were at 53%, the solar panels didn’t seem to be putting out enough charge. 
  • Thing #2 – After plugging into shore power at 77% SOC, the Magnum shore power charger just went straight to float (instead of bulk, as expected). The next day, the house banks were still only at 80%, but the charger said “battery full”. 

This lead me down a winding path of poorly-translated charger manuals, battery theory, and system integration philosophy, which I will mostly leave out here. But, here’s what I learned in the nutshell. 

When the batteries were low and I saw this on the charger:

I’m like, “Why aren’t the panels putting out as much as possible? Shouldn’t they be in ‘Bulk’?” The answer was, of course, that they were. “Bulk” charging just means that the charger is putting as much as it can into the batteries. In this case, the panels are generating 88.56 watts, which the MPPT charger is converting into something that the DC system can use, in this case 7.7 amps at 12.5 volts (though, how it’s converting it up to 96.25 watts is a question for another day). The voltage is determined by the resistance of the battery, not by some setting on the charger. So the charger cranks as much current (amps) into the battery as possible and the voltage builds as the battery resists the charge. In this case, the sun was still relatively low in the sky.

Lesson Learned #1 – The solar MPPT charger will push as much current into the batteries as it can up until the voltage hits the absorb setting (14.4v in this case). If the sun is low or obscured, it will be less than if the sun is directly overhead. I thought that the voltage of the system was a set value, but that’s only true when the batteries are charged enough that they create some resistance to the charging sources. Once that resistance passes the absorb threshold, the charger will hold the voltage stable and continue to lower the charge to keep it there.

Lesson Learned #2 – The reported voltage of the DC system is a combination of all of the load, all of the charge, and passive resistance of the various components.

In practice this means that the voltage I see on different components will be different. So, in this case, the panels saw 12.5v. But, the battery monitor saw 12.31v. So we’re seeing a .3v difference between the charge output and all of the resistance in the system (the batteries and any devices using power).

Since the battery monitor (BMK) is a shunt that is the last link between all of the negative bus items and the battery, it is the most accurate measure of the voltage on the negative battery terminal.

Note that the solar charger is bridged directly to the charging input on the positive side of the batteries.

So any current from the solar panels is combined with current from the charger.

Lesson Learned #3 – the reported current in the system will be different depending on where it’s being measured. This one really confused me. I was trying to do simple math – if the DC + AC loads are X (a negative number) and the solar panels are outputting Y, the the reported load on the battery monitor should be X + Y. Nope. While that’s generally true, there are so many devices on the system (all fluctuating) the numbers will not add up exactly. Ultimately, the battery monitor will tell you what is going into or coming out of the house bank. But, trying to add up the loads across the system is imprecise. However, it is directionally true. So, at one point, the sun got bright enough and the batteries were charged enough (we ran the generator) that the resistance (voltage) increased and we saw a net surplus on the BMK. This means the sun was charging the batteries enough to produce a small surplus (over the house loads).

Also, the components all measure with different levels of precision. From the manual: “The DC Amps meter displays the amount of current going in or out of the battery. A negative number shows the amount of current being removed from the battery. A positive number shows the amount of current delivered to the batteries. This meter converts AC amps to display DC amps, so the accuracy below one amp AC (~10 amps DC @ 12 VDC) is not detected. When the current detected is greater than one amp AC, the accuracy of this meter is ±20%.” I’ll trust the BMK more than the regular DC volts.

Lesson Learned #4 – There are race conditions between the three phase solar panel charger and the three phase shore power charger. Each are using different voltage levels and thresholds for absorb and float settings. Also, since voltage is a trigger, the charging volts from one system can cause the other to go into an incorrect state. In most cases, this just means that the chargers take turns doing what they can to charge the batteries, (backing off when the other one is working harder). In some cases, it can prevent charging.  This has been a problem for a while.

In our real-world example, we returned from a cruise at 77% SOC with tons of sun. When we plugged into shore power, the solar panels were producing enough current (20.9A) that the battery was resisting at 13.7v, so the shore power charger went right into float (13.3 volts at the shunt). This is by design! From the manual: “If the battery is >13.0 VDC… then the battery was already charged and the charger automatically goes to Float charging to keep from overcharging the batteries.”

The next day, the batteries were still at 80%, though the charger said “full” Once again, this was explained in the manual. “After four hours of float charging, the charger turns off and “Full Charge” displays (charger is now in Battery SaverTM mode). If the battery voltage drops to ≥12.6v… the charger automatically initiates another four hours of float charging.” But, what happened is, the solar panels + shore power float got the batteries to 80% (~12.7v), so the second float cycle was never triggered.

The best way to avoid this is to force a Bulk / Absorb / Float cycle when you first plug into shore power. There’s a function on the Magnum remote under CTRL to do just this. When I tried it, the charger jumped into bulk and very quickly hit absorb. Right now, the absorb cycle is set to run for two hours, which is about right to get from an 80% charge to float.

There will be other race conditions. This is exacerbated by the chargers having slightly different set points for their various modes and triggers.

Start Bulk IfStart AbsorbAbsorb timeFloatBattery fullSkip to float
Magnum<= 12.8v>= 14.5v2 hrs13.5v for 4 hoursafter 4 hours float*>=12.9v
Tracer<= 12.6 (?)>= 14.4v2 hrs13.8vNA – stays in float if possibleNA

*When in “battery full” mode. The Magnum will enter absorb if the voltage drops to 12.6 and bulk if it drops to 12.1. 

Lesson Learned #5 – System integration is hard. The Tracer MPPT Solar charger uses different defaults than the Magnum. The magnum was set to the “wrong” type of AGM (Lifeline) (though since these are OEM batteries, there are no specs immediately available). There are also a number of settings like maximum charge rate, Absorb cycle time, etc. that probably need to be optimized. Don’t rely on the default settings and don’t assume the builder/commissioner set it up right. Even solid boats with experienced owners get this wrong.

Also, for posterity, here’s the cheatsheet for charge level per voltage for AGMs.

  • 100% – 12.8v+
  • 75% – 12.6v
  • 50% – 12.3v
  • ‘25% – 12.00v

We just passed 100 hours on the main.

I’m not sure when the official one year anniversary is, since the way we did the financing we actually owned her before she landed. She splashed on 17-Jun-2020 and I first boarded her in Blaine on 20-Jun-2020. Commissioning was complete on 11-Aug-2020. Regardless, 100 hours in eight months ain’t bad for two people with kids who work full time.

Now that Turtle’s not a new boat any more, it’s time to turn my attention to the potatoes* of boat ownership – maintenance. I decided a long time ago to embrace boat maintenance (I still reserve the right to whine about home maintenance). I’ll quote myself from the manual I wrote for my old boat:

“The two happiest days of a boat owner’s life are the day they buy it and the day they sell it.” 

I hate that saying. Yes, boats need maintenance. The sea is relentlessly pulling her apart and it’s your job to make sure she stays together. How you address the need for this maintenance will determine whether you enjoy owning a boat or whether the old saw becomes true. You can either perform maintenance yourself, which requires time and patience, or hire someone to do it for you, which costs money…. But, ultimately, you’re the owner – and it’s not always easy to find someone to do the work. Someday you will be stuck somewhere with something broken (hopefully it’s something minor) and there will be no one around to fix it. Your goal should be to learn how do to as much as possible yourself.


This is part of why I fell in love with the NP: Everything is designed for maintenance. If it’s not stainless steel, it’s accessible and serviceable. Now, every NP is custom, which is really nice for BS-ing with other boat owners (“what’s she powered by?”). But, it also means they don’t really come with a manual. In fact, they come with several:

Note the stylish handbag…

Boat maintenance is a journey, not a destination. The more I learn, the more I realize I don’t know. I still make stupid mistakes all the time (last weekend I spent five minutes troubleshooting the outboard, only to realize I hadn’t put the clip on the auto-kill switch). This beginner mind is humbling, but it also leads to over-cautiousness and probably far more anxiety than it should. But, so far my approach of “do your best and ask for help” seems to be working.

So, what to do for maintenance? I have some experience with this on my old boat, but it’s hard to know when to follow the recommended intervals and when to disregard them. Cummins, for example, recommends checking the gear oil daily. The engine oil change interval is 250 hours or 6 months, whichever is sooner. So, these guidelines are clearly for a motor that is being used every day. But, the intervals can and should be different for one that sits for weeks at a time. This is one place where I feel like North Pacific could be a little more structured in what they prepare for owners. Even if every boat is unique, having some kind of guidelines – something like the book people prepare for putting a boat into charter – would be incredibly helpful.

Since that doesn’t exist, I’ll have to write it.

As with most big hard problems that I don’t know how to solve, the best place to start is probably with a simple list. For each system, I’ll crack the included manuals and leverage the community to figure out what the real interval should be (though asking for advice on trawler forum can be like asking a bunch of pre-schoolers who the best Avenger is…). I don’t expect I’ll ever be “done” with this. But, I expect in a few years it will stabilize.

  • Main Engine
    • Oil and Filters
    • Primary and secondary fuel filters
    • Inspect / replace pencil anodes
    • Re-torque engine mounts (there are no factory specs for this – any suggestions?)
    • Re-torque shaft couplings
    • Change gear oil
    • Flush coolant
    • Inspect belts
    • Flush aftercooler
    • heat exchanger (?)
    • Raw water pump (impeller)
    • fresh water pump (?)
  • Generator
    • Oil and filter
    • primary and secondary fuel filters
    • zincs
    • flush coolant
    • belts
    • heat exchanger (?)
  • Water Maker
    • clean /change media filters
    • change high pressure oil
    • change membranes (~10 years)
  • Dinghy
    • Change oil and filter
    • inspect prop (need spare pin)
    • charge / change battery
    • change plugs
    • anodes (there must be some in there)
  • Hydronic system
    • Fuel filter
    • Clean inside unit
  • Bottom
    • Inspect and replace zincs (2-3 x year)
    • Bottom cleaning (2-3 x year)
    • Bottom paint (~2 years)
  • Misc
    • Change fresh water filters
    • Inspect through hulls (open and close, look for rust)
    • Test bilge pumps
    • Test / Replace batteries
    • Thrusters (?)
    • Propane (fill and inspect)
    • Grease steering coupling
    • heads (?)
    • Grease windlass
    • Wax hull

*as in “meat and…”