Teaching Marine Electrical Seminar In Sausalito This Saturday

Clark October 25th, 2016


How many wrong things can you find in this picture?

If you happen to be in the Bay Area this Saturday, October 29th, I’m giving a marine electrical seminar at Spaulding Marine Center in Sausalito, where I will teach electrical excellence, simplicity, and how not to get electrocuted. They suggest a $50 donation and always provide a great lunch. Starts at 10:00AM; goes to about 2:30. Please RSVP. Link here for registration

Electrical Basics: Bus Bars

Clark October 17th, 2016

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Just twenty or thirty years ago the electrical system on the average sailboat was very simple. It had two batteries connected to an OFF-1-2-BOTH battery switch, and all the loads were fed from there:
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On the back of the battery switch were three studs: one for each battery, and one for the common, that is, the terminal that connects to the alternator and all the loads:

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The battery switch for this Catalina 30 is this way. In addition to the connection to each battery, the battery studs on the back of the switch are good places to connect the outputs for the shore power charger, the voltmeter, and the bilge pump, all things we want permanently connected to a battery, and never turned off.

On the common terminal of course is the big cable connected to the engine’s starter, and the feed wire to the main distribution panel, which in this case is just a 10 gauge wire: ah, the days of such simplicity. The back of this switch might be a little crowded, but all of these wires fit.

Today the electrical system on the average sailboat is more robust and complex. With just the aforementioned connections to the battery terminals – voltmeter, charger, bilge pump, maybe the memory wires from a stereo or other electronics – the studs are already too crowded. On the common terminal, forget it. You might have the big cable to the starter, a big cable to an inverter or inverter/charger, big cable to the windlass, and a good-sized cable to feed the main distribution panel, which now supplies a radar, a refrigerator, and a range of modern comforts.

All these cables simply won’t fit, and according to the ABYC standard, you shouldn’t stack more than four ring terminals on a stud anyway.

Enter the bus bar. Give yourself some breathing room!

A bus bar simply expands your single stud into four or more. A large gauge cable, and nothing else, connects to the common stud on the battery switch. The other end connects to the bus bar, where you’ve got a row of big studs for all the other connections. The same could be done for one of the battery connections if you find you’ve got too many cables and wires that need to be connected directly to a battery, without a switch in between. Generally speaking, we want to keep our battery terminals clean. Manufacturers sometimes dictate otherwise, as with some electrical system monitors and chargers, but we should endeavor to have nothing but the supply cables connected to our batteries.
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The bus bar is even more necessary on the negative side, where the negative cables from the batteries, negative ground from the engine, inverter, windlass, corrosion ground (green wire), and feed to main distribution panel, all must connect. Might also note here that bus bar covers are equally important, as they make for a lot of exposed, live metal:
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Many older boats foresaw this scenario, but it was before off-the-shelf bus bars, so they just added distribution studs, or what Blue Sea Systems now calls a Power Post, but one stud just isn’t enough. These are overcrowded and a bus bar would create more room, make circuits easier to trace, and ahem, that thing about no more than four ring terminals to a stud?:
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Now Blue Sea Systems has gone plum crazy with the PowerBar 1000. It’s the Super Jumbo Extra SuperMax GT version of the bus bar. I have yet to find use for one, but when I do I’ll know I’m serious:
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Remember, good wiring is not only electrically sound, but easy to follow. Wherever you find yourself running out of room and trying to cram too many terminals in a tight space, even if it’s electrically sound, it will be difficult to service and trace in the future. A relatively cheap and simple bus bar is often the solution.

Boat Command CONNECT! Meets Smoke Alarm

Clark August 1st, 2016


The manufacturers of Boat Command, the boat monitoring platform, didn’t build the system with a smoke alarm option. It’s got all manner of sensors, inputs, and alerts, but no smoke alarm, and if you read Boat US’s statistics on boat losses and insurance claims, fire is number five. Stats aside, the main things I worry about while I’m away from my boat are flooding (that’s a big number 1), fire, break-ins, theft, and dead batteries. These are the main reasons I installed the Boat Command system, but it does lots of other neat stuff too. Full disclosure: as a marine electrician I install a lot of these systems, and I’m a dealer for the product.

While neither Boat Command nor the smoke alarm manufacturers make it obvious, it’s a very straightforward to add a smoke alarm to the system. As you can see from the photo above, the right place for a smoke alarm on my boat is about a foot from the Boat Command CONNECT! base station, so running the wires was a snap.

Within the Boat Command platform are several functions that can be renamed and repurposed. One of these is the High Water Alarm, which is just a normally open (NO) relay to ground, designed for the connection of any old float switch: Float is down, circuit is open and no alarm; float goes up, circuit closes and ALARM! via text and/or email, and on the Boat Command dash board. Since Boat Command has “belt and braces” coverage for flooding, via detailed activity monitoring on two bilge pumps AND the high water alarm, I could repurpose my high water alarm as a smoke alarm. On my boat the second bilge pump essentially IS a high water alarm, as in, if it triggers then something is seriously wrong.

Repurposing is very simple: On the drop-down menu on the Boat Command dashboard select Boat Settings/Inputs, where you will see various inputs, all of which can be easily renamed. Just change High Water Alarm to Smoke Alarm and click Save Input Settings:
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Simple enough so far. Now, onto the smoke alarm. The smoke alarm manufacturers don’t advertise it either, but on what is commonly called a “Four-wire smoke alarm,” two of the wires are, guess what?, a normally open (NO) relay, which closes when the alarm is triggered. I think the reason they don’t advertise it is that these smoke alarms are usually part of large networks that connect to a sophisticated central monitoring computer. Think 90 smoke alarms on six floors, all connected to a central panel. They’re not used to selling just one to some dude for a single-unit installation.

The two sides of the relay are two out of the four wires. The other two are for 12 or 24-Volt DC power. This is another great feature: it means that the smoke alarm can be powered from the same terminal strip as the Boat Command base station, the smoke alarm is powered from ship’s power, and you will never have to change batteries or deal with annoying chirping noises.

Here is the base of the smoke alarm, with the + and – terminals being ship’s positive and negative, and the two A terminals being the two sides of the relay. It doesn’t matter which way you connect to the two A’s. I happened to use 4-conductor cable with red, black, yellow, and green wires:

I used this smoke alarm, but again, I’m 98% sure that any four wire smoke alarm will do the same thing. It cost about fifty bucks.

Then I just had to connect the two power wires from the smoke alarm (red and black) to the + and – connections on my Boat Command terminal strip. One side of the relay circuit (the green wire, in my case) also connects to ship’s negative; the other side of the relay (the yellow wire) connects to the orange wire from the Boat Command wiring harness.

I tested it, with real smoke, and yes, a deafening alarm blasted out of the smoke alarm, which was especially blood-curdling within the enclosed confines of my boat, and fourteen seconds later I got a text from Boat Command saying “Smoke Alarm triggered for Condesa.” Now, given that it takes me fifteen minutes to get to my boat from home, it’s hard to say how much good this would do with a real fire, but I’d rather know than not know, and there are people I could reach by phone who are closer than I am.

The Truth About Watermaker Membranes…

Clark June 24th, 2016

…is that they’ve gotten pretty cheap.

In not-too-distant past replacing a single membrane on a small watermaker was a $600-$800 hit. Now, as with so many other things, you can go online and buy a membrane for $150-$220. And it doesn’t matter whether you’re replacing a 20-inch membrane or a 40-inch – the two most common sizes – the price is the same.

Before I go any farther, when a watermaker is performing poorly it is seldom the membrane, but the membrane is the first thing people want to blame. You must first ensure that everything else is within spec before you condemn a membrane. This means that the system must be doing exactly what it’s supposed to do with regard to flows and pressures, and still making crappy water (low quantity or high salinity). Pumps must be pumping the quantity of water they’re supposed to pump, at the right pressures, or water quality and quantity will suffer, even with a perfect membrane.

Membranes don’t just up and fail, or rather, when they do it’s a one in a thousand thing. When they fail they usually decline slowly, over a period of 5-10 years, sometimes longer, or they fail because they were abused (chemical damage, lack of flushing, or lack of pickling…tsk tsk).

Cautionary tale over. $150-$220 for a membrane still isn’t free, especially if you’ve got a system with multiple membranes, but it changes the game somewhat. Say you left your boat in a hurry last season in the Caribbean, and you’re not 100% exactly, positively sure you stored the watermaker properly. You could fly back to the Caribbean armed with various cleaning chemicals, your fingers crossed, and the prospect of buying a membrane anyway, at Caribbean prices, or you could just buy a membrane online, stick it in your baggage, and replace it as a matter of course. Guess work averted.

Likewise with the long term view: At this price you might just replace your membrane(s) after 4-5 years when you suspect they’re fading, and be done with it. An older or fouled membrane can often be brought back among the living by chemical cleaning, but the chemicals can be expensive and the cleaning process can take hours of hands-on time, and soaking overnight, with various buckets and hoses strung about in awkward places.

I don’t mean to encourage gratuitous membrane replacement, filling the worlds landfills with used membranes, but you get the idea. And it’s no sure bet a new membrane will make better water than an older one. There is a lot of variation in membranes, even the exact same part number from the exact same production run, so if you’ve got an older membrane that is still performing well, stick with it. I’ve seen them perform within spec for up to 15 years.

Final caution: new membranes are shipped stored in nasty storage chemicals. The membrane must be flushed for at least 20 minutes to remove the chemicals, or it will be damaged when the system is pressurized. With a new membrane installed, run the system unpressurized for at least 20 minutes before making water.

Final final caution: Membranes don’t have long shelf lives in their packaging. If you’re thinking you’ll just buy a spare membrane to have on hand for a few months or years down the road, this is a bad idea. The membrane will undoubtedly be dead after, say, six months.

Replacing a membrane is quick and straightforward, as long as you’ve got access to the pressure vessel end cap, and room to slide the membrane out. Here is a video on how to do it on a Spectra. The process is similar or identical on other types of pressure vessels. The only thing you really have to remember is to keep the brine seal on the correct side:

New Cooling System on Perkins 4.236

Clark June 16th, 2016

This upgrade is common to all older Perkins diesels (the Perkins 4.108 is probably the most common Perkins found on boats). Bowman, the company that made the marinizing equipment for Perkins, has re-engineered things over the years, so that instead of having a combination header tank and heat exchanger on one part of the engine, and a water jacketed exhaust on another, they combine it all into a combination header tank/heat exchanger/exhaust manifold.

These engines were originally fitted with oil coolers. Now in some cases they say you can do away with the oil cooler unless your engine is run very hard. Since mine chugs away at about 1400 RPM cruising speed, I did away with the oil cooler.

At 50 years old, my old header tank was disintegrating (one surveyor took a very dim view of this), as was the heat exchanger stack, so that the whole business relied on a lot of polysulfide sealant and JB Weld. The old oil cooler failed spectacularly about five years ago, both blasting hot oil all around the engine room and filling the crank case with sea water. This is why one should always carry several oil change’s worth of oil at all times.

The first hurdle, and the only real engineering/fabrication part of the job is to modify the intake. If you look at the picture above, at the top of the picture you’ll see the air intake duct sticking out over the exhaust manifold. This would not do, as the new part would attach right there. The intake duct must be cut off and moved somewhere else. There are several ways to skin a cat, but I decided I wanted to keep my intake duct right in the middle, the way Perkins engineered it, but sticking up instead of out to one side.

I went off to my normal machinist/metal fabricator guy, to find a sign in his window saying he wasn’t taking any new work and would be closing up shop. I tried another place nearby, stood in the middle of his shop leaving him a voice mail, and never heard back. Found another metal fabrication place that was backed up four months. Left it at one place: They said they’d get it done the next week, didn’t, didn’t even bother to call me, then took off on vacation. I want back ready for battle, found the doors wide open, nobody home, and my parts sitting right where I’d left them two weeks before. I took my parts and my card and took my business across town. Is this telling me something? Should I be learning to weld? Is it just a Bay Area thing, or is it getting hard to find good tradesmen in this world?

At the second or third stage in this frustration I decided I’d go at it alone as much as I could, leaving only the welding to be done by a pro. The first step was to cut off the intake duct with a hack saw, which was satisfying and straightforward:

Then I went to www.onlinemetals.com and ordered a few pieces of stock, some aluminum tube to make the new duct, and some aluminum plate to cover the hole where the old duct had been. I used a 2-1/4-inch hole saw to drill down into the intake, making a home for the new duct. After a fair amount of cutting, sawing, and filing I had my pieces finished and ready for the welder:




Here are the old, tired bits that went away:

On top is the old exhaust manifold, which broke when I removed it. It was raw water cooled. The exhaust manifold on the new bit is fresh water cooled. Methinks this is a change for the better.

Here is the new bit, painted and ready for action:


There were many other little bits and bobs to source, customize, and fit. I had a brand new spare water pump, so I installed that while I was at it, replaced the transmission cooler for the same reasons as the heat exchanger, repainted where I could, and replaced all the engine hoses, as they were getting on twenty years. And I got one of those K and N washable air filters, since that’s what all the kids seem to be getting these days:


So far very happy with the modification. It did away with about fifty pounds of ancillary crap on the engine. Seriously, I’ve got a giant box of stuff, which I can barely lift, which is no longer needed, and this doesn’t even include the old header tank or exhaust manifold. And I’ve now got about another foot of space between the front side of the engine and the engine room bulkhead, which is great because the core of my electrical system is on this bulkhead.

The only problem is that she seems to run too cool. My wife asked, “Isn’t that good? You installed a new cooling system and now it runs really cool?” Excellent logic, but not exactly right. There’s a right temperature, which for Perkins is something like 160-180F on the cooling water. Mine seems to be barely tipping the gauge at about 120F. So now it’s off on a bay cruise with digital thermometer in hand to figure out if it’s an instrumentation problem or if she’s really running cool. Yes, I bought a new thermostat in case that’s all it is.

The Future Is Here: Bottom Cleaning Nanobots

Clark April 1st, 2016

With copper-based antifouling paints just being banned in Washington state, the writing is on the wall. We’re going to have to figure out an an environmentally-friendly way to keep the critters from growing on the bottoms of our boats. That’s where BottomBot comes in.

Dan Stein, BottomBot’s CEO says, “We took our technology from the medical industry, where nanobots have long been in development. There is a family of nanobots designed to be released in the blood stream to remove plaque from the insides of your arteries. These nanobots aren’t quite ready for prime time in medicine, for safety reasons, but the bottom of a boat is much less sensitive than say, your aorta.”

BottomBot’s first product in in beta testing on 25 boats in the Pacific Northwest. Sam Stanton, a beta tester, says, “It’s like having a bunch of little pets. I can’t see them of course, but sometimes at night I think I can hear them. It’s not perfect yet – some parts of my bottom stay cleaner than others – but my boat hasn’t had any antifoul on in for eight months, and these are quite fertile waters, and the nanobots seem to remove all the growth.”

The base product for a 40-foot sail or power boat includes 2000 nanobots and a charging station. The charging station looks like a scoop for a thru-hull, and each nanobot must make its way back to the charging station once a day, where its tiny battery gets magnetically recharged.

“Our biggest hurdle was getting them to stick to the bottom.” says Stein “It was fine while the boat was sitting the the berth, but once a boat hit 8 knots a lot of the bots washed off, and this got expensive. We experimented with a ferrous bottom coating, so the bots could attach magnetically, but this just exchanged one metal-based bottom coating for another, and introduced corrosion issues. We ended up with a patented design where the nanobot is shaped like a limpet, and moving water actually helps it stick to the bottom at high speed. Still, a few get lost, and some fail, every week, so every year or two you’ll need to replace a couple hundred bots to retain good cleaning ability on your entire hull.”

Each bot has simple directional programming that sends it out over the bottom in random direction. “It works kind of like a bunch of Roombas,” says Stein, “Then each bot has a tiny scraper, and just removes anything softer than epoxy as it moves along.”

Initial pricing is expected to be over $15,000 for a 40-foot boat, but the prices are expected to come down. “When you consider that this gets you out of doing bottom jobs forever, it eventually pays for itself,” said one of the beta testers.

“The boat’s bottom ends up free of marine growth, but eventually there is this accumulation of grey goo.”

Global Ship Traffic Via Satellite and Terrestrial AIS

Clark March 4th, 2016

What chance does a humble cruising boat have out there? Not a lot of places where it’s safe to sleep on watch.

Human Arm Found Floating At Olympic Sailing Venue

Clark February 26th, 2016

I’ve have tended to downplay all the press about the filth in Guanabara Bay, the 2016 Olympic sailing venue. I spent a few months living aboard there, and it’s on par with many large ports around the world. Finding a dead dog wouldn’t be out of the ordinary many places in the world, especially in a tropical place where the tends to be lots of flotsam and jetsam. But this kind of takes the cake. I won’t post the photo, in case you don’t want to see such a photo, but the photo is at the end of the story, here.

Happy sailing!

Tough French Cruiser Shot, Stabbed, Bashed, and Robbed off St. Croix

Clark February 22nd, 2016

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The whole story is here. Either local law enforcement completely bungled this case, or the victim’s story doesn’t add up. What is a matter of fact, because there were witnesses, is that this guy, at age 70, limped his boat back into port with his femur shattered by a gunshot wound, came alongside a tugboat, then proceeded to throw winch handles and sundry objects at the side of said tugboat for 45 minutes before somebody took notice. Shiver me timbers.

After Twenty Years, Naval Academy Brings Back Celestial Navigation

Clark February 18th, 2016

After removing it from their standard curriculum for nearly two decades, the navy has decided that the threat of cyberterrorism, electrical pulse attacks, lightening strikes, and other potential blackouts of the GPS system warrant reinstating the age-old art. The US Coast Guard, which stripped it from their curriculum a decade ago, is following suit.

Should cruisers be taking a hint?

You can read about it in the Capital Gazette or The Washington Post

The GPS system has never been “brought down,” according to the government, but local disturbances and drop-outs are commonplace. And it’s conceivable that the system might be brought down intentionally by the good guys so the bad guys can’t use it. My mole in the commercial shipping world says they have to be up on their celestial for any trip to the Persian Gulf, for just these reasons.

My first time cruising, in the eighties, our whole trip across the Pacific was by sextant, but I wasn’t doing the navigating. Since then I’ve always carried a sextant with the tables and a nautical almanac, and I’ve occasionally taken a few sights, just to convince myself that, in a pinch, I might, sort of, probably, eventually, be able to figure out where the hell I was, more or less.

Maybe it’s time to get more serious about it? If nothing else, it might be fun.

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