The Truth About Watermaker Membranes…

Clark June 24th, 2016

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…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

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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:
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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:
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Here are the old, tired bits that went away:
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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:

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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:

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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

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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.”
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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.

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“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

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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.

Land Yachting Through Patagonia

Clark February 12th, 2016

Land-Sailor from Land Sailor on Vimeo.

Gotta hand it to these guys: http://land-sailor.com/the-project-en/

That Sinking Feeling off the Baja Coast

Clark February 3rd, 2016

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It was 1991, and we were three fools fresh out of San Diego State. Brian had bought an old Catalina 30, and we spent six months fitting her out. Against my protests, Brian changed her name to Break‘n Wind, a boat name I’ve encountered several times over the years, and never liked any better.

Brian’s artist buddy painted the new name and hailing port on the transom, along with some sorry-ass blue palm trees. I asked the artist, “Isn’t break spelled B-R-E-A-K?” He’d spelled it Brake’n Wind. The paint had already semi-dried, so we ended up with one E wedged in there somehow, and another E rubbed out with acetone, and it never looked quite right.
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The overfilled cockpit, with fresh flowers from our bon voyage party.

We finally set sail and ran down the Baja coast at night, the boat laden with windsurfers, surfboards, a guitar, scuba gear, and enough food to transit the Northwest Passage. Tim, the third crewmember, was on watch in the cockpit while Brian and I tried to sleep on opposite sides of the main salon.

I was drifting in and out of sleep when the automatic bilge pump light caught my eye. It went out and I closed my eyes again, but ten seconds later the light came on a second time. When it lit the third time I nudged Brian, “Hey, the bilge pump has gone off three times.”

Brian flipped out of his bunk, turned on the lights, and ripped up the little floorboard in the middle of the main salon. Water poured into the bilge from somewhere aft. We opened the engine compartment, where a stream of sea water flowed past the engine mounts.

“She’s taking on water!” Brian yelled.
“What!” Tim peered down the companionway, wide-eyed.

We cleared out the quarter berth to get access to the packing gland, and Brian squirmed in with a flashlight.

“It’s coming from farther aft, and it’s a lot of water now! It must be the rudder!”

We were a good fifty miles off shore, following Captain John Rains’s advice to sail well outside the shipping lanes. Panic.

We tore open the cockpit lazarettes and scattered ridiculous piles of junk on deck: scuba tanks, fins, masks, wetsuits, spears, beach chairs, a barbeque, windsurfer sails, oars, and awnings. It was the adventure of a lifetime and, well, we’d overpacked. Occasionally the beam of the flashlight met the spooked eyes of a shipmate, and around us were only blackness and a cold winter westerly. We avoided eye contact as we moved the life preservers, the ditch bag, and the EPIRB.

The automatic bilge pump ran nonstop.

We emptied the aft lazarette, which gave us access to the rudder stock. In the aft lazarette we could also see the bilge pump’s thru-hull. Next to the thru-hull, unattached, lay the bilge pump hose, with water spewing out of it, into the lazarette.

“We’re saved!”

We slid the hose back on the fitting with a new hose clamp, and the bilge pump pumped the same load of bilge water for the last time.

Bug-eyed with the adrenaline of our first mid-ocean crisis, the voyage began in earnest, and our little ship seemed more plucky and devious. At our bon voyage party a friend had given us a bottle of single malt scotch that was much too good for a couple of twenty-one year olds. We took slugs out of the bottle and talked about near misses, what ifs, what-to-dos, and all the adventures we were about to have in Mexico.

Brian and Tim drifted off as I started the 3 a.m. watch, with my first sunrise of the voyage to follow.
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Break’n Wind under sail

Knowing Your Boat: The thing nobody ever talks about

Clark January 21st, 2016

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“Uh, how is the boat going to behave when that thing hits us?”

Contrary to all the focus on new boats, their features, and their performance, the captain’s knowledge and intimacy with said boat is probably more important. In fact, when it comes to heavy weather sailing, what resides in the captain’s head is probably the most important piece of safety gear aboard. What some might call “getting to know your boat” may accurately be called the most intimate relationship a human being can have with an inanimate object.

The Cliff Notes version of getting to know a boat is a shakedown cruise. You’ll learn more in a few days knocking around out there than in months at the dock, and usually come back for a whole round of repairs and improvements you never knew you needed before the shakedown. Long distance racers cram and rush this process, in as many types of weather as possible, usually with a very expensive RIB full of cameras and coaches chasing them around.

Joshua Slocum’s relationship with Spray is legendary, of course: the way he got her to sail herself and hold a course, most of the way around the world. On the flip side was Sir Francis Chichester’s Gipsy Moth IV, which was actually a very tender and squirrelly boat, as Charlie Doane pointed out. But at least Sir Francis figured it out, and knew not to push her too hard.

True familiarity with a vessel is a long process, necessitated by the time it takes to encounter all kinds of weather and all kinds of situations.

For me and my boat, this has been an eighteen year process, and it’s still a work in progress. A year or two into my circumnavigation I had occasion to sail under jib and jigger: My boat is a ketch, and dropping the mainsail completely and sailing under just a jib and the mizzen creates a reduced, balanced sail plan in high winds.

It wasn’t until many years into my circumnavigation that I confirmed what the old owner told me, that she ran beautifully under bare poles, with the windvane set a few degrees off of dead downwind.

And it wasn’t until we were caught in relentless Pomperos off the Patagonian coast that we confirmed that she heaves to perfectly under her mizzen alone. “Parking the car,” we came to call it, with a trail of slick water left to windward, killing the breaking seas. Here is a video, doing just that, with Commerson’s dolphins enjoying the ride. Note how calm it is right next to the boat, and it’s probably blowing thirty:

I have yet to deploy the sea anchor. I bought a very sturdy custom-made sea anchor in New Zealand, and I’ve got it fitted out with various rope, chain, a trip line, float, and chafe protection. I’ve gone as far as connecting it to the bow and running the tackle down the windward side of the boat with zipties, for easy deployment. The one time I was on the verge of deploying it, in the Arabian Sea in a tropical storm, I was worried about the current, which might have put us crossways with the wind, and made matters worse. Instead we ran under bare poles, which ended up putting us a couple hundred miles downwind and down current, but at least we didn’t get knocked down.

Someday I might have occasion to deploy the sea anchor, and I may discover she lies to it beautifully, or I may learn that she tries to sail off at oblique angles like a roped calf.

After all this time getting to know my boat I know she is “seakindly.” This is why I wouldn’t think of replacing my fifty-year-old boat that I’ve owned for eighteen: If I got a new boat I’d have to figure all that stuff out all over again, and when bad weather came I wouldn’t have that same warm fuzzy feeling I have with Condesa, knowing she’ll bob over it like a duck. I guess if I hadn’t come to know her as seakindly, I might be more open to getting another boat. Plus my familiarity with all of her machinery and systems is another well of knowledge I’d have to learn anew with a new boat.

Yes, delivery skippers, racers, and new owners often put to sea in new and untested boats…and a lot of bad things happen under these circumstances. A well known and well understood boat is a safe boat.

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