Quiet

Tying up a halyard so it doesn't slap.

Sail Trim Rant

My blog, my opinions. Some I can support, but I don't need to. I love a good rant.

When I started my career 30 years ago, my supervisor was a hard working man with only a few business classes. He did very well for himself, using hustle and dependable common sense to drive our business to more dependable success than our generally better educated and better financed competitors. After assigning a particularly thankless job to a laborer or contractor, or after watching some failure of common sense, he often proclaimed that he was "glad he paid attention in school." In fact he was very well educated by the school of careful observation. The primary reason I can pass practically every sailboat I meet--there aren't too many racers in the area, but there are certainly many much larger cruising boats--is because I pay attention. To me, that art and science of converting wind into motion is much or what makes sailing worthwhile.

My rules of boat speed.

Sail Trim

1.  Don't over sheet reaching. The most common fault on a reach, is for everything, more or less, to be sheeted in. Embarrassing proof to everyone that you don't know how to sail.
2. Don't over sheet to the weather. While a racing monohull with good foils and flat sails--the kind of guy that writes manuals on sail trim--will carry the traveler above the center line and boom on the center line, that doesn't mean the is correct for a cruising boat. You're going to have to experiment, pacing other boats, but cracked-off just a hair is generally faster for boats with more drag and lesser foils. The more you can sheet out, the more drive is forward.
3. Twist. There is never a reason that main should not twist to match the wind; less hard on the wind, more off the wind. By proper application of traveler and vane, lead and barber hauler, working sails can always be twisted to match. Wind speed, and thus direction, on deck and aloft are different.
4. Barberhaulers and outside tracks. Add the hardware that is needed, for other wise 1/2 of your sail area is wasted through improper trim. Look at other boats and don't be afraid to drill holes.
5. Flogging sails. The wind came up a little, so they luff the sails to reduce power. Oh dear. Reef!
6. One-sail in a blow. This isn't seamanship, this is laziness, and it results in shortened sail life. Often the sail is pressed far beyond its recommended wind range, because the force is not spread across 2 reduced sails. Instead of stowing one sail, reduced both; the result is faster and better balanced. Jib-only can also endanger the rig in some boats (mast support improper), and forestay tension (luff sag) generally suffers (on many boats mainsheet tension is a major contributor to forestay tension).
7. Do NOT keep the topping lift so tight the sail never takes the load. Leach stretch is NOT reduced by keeping the topping lift on; this is pure urban legend. It can, however, be made worse, since when reaching the load is not carried across a taught sail but just on the leach and battens. Other sailors see the tight lift and snicker. (Very light winds can be an exception, when the lift can support the boom and allow twist, but most cruisers are motoring then).

Clean Bottom

1. Best paint. Given what you pay for the boat, slippage, and hauling, bargain shopping for paint is pound foolish. For multi-season soft paint, I've tried many and like Micron 66 best; you do need ~ 7500 ppm salinity for it to stay on, making Deale about the northern limit in the BAY. I have no experience with hard paints or single-season paints. If it says West Marine on the label, you've made a mistake.
2. Don't buy a low VOC paint because you think you have too. If it doesn't last longer and save fuel, it is not environmentally better, not over a full life cycle.
3. Swim. You are going to have to clean the bottom, at least occasionally. If you aren't comfortable in the water I can't imagine why you took up sailing. I'm sure there are good reasons, I just can't imagine them. If the water is cold, get a wet suit for emergencies (rope around prop, hull damage, MOB, anchor stuck, some groundings). Take it easy on soft paints; frequent sailing is better than cleanings.
4. Use it up (soft paints). Toward the end of the paint's useful life, give it a scrub or 2. This will minimize the need for sanding and improve bonding. Try to scrub in an area with a good tidal flush and few sensitive receptors; the harbor is not the best place, a river-mouth sand bar is probably better, depending on local geography, of course. If it seems like hard work, think of it as good exercise.

 Loose the Weight

1. Go through the cabinets every spring. Never know what you will find, perhaps something that's gone missing.
2. Spares. Are you really going to fix that item while on cruise, or would you wait until you are home? Then take it home. To much junk at home already? Pitch some. Stop buying stuff.
3. Calculate the cost of carrying junk. It will embarrass you.
4. Think of weight with every new project. Can it be lighter? Is it worth the weight, windage and complication?

 Good Sails. Obviously important going to the weather (doesn't really matter off the wind), but if you can't afford or justify new canvass...

1. Downhaul hard. This will help move the draft forward by stretching the luff.
2. Flatten with outhaul. I've met sailors that didn't know it was adjustable. Just pitiful.
3. Flatten the genoa with an outboard lead (barber hauler or traveler). This will reduce twist a bit, but the reduction in draft is generally worth it up-wind.
4. Recut. Sometimes tightening just one or two seams will work wonders. Read up on sail making and/or ask a sailmaker. Stiffer battens can help and increasing batten tension supports the luff. Sailmaking is not a black art, and every sailor should understand how design relates to sailing.
5. Reef earlier. Stretched sails have more draft and thus more power. Reefing also can help flatten sails, but that is variable.
6. Take your lunch to the office in a bag. Soon you will save enough for new sails.

Practice

1. Pace other boats. There is no substitute for measuring your speed against another boat on the same course; variables of sea state and wind even out.  Is your speed less or about the same? Good. Now start pulling strings--more twist or less, tighter and looser--until you start going faster. It's not a race, just the best way of seeing what is better and what is not. I'd been sailing fast cats for years and I had to adjust my sail trim quite a bit for the PDQ.
2. Build a speed polar. Perhaps this is overkill for most, but how do you know what is good for the conditions? Write it down, when you think you've got the trim just right. Compare with next time.
3. Watch course over ground (GPS) more than compass; you may be going more sideways than you think. For areas with strong tides, this is much more complicated. Hope you remember trig and physics.

Engine. No I will NOT suggest power is the best way to windward. A car is much faster.

1. Use the fuel. You might as well use at least one tank each year. Whether gas or diesel, whether you use a stabilizer or not, it needs changed, just like the oil. Since most engines die from dis-use rather than use, the hours to burn one tank annually is actually a contribution to good maintenance.
2. When the wind is just a little too noserly to sail with many tacks and you really have somewhere to be, motor straight to windward, then sail when the angle is better or the wind has come up (afternoons are often better). You might just get a little more sailing in that way. Boy will it seem quiet.
3. Read a book. Makes motoring more fun.

Fear of Spinnakers

1. If you don't fly the chute, when the conditions are reasonable, you just aren't a sailor. Sorry, it's part of the art. Kind of like skiers that stay on the greens. Why bother.
2. If the sail is hard to fly, perhaps the rigging is wrong. Spinnakers vary in design and fullness, so what is best for one may be quite wrong for another. Try many wind angles and rigs until you find what she likes.
3. Learn both inside and outside jibes. Read up.
4. Don't sail with one sheet (lower to jibe). That's lame.

Boats with better trim go faster with less heel, are lighter on the tiller, track straighter, and handle better and more safely when things kick up. Learning to sail a boat to the limits of its capabilities is key when lee shores and capsize threaten. A faster sailor can be a safer sailor.

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I don't always care about speed. Some days I'll just drift around, not much caring. That's good too.

I Have No Words....

There is a large bay window in the side of the building to facilitate viewing. It's a small town, so perhaps folks "drive through" just to see if it's someone they know.

... but can I get a chocolate shake while I'm in line?

Nine Days of Family Fun

8-8-2014
Deale, MD to Slaughter Creek.

My favorite wetland kayaking destination, this trip the goal was to introduce my wife to the quiet maze that is The Broads of Slaughter Creek. Part of the Taylor's Island Wildlife Refuge, it combines with the Blackwater refuge to form one of the largest natural areas on the east coast, and certainly one of the largest contiguous marshes. I've posted more on the area here.

James Island, leaving Slaughter Creek. Numerous immature eagles roosting.

We used the tender to tow our kayaks deep into the maze. My wife was first to spot the circling bald eagles (3 at one sighting!) and later, a periwinkle fight (sort of like Battleship, waged over the top of a small humacks from kayaks) between me and my daughter. I think the bald eagles were the highlight.

A quiet night on the hook. I've come to like the Mantus chain hook; the new plastic keeper makes it a fast one-hand operation with absolute security. In fact, I'm still using the 3-D printed prototype Mantus sent me for testing.



8-9-2014
Slaughter Creek to Smith Island

Fishing. After several hours of unproductive trolling, I caught a nice snapper blue while I was reeling in. A nice surprise. A bit of a jolt when you are sure that you are winding in slack line... but then again, that has happened to me several times; I'm reeling in, done fishing, only to get smacked by a 20-pound rockfish when I least expect it.

Not a trophy, but in truth, the small ones taste best. Perfect size for the pan.

Eating. The highlight of Smith Island may be the crab cakes at Ruke's. No exaggeration, and without any reservation, they are the finest anywhere, including 5-star restaurants. They simply melt in your mouth, exploding with flavor. Wish I knew the secret, though I suspect minimal filler (they tend to fall apart) and very fresh crabs are key. Worth the trip, just for that.

 Not fancy, and a bit run-down on the outside, but oh my....

Kayaking. You could spend a week exploring the Smith Island complex and never see most of it. We spent 2 nights and enjoyed as what as we could, paddling different areas than those we have explored before. Swan island is nice, just north of the western entrance channel. There is also a dredge spoil island on the south side of the western entrance that is home to thousands of gulls. Goat island --just across the harbor--is filled with feral goats.

Goat Island. There are perhaps 40 on the island, always climbing trees, for instinctual reasons, we suppose.

Can't let a jetty stop you. Up and over.

 

Impossibly low freeboard on the flats boats. Much of the crabbing and clamming water is very thin.

 They say you should name the boat for your daughter rather than your wife, since the former is a permanent relationship, the later less certain. I'm guessing this was named for the daughter.

Found this on the beach. After a little research we determined it is a Loggerhead sea turtle rib. Though I've never seen a live one in Chesapeake or nearby coastal waters, we've found eggs and carapaces. They are threatened, but not truly rare.

8-11-2014
Smith Island to Tangier Island.

Tacks included, perhaps 20 miles of bashing into steep chop and 20 knots winds. Tacking though 100 degrees, boat speed cycled between 8.5 knots on the flat bits and 5 knots when the beam buried in a steep set, sending green water all the way to the cockpit, averaging 6.7 knots dock-to-dock, including time spent untangling a crab pot from the rudder--hard to see those buggers in the conditions.

More fishing. I think the cats got most of the minnows.

One of our favorite places for just doing nothing, we still manage to keep busy.

• The fishing off the dock is reasonable. A flounder, several sea bass, and some spot.
• Crabbing. This time we focused on soft shells; harder to find, but more eating per crab. I'm not convinced they are as sweat, though.
• Swimming. The nicest swimming beach on the Bay is the hook.
• The Homecoming. Each summer they have a festival where family from all over returns to the island. Only inflatable "rides" (they've got to come by boat) but good music and good food.
•  Local dining. The Fishermans' Corner is very good, and Four Brothers has a mean crab melt.

The claws aren't much of the threat when they're soft.

The Homecoming Festival sets up on the airport flight line, a short walk from the marina. The whole town is there, often more than 200 golf carts! Sure, as a visitor you are not a part of the family, but that doesn't matter. $5 admission and good music.

 8-17-2014
Tangier to Solmons Island.

Uneventful light air sailing. Caught 2 more snapper blues on the way, which added to the interest.

The Tiki Bar is the local muscle boat hang-out, worth a few minutes just for the people watching and the music. Anchor further away, though, up mill creek. Be aware of the cable area.

8-18-2014
Solomons Island to Deale

More uneventful light air sailing. An hour was spent on the beach at Calvert Cliffs, collecting fossils and enjoying the quiet, before the hikers reach the beach.

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Most of the meat in the fridge returned home with us; out catch matched our appetite, and some fish were distributed to my parents. We went out for steak that first night home, having reached our fill of seafood, at least for a time.

Eco-Trash

(I borrowed some of this from Windborne. It seemed important to share.)

I'm all about eco. I work for one of the largest recyclers, have built multiple re-cycling and recovery plants, and have invented new processes. But I'm not in favor of mis-labling or eco products that don't meet specifications or perform.

This is NOT mineral spirits.

 This is an emulsion blended to comply with west coast VOC rules. What it is good for, I have no idea.

If it were mineral spirits, it would comply with ASTM D235 (the defacto definition of the term), which it does not in many ways. Basically, FALSE LABELING.

Kleen Strip does make mineral spirits. They also make odorless mineral spirits, though plain or rule 66 mineral spirits are better solvents (the KB value of odorless MS, a measure of grease solvency, is only half that of regular and rule 66 solvents, which matches my experience). All of these meet ASTM specifications and can be used to thin paint and clean-up petrol based caulks and paints.
            
                                  

 ASTM D235, Type C, class C

* Petroleum-based.

* Clear, nearly water white (25 units is very nearly perfectly clear).

* Does not contain water (300F initial boiling point).

Why Does My Anchor Come up Backwards?

After fixing this on 3 boats (mine was the first) I thought I would share something so obvious it is commonly overlooked. It's embarrassing to even explain it.

 There are many things that can twist the anchor, not the least of which is a shift in the wind. The easy, or at least obvious solution, is a swivel, but failures are not unusual; my SS swivel had a nice interior crack that I only noticed when I took it apart to replace the anchor. Many sailors have abandoned swivels for this reason, and then wondered if they made a mistake when the anchor came up reversed most of the time. Never fear.

Notice the nice straight chain. No twist.

When connecting the anchor, observe that there are 4 rotation options. Unless you considered this at the time, you had only 1 chance in 4 of getting it right.

• If you are 180 degrees out of alignment, reattach the shackle, inverted.
• If you are 90 degrees out of alignment, either add a shackle or trim one link.

The chain cannot rotate in the gypsy, thus, getting the twist right significantly improves the odds of the anchor coming up right way round, more so if the windlass is near the roller. Not 100% certain, but it will greatly improve the odds.

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One other thing that helps. for that last half turn; go very slowly astern while pulling it up the last few feet. The speed of drift may be enough. Most modern anchor will naturally rotate to  face the current at just a fraction of a knot. Handy, since the boat will start to slide back as soon as the anchor clears the bottom anyway.

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Why would you add an extra shackle? Because with G43 and higher chain, the size that will fit the anchor well and the size that will fit the chain may not be the same. Place the larger shackle with the bow in the slot (the attachment slot is designed to clear the pin bosses) and the smaller shackle with the pin (largest that will fit) through the last link. Nice and flexible, minimal side loading of shackles, which they hate.

Use It Up, Wear It Out, Make It Do, or Do Without

I think these are done. West Marine, don't last too well, but I like the fit best and I have tried many.

From later that evening; un-named cove, far up Harris Creek. Even on July 5th, a narrow and unmarked entrance keeps this place private.

Sharp's Island Light. The winter ice pushed it many years ago. It is no longer an active ATN.

Just a nice over-night cruise, me and the wife. A nice breeze and no unpleasant surprises... other than forgetting to fill the tender gas tank. But we weren't far. And no jellyfish yet, not where I've been, the up-side of a brutal winter.

Catamaran Slip for Cheap in Deale

 

Why catamaran? There's only about 5' of water and about 3.5 at extreme low tide (soft mud bottom). But there is room for 16' beam.

The previous boat was a Gemini.

Phipps Marina
Calvin Phipps
615 Phipps Road
Deale, MD 20751

410-867-0299

An earlier post has additional detail.

Drinking Water Filtration--The Short Version

rev. 6-21-2014 

(The LONG version was published in Practical Sailor in 4 parts in Spring 2015.)

The Problem. Marina water is basically untrustworthy. Either the well is brackish of the hoses are contaminated with algae growth. Either way, the water contains dirt and too much sulfur for pleasant consumption. In the midst of researching a 3-part article on water treatment and filtration for sailors I decided to apply what I'd learned to a simple up grade for Shoal Survivor. I'll explain a little--if you want the really long version,subscribe to Practical Sailor.

The Solution. The way I see it, there are 4 parts to the clean water quest:

Step 1. Filter the incoming water. Skip this step, even with potable water, and you will build solids in your tank. Pipe scale will shed, harmless bio-films in distribution piping will shed, and dockside hoses always grow algae. Build up solids on the tank floor, and disinfectants and the residual chlorine in the tap water can't reach the bugs underneath. Given time, biomass is food for bugs, the tank will be come gross. I've even seen lines plugged. My choice? First, run the water for a few minutes to run the junk out of the hose, perhaps rinsing off the dodger; it needs it anyway. After that, I like the Camco RV filters which simply screw on the end of the hose, $10 from Walmart. The marine store stuff is the same for 2-3 times the price. I put a 4-inch PVC pipe extension on the outlet so that it stands easily in the fill pipe.

What about the fact that the carbon filter will remove the beneficial chlorine residual? Opinions vary, but ...

• We've used these for 10 years and never built any biomass in the tank. If the tank stays clean and the carbon removes most organic material, there isn't much for the bugs to eat.
• The chlorine residual is not going to last more than 24 hours, and finally...

 ... Testing (mine and others) confirms that hose end filters only remove about 10-20 % of the chlorine anyway. The flow rates are simply too great to give the residence time needed for effective removal. Honest, it's a marketing hoax, but we're conditioned to buy carbon. A brief review of the certification documents will show that they are only required to remove 25% of the chlorine to claim "removal,", and the test was run at a greatly reduced flow rate. Get some aquarium test tapes and run your own tests. You'll be stunned.

A much better solution is a 1 micron Baja water filter, featured in Practical Sailor. My invention, you're going to love it. Perfect for tap water, rainwater, and jerry can water.

(And don't EVER put glycol in your tank to winterize. It will ferment, it will smell, and there is more than enough food to clog lines. Empty the tank and dry it. the glycol goes ONLY in the pipes. In the pipes it must be installed at sufficient concentration to serve as a biostat (pH >9, and >25% glycol). If the winterizing solution pH is less than 9, add a touch of borax to bring it up. the result will be an effective sterilizing solution and little or not need for spring cleaning.

Step 2. Disinfect the tank.  About 1 teaspoon per 50 gallons is enough to refresh the residual for good water. Better yet, try Aqua Mega Tabs; really convenient and because they are based on dichlorisocyanurinate, the chlorine residual lasts weeks instead of days, keeping the thank fresh. Tip: use 1/4 to 1/2 the recommended dose, as they are rather conservative. Use aquarium test tapes to test for residual (0.1-1.0 ppm).

Bugs that crawled into the venter filter in a single season.

Step 3. Secure the tank vent. Plumbing codes required a 16-mesh screen and a down turn protected from dust, but many boat builders just leave an open pipe--PDQ did. If you look closely, every so often there will be stink bug doing the back stroke or the bones of some no-see-ums on the floor, decomposing. And while your about it, make certain that seawater can't find its way in. Secure the vent.



Step 4. Filter the water prior to the tap. Even if you have followed all of the forgoing, something could have gotten past and the bleach will dissipate in a few days.

Just how big are microbes we are trying to exclude?

Organisms

Size range (microns)

Example (size in mcrons)

Cysts (NSF 53 filters                                     4-14                                     Cryptosporimium  (4-8)

Prokaryotes

Bacterium: typical rod

1.0-0.5 x 1.0-10

Pseudomonas aeruginosa (1.5 x 0.5)

Bacterium: typical sphere

1.0

Bacillus megaterium (7.6 x 2.4)

Eukaryotes

Fungi: filamentous Red Tide

8-15 x 4-8 5-75

Mucor hiemalis (8 diameter) (disolved toxins may be present in red tide)

Fungi: yeast cell

Saccharomyces cerevisiae (29-49.1 μm3)

Alga

28-32 x 8-12

Chlamydomonas

Viruses (NSF P231 filters)

Virus

0.015 x 0.3

Poliovirus (0.03 x 0.03)

Tobacco mosaic (0.02 x 0.3)

While cysts, fungi, algae and some bacterium can be filtered out with 0.5 micron mechanical filters, viruses require either adsorption mechanisms which are hard to define and fade as the cartridge is spent, or membrane filtration (RO through ultra filter). Several carbon block filters have been upgraded with a membrane on the inside, achieving NSF P231 approval (microbial barrier, tested with real bugs to block everything).

How are nominal and absolute filtration performance defined? There is no agreed upon standard, but generally speaking, nominal filtration requires 70-98% retention and absolute filtration requires >98% retention of inert test particles.

I could install UV sterilizers (too much power) or an RO system (they waste about 4 gallons for every gallon produced and they leak bacteria anyway), but I'm not nearly that paranoid. I've had no filter on the boat for many years, and I drank out of some real mud puddles in my backpacking days without ill effect.

I could install the Seagull filter($600-$1000 for a filter--they are completely out of touch with the market) or the equally effective Microguard by Pentek ($129 complete), or better yet, the Pentek DVG-50 (NSF P 231 certified, $131 complete), which are based upon less expensive standardized parts. Both are well tested and rated to remove cysts, bacteria, and viruses. The Seagull filter just costs more. But US coastal sailors don't need either.

My choice? In the US, water treatment and on-boat chlorination are very effective on bacteria and viruses. However, some protezoa and cysts can sneak by, resisting chlorine treatment. These are all we really need to remove at the tap. I like carbon block filters, available in 0.5 micron nominal filtration (Pentek  Slimline or G3 housing with 2x10 CBC-10 or Floplus 10) . They will easily stop of protozoa and cysts (NSF 53 certified filters are rated for this), >98% of the bacteria, and >90% of the viruses. True, viruses are smaller than 0.5 microns, but many are attracted to the carbon surface by electrostatic forces, just as other chemicals are adsorbed. Many bacteria and viruses are attached to larger particles and are removed in that way. Although removals vary according the referenced data source, by the combined mechanisms the reduction is still material. WHO has documented 98.5% reduction of bacteria and 88% reduction or viruses by simple sand filters--a depth filter with similar mechanisms and much larger pore size**.  Granted, it may only take one organism to infect you--I'd worry about that traveling in some areas--but not in the US. This little miracle is only $25 including the housing and replacement cartridges are available through many sources. The time to install? About 15 minutes.

We later switched to a 10-inch filter to get more flow--the Pentek CBC-5 in the photo was OK for drinking, but slow when filling pots and washing dishes. We switched to the Pentek Floplus-10, which is NSF 53 certified for cyst removal and does not restrict flow. The longer housing hangs closer to the floor, but only about 1-inch is required for removal, which can be done without spilling a drop.

(A note to PDQ Altair owners: that big grey carbon-reinforced beam crossing the forward end of the salon bench is the mast compression beam. Do not drill holes in the flange.)

 This universal housing in the photo is from Pentek (158203) was $11, the 0.5 micron carbon block cartridge (2 x 5 standard, Pentek CBC-5) was $10, and the fittings were left behind in a bag by the previous owner. It does reduce the flow at 30-40 psi (standard for boats) from a thunderous 4 gpm that splashed all over, to a somewhat slow 0.7 gpm, about like the refrigerator dispenser at home. It would certainly be suitable for smaller boats.

I later upgraded to a Pentek G3 2x10 housing ($9) and a Floplus 10 cartridge ($16), with about 4 times the flow; all I can use without splashing. I did not filter water for showers; pre-filtered and chlorinated US tap water is more than adequate. Do place any filter on the pressure side of the pump; the pump will cavitate trying to draw through a carbon block or any other fine filter media. I've had the same cartridge for 2 years, allowing it to dry out each winter in the off season and then re-installing. I'm very pleased with it.

The Result. When finished we did a blind taste test with 5 sailors along the dock; not one could distinguish the tap water from Deer Park bottled water (based upon mineral content analysis, the two waters are very similar). For the coastal US sailor, we have improved the taste as far as possible, and reduced the biological risk by at least 3 orders of magnitude. I feel I've reached beyond the point of diminishing returns clear to the point of no return.

I'm sure I've save the price of bottled water, and the reduction in hauling and trash has been wonderful.

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The full version can be found in "Keeping a Cruising Boat for Pennies."

RO Water--What Are We Missing

 (This is a work in progress. I'll be back)

There's been a lot of talk on the web about distilled water and RO water being bad for you, leaching minerals from the body, cause heart disease and all that. Although we filter out most of what we read in the tabloid press and web, perhaps there is a kernel of truth, hear and there, accidentally, it seems. As I begin researching drinking water filtration for a serice of up-coming articles, I find there is substance to to concern over the lack of substance in pure water. While I'm not a health researcher, there is enough scholarly work out there by respected organizations to take seriously. I like reading things from the World Health Organization (WHO).

WHO Symposium on Low-mineral water.
WHO paper.

Please read these at length. Google strings with "drinking water," magnesium," and "calcium." Try to read between the fluff and ignore all sites that are selling something.

There are many concerns; the three that seem best supported by science are:

• Heart Disease. A shortage of magnesium is well correlated with certain forms. Also stroke.
• Kidney Stones. It seems that dietary supplements increase risk, while calcium in the water decreases the risk. Different absorption mechanism.
• Heavy Metal Absorption. If there is enough calcium in the system it out-competes many toxic materials. In fact, precipitation with lime is the basic industrial treatment for most heavy metals.

It seems all of that traditional stuff about healthful mineral waters had substance. Funny how that happens. Funny how your parents get smarter over the years.

What does this mean to the sailor?
 

Even though single-stage RO water (typical sailboat water maker) is not ultra low in Ca or Mg, it is considerably lower than most surface waters and lower than the general guidance available to us. I'm not sure what this means at a practical level. If you swim enough swallow a few mouthfuls of seawater, that's actually a good thing (a few percent seawater will solve the problem). Bottled water helps. Supplements may, but a dash of seawater in the cooking is simpler!

For coastal sailors I think the message is clear; using dock water with some on-board treatment (I'm researching that) is a better bet than running a water maker.