Monday, September 29, 2014

Bleach and Aluminum Corrosion

Rev. 10-14-2014

I've got a series of 4 articles on water treatment coming out in the next few months, describing a simple approach, soup to nuts. One of the more interesting thing to com of it is a treatment that seems safer for aluminum tanks. Both of these images show the worse pit after 14 days, at about 200 magnifications.

Puriclean Aqua Mega Tabs, 1 ppm free chlorine. Later I determined that I could lower the dose 4x below this and still maintain the same free chlorine due to the cyanurate buffering. Overall, the surface has been smoothed rather than pitted, with ~ 50% reduction in weight loss.

Bleach 1ppm, free chlorine.

Safer for aluminum tanks? That is my impression, particularly if the dose is lowered below manufacture recommendations to the lowest effective dose, but more confirmation work is needed.

What about hydrogen peroxide? During the writing of my water treatment articles, numerous sailors asked me to consider H2O2 as an alternative to bleach for aluminum tanks. One problem, of course, the lack of established standards for sanitizing with hydrogen peroxide. The Water Quality Association (certifying organization, similar to NSF) recommends 30,000 ppm hydrogen peroxide (3%), which is full-strength drug store peroxide, and 3 hours contact is required. Compare this to 30 ppm for bleach with a required contact time of 1 minute. There is no recommendation for routine use, but health approvals place and absolute limit of 1000 ppm peroxide, which is most likely below the effective dose. Not at all practical, and any stories of effectiveness at lower levels from cruisers are anecdotal and probably not based upon any science.

But just for laughs I did some corrosion test, using 3000 ppm peroxide for 4 days (ASTM D1384 test coupons at 65F).

No pitting... but remember this would have taken 40 pint bottles to sanitize a 25 gallon tank, even then using only 10% of the WCA recommended dose. Not practical.

  • Aluminum. Minor discoloration, no pitting.
  • Brass. Minor discoloration
  • Copper. Minor discoloration
  • Solder. significant corrosion, about like bleach on aluminum. Expect premature failure.

Friday, September 26, 2014

Fresh Water Flush--a Miniature Water Closet?

Seawater contains bacteria and sulfate. Flush with seawater, deprive the bacteria of oxygen for long, and facilitative (those that can go aerobic or anaerobic) start using sulfate (SO4-) as an electron source. The result is H2S (rotten eggs) and the head stinks. The cure? Either use the head every 8 hours (thus, smell is not a problem when living aboard or actively cruising) or flush with fresh water.

But you can just plug the freshwater pipe into a manual head; water will blow through, flooding the compartment, and bugs can swim up-stream. The water closet, introduced a century ago, prevents both by employing a float valve and creating an air gap (bacteria can't fly, as a rule).

What about a miniature water closet? $38 from McMaster Carr

Made for commercial ice machines, this unit holds enough to flush 3' of 1.5 inch line--not enough for most manual heads--and refills at 0.33 gpm, or about 1:20 seconds per full flush (12 strokes or so). Clearly, a larger size, holding about 60 cubic inches, is what is needed. It could also be expanded by mounting a 1-3' length of 3" pipe under it to serve as a reservoir (4' of hose can be flushed for every 1' of 3" pipe). Mount it to a bulkhead somewhere handy and you should be good to go. A pair of valves would allow switching from seawater and isolation.

But I haven't tried it. I'm happy enough with sea flush and a rinse with potable using the shower head before going home.

Friday, September 12, 2014

Knees, Close-up and Dirty

 The protruding wire does make for some odd bumps and can be sore against pants, and kneeling on the cap is out of the question.
31 years ago during an informal club bicycle race I dodged a pedestrian, got into the gravel, and shattered my right knee cap into 16 pieces. It healed up well, all things considered, though it is lumpy and 20% larger than its mate. I still have some wire, the back side was rough enough that sustained cycling was out for almost 25 years, and I had some permanent weakness in my right quad; I tended to favor it.

A little rough on the backside, but the Doc says it will go the distance. Not bad for that long after that much repair.

The wire broke during the healing process, but its purpose was served. No need to remove it. Notice the spacing is less on the right side, though I may not have been standing straight.

And as a result of favoring it, I tend to come down more straight-legged on occasion, which ironically, is the opposite of a favor. Additionally, having very flat feet (feet pronate inwards), a disproportionate amount of weight is carried on the medial side, in spite of wearing orthodics for the past 30 years. A year ago I felt and heard a pop in my knee when stepping high on a boulder, heel to butt with all of my weight on that leg; I started a tear. It bothered me some, never felt right, but never caught. Then a few weeks ago, while helping my daughter move back into college, the tear spread. I felt like I was taking light loads, not moving too fast, and I never felt anything... until it tightened up an hour later. ~ 8 trips up 6 flights was too much.

A nice little tear. Though it would bear weight, bending the knee more that 10 degrees cause locking and lots of pain.

 Cleaning Up...

And a few signs of wear, but not too bad for an old guy. Should go the distance, with some increasing pain.

While it is too soon to say much, just one day after surgery it hurts less than it did. They say I can go back to skiing and all that, but I think I'm done with that; I know I can't back down from the double blacks, so I'm better off going sailing and wearing a brace, just to be sure.

But for the next few weeks... time to write, I guess.

Update, 9-13-2014. As surgery meds wore off, the pain showed up. I strong recommend getting a Breg Polar Care 500 ($168), whether insurance will cover it or not. My wife had one left over from knee replacement surgery, and this is the only way to keep ice on the knee at night. This really helps with both swelling and pain. The temperature is adjustable, but if you wear an Ace bandage on the knee, the amount of insulation is perfect for comfort. Lasts about 10-12 hours on a fill of ice. The knee version (not pictured but very similar) comes with Velcro.

During the day, packs of frozen veggies (one over, one under) are best, conforming nicely. We get ones we don't like (lima beans) so that we don't accidentally try to eat something that has been refrozen 20 times.

Update, 9-18-2014. I'm mostly off the cane, but I walk slowly and stairs are still far out of the question.Still icing (Breg) at night.

Update, 10-5-2014.  Started on exercise bike. Mowed part of the grass yesterday, but did no try to finish. A little muscle soreness today, but the joint seems fine.

Wednesday, September 10, 2014


After about 5 years of faithful service, my collection of saltwater plugs was looking sad. One fish lost to a hook that snapped off, a little too much metal gone. Time for new teeth.

Is it worth the trouble for a few lures? These are good sized lures, $10-$15 each for 8 of them, so yeah, time well spent. About $2 for the hooks and 15 minutes work, they should serve another 5 years. It's also good to inspect the rig, trim the end off, and tie new knots.

Other lures are generally just replaced. Jigs are cast in one piece, and generally the skirt goes first. Blue fish hose eels are generally too chewed up to worry over, and the stainless hooks last forever.

Boot Drier

A few days ago I was following a thread on a sailing forum regarding how to best dry a pair of high-dollar leather and Goretex seaboots. Suggestions from experts ranged all over, but missed that most obvious answer; a boot drier. Perhaps this won't resonate with warm climate folk, but it should; I've seen enough mold and mildew in Florida to make it the state plant... if it were a plant.

I built this one15 years ago in an evening, for the specific purpose of drying wet snow gear, but it has certainly been used far more for rain soaked gear.

Even the most sodden boots, shoes, or gloves are dry, warm, and fresh in a few hours. Odor is eliminated, as there is no chance for anything to grow. Wet gear has a proper place, and space is conserved since less gear is needed. The materials came entirely from the might-need bin, but I suppose it could be built for $30 if everything were purchased. It could be made longer, for a larger family, with very little change in cost.

The fan provides just enough flow. A bit of flashing creates an internal baffle, directing all of the air flow over the bulb before it goes to the pipe outlets. A 60W bulb seems to provide just enough warmth, but a larger bulb or lamp-base heater could adapt the design to larger sizes. Hardware cloth keeps small fingers and trash out. Pipes could be made longer for sea boots. The unused pipes are plugged by dropping a large bolt in the hole, focusing the heat on a reduced number of holes. The weight is sufficient to keep it from tipping over.

  • 110v computer fan
  • ceramic socket with 60W bulb 
  • box and switch
  • a salvaged cord
  • 3/4" lumber and some screws
  • 3/4" PVC pipe stubs
  • a bit of flashing and some hardware cloth
  • paint
What would I change? I should have built it for 8 pipes (4 boots + 4 gloves) to better serve 2 people. I should have made the pipes just a little longer (no so much that it could tip over) and drilled a cross-wise hole near the end (so that they cannot be blocked if the boot is sitting on the end). But Jessica is off to college, so it's really just me playing outside, and it works quite well as it is.

I've been tempted to build something similar into the boat--it's really sweet to have warm, dry shoes in the winter--and perhaps I will if I start cruising more in the off season, now that school schedules don't matter.  Perhaps something that diverts warm, dry air from the mini-dehumidifier.

Tuesday, September 2, 2014

Idea Drive

I get hooked on testing boating related stuff, On one hand, the projects sometimes become rather time consuming, but on the other hand, when I run out of projects I get bored, and my wife tells me that is bad.

A few of the things I have written about for Practical Sailor, not including follow-ups:
  • Gasoline additives--phase separation (none work)
  • Gasoline additives--corrosion (yup, some really work)
  • Gasoline vent filters--best adsorbants (silica gel lasts for years)
  • Gasoline vent filters--effect on corrosion (yup, helps, may be main factor)
  • Diesel vent filters--effect on corrosion (yup, helps)
  • Diesel additives--biocides
  • Diesel additives--corrosion
  • Wire Corrosion--1-year saltwater environment chamber test of spray and grease inhibitors
  • Sanitation hoses
  • Holding tank chemicals
  • Holding tank vent filters
  • Dehumidifiers and desiccants
  • Joker valves and chemicals (PG antifreeze lost)
  • Joker valves--field trials (Raritan won)
  • Glycols--winterizing, burst point, and corrosion
  • Glycols--biological fouling resistance
  • Glycols--engine coolants
  • Whipping twine
  • Sewn splices--strength testing
  • Abrasion resistant line coatings and chafe guards
  • Mildew preventatives, both coatings and vapor-type.
  • Water repellant treatments for canvas. Long-term.
  • Flexible window materials (Strata Glas etc.) and waxes. Long term.
  • Water filtration--filling the tank
  • Water treatment in the tank
  • Water filtration--final polish at the tap
  • Mantus chain hook and bridle
  • Anti-mildew chemicals
A few things that are in process:
  • Gaffers tape
  • Soft shackles
  • Battery and coolant top-off water
  • One-drop oil tests
  • Gasoline additives--anti-oxidation and gum
  • Diesel additives--anti-oxidation and gum
  • Dyneema lifelines and chafe
What topics are of interest? Test ideas? I do best when there is a chemistry angle, but I'm open to anything; if it doesn't interest me I will pass it along.

Carbon Holding Tank Vent Filter Lasts Over 3 Years

I was told by more than a few that vent filters were too expensive, since the replacement cost was over $100 and they only lasted a year. But my math and chemistry suggested a different story, and in fact, my $15 filter lasted more than 3 years, and the refill was ~ $5 and less than 5 minutes ( I designed for easy changes). A good deal, I think. I sail most weekends and cruise about 1 month each year, in 1-2 week increments.

3 years ago in Practical Sailor I published this...

Why Carbon Can Last Much Longer Than Laboratory Testing Suggests
The primary interaction of carbon with organic vapors is surface absorption, as the Dometic tests explored. However, carbon is a very complex surface and presents very complex behaviors. In the presence of fresh air we have catalytic removal of sulfur by this simplified mechanism:

3O2 + 2H2S --(activated carbon as catalyst)--> (SO4)-2 + S + 2H2O

While this reaction eventually fouls the carbon, it does extend its life by many times. The carbon bed must be sufficient in size, as this is a slow reaction in most carbons, and oxygen is only available in small amounts, provided by thermal breathing of the tank, inflow during pump outs, and slow bidirectional flow in the vent hose. The oxygen requirement is easily met, however, as it is many times less than that required to support aerobic tank conditions. Standard ASTM methods (used by Dometic) are not appropriate for estimating carbon life when catalytic reactions are present, because the method substitutes nitrogen for air, eliminating oxygen from the process.

Among other things, the proposed reaction mechanism predicts that the fouled carbon, when spent, will have sulfur and sulfate on the surface. And that is exactly what I saw; black carbon though 80% of the bed depth, and then whitened carbon  at the tank inlet. I love chemistry.

So, 3 years from now I will need to block out 5 minutes for a change-out.

There a 2 wooden clamps (one at each end) that hold the tube. Loosen 4 screws and the tube is loose. Loosen the right hand hose clamp and the end slides off. Dump and refill. Easy. 

The black rubber boot is a common PVC 2" no-hub connector, stretched to fit over a 2" SCH40 cap. The stretched end is not removed during service. And inexpensive yet removable cap that allows for good compression on the carbon. The 3/4" end fittings are tapped in. Always use fitting when a sharp bend is required; eventually, hose will kink.

Very similar, below is a non-refillable version I built for the Practical Sailor lab tests. Dimensionally identical to my unit and most commercial units. Do remember to settle the carbon into place by tapping the side of the tube with a screwdriver for 30 seconds; if not well settled, vibration in-use and will create a by-pass channel on the side in horizontal installations. A vertical installation avoids this problem (the Big Blue Filter), but a horizontal installation saves some vertical distance and makes it easier to avoid liquid contamination.  So remember the foam pads and tamp the carbon into place.

Monday, September 1, 2014

Sifting Through Old Pictures

Sometimes the basement needs a little cleanup, and since a knee injury has me sidelined from sailing and heavy work, sifting through a box of old pictures was worthwhile enough.

My first boat, Prindle 16, about 1984. Photographed with my mother and grandfather. This was the first day sailing with my new asymmetrical chute. Because the they were nearly unheard of on beach cats, kits weren't available, and I had no money, we sewed this one from a pattern of my own design. Very fast. Later I added aluminum hiking racks, a bow sprit, and some additional roach, which really made her into a speedster that tacked downwind.

Taught me to sailing tender boats fast.

Our first week with our Stiletto 27, Cherokee Sun, 1992.  Later she got repainted, added a chute, bigger motor, and limited cruising amenities.

Taught me to sail tender boats even faster (this one tacked downwind too, with the chute), without capsize, and whetted my taste for cruising.

Jessica's First bluefish. Fun stuff. 

Taught me how to stay a kid. She's in college now.

Saturday, August 30, 2014


Tying up a halyard so it doesn't slap.

Tuesday, August 26, 2014

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.

  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.


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