Wednesday, April 26, 2017

Why is Russia Bombing Blogger Sites?

Historically, Russia represented about 0.2% of my page views. Reasonable enough. More that 95% of the trafic came from the US and UK (England, New Zealand, Australia, and Canada), with a smattering from Europe. Makes sense. These are the people that sail and who speak English.

Starting during the last election, and continuing today, though slightly less dramatic, 10-60% of the traffic comes from Russia. None of this represents sailors or actual viewers. Probing eyes? I can't imagine why. Intentional swamping of data lines? Probably. Sponsored by the Russian government? That seems certain, give the scope and level of control. I must assume this ratio of junk traffic is uniform across the net.

And Putin wonders why relations remain frosty? Does Trump yet fully accept, in his heart, that these people don't use the same rule book we do? Perhaps he is coming to that conclusion, though why it was not school-boy obvious last year I can't guess.


Monday, April 24, 2017

Attainable Adventure Cruising

It's not smart to advertise links to sites that could siphon readers and dollars away, but sometimes you run across a page that simply must be shared. Though I have never met John, I have exchange considerable correspondence and consider him a friend, for the good character and free exchange of ideas he has shared. His site (https://www.morganscloud.com), complete with on-line e-books, is a treasure.

jhhomd1-8300796

Do I agree with him on everything. Heck no. I don't agree with myself all of the time. I have more of a coastal and multihull perspective, and he has an off-shore perspective. But John displays rare combination of open mindedness and traditional, conservative seamanship that is extremely refreshing. I respect his opinions, always.

Saturday, April 22, 2017

Coal is Not Coming Back

This is NOT me getting political. This is simply a list of observations on how Appalachia has been bamboozled.

  1. Pipelines = Cheaper Gas. More pipelines mean reduced oil and gas prices, meaning less reason to burn coal. Although coal remains cheaper than gas, there are more costs associated with burning coal (unloading, stockpiling, grinding to dust, emissions controls, boiler fouling, increased wear, coal ash disposal). And since most people like cheaper fuel and gasoline, most people at least tacitly like things that make gas cheaper. This will lead to continued at least quiet bipartisan support of fracing.
  2. Time Line--Utility Plant Move Slowly. Even if coal were significantly cheaper than gas--which more pipelines and drilling prevent--power plants are decades in the planning and construction. If you were budgeting for a power plant, would you propose coal, knowing that the neighbors will oppose permitting and that the regulatory pendulum will swing back in 4 years, but no more than 8? No matter my political temperament, I would not see this as a long term strategy. I would not stake my job on a coal-burning plant that would be shut down a few years after it opened. Therefore, planning of new coal plants is very unlikely. At most a few might go through a few motions, but they won't commit the money.
  3. Clean Coal. I'm an engineer and like the science. But I wouldn't invest in something that is economically marginal and still politically vulnerable.
  4. Most States Determine Their Own Rules.  I know several coal plants that were closed, all the result of local pressure. States can set their own rules. A change at the federal level will have no influence on most closures. Finally, no matter how conservative the voter, no coal plant will receive support at the local level (NIMBY).
  5. Health Care. Unemployed miners should be able to figure out where that is headed.
They allowed themselves to be distracted by glitter and words they wanted to hear, but that just couldn't be true.Times change, they always have, and it's a little cruel.

I'm not even sayin' whether this is good or bad, it's just what the facts reflect. You don't put the genie back in the bottle. Historically, can't ignore the bloody shirt, and there is a case against coal that goes far beyond global warming.

Wednesday, April 12, 2017

Happiness

Life consists of many part and moods; when my thoughts drift to what is important, I think of Lin Yutang and The Importance of Living. It belongs in the library of any philosopher, and no sailor, climber, or person wanting to milk the full value from life can not be a philosopher. From a chapter on happiness, adapted to my experience (inspiration from Chin Shengt'an):

_______________

My Seven Happy Moments. There have been more, and will be to come, but these few thoughts step forward today:


  1. A Cigarette boat comes joins the 6-knot parade out of the the harbor through a narrow channel. But he can't wait in line, guns the throttle, passes to starboard, and runs definitively aground in 12 inches of water. When you return to the harbor after a brief sail, the young men are still aboard, arms akimbo, visually proclaiming "we're cool." Is this not happiness?
  2. You are anchored in a pastoral cove, alone with your thoughts. There is only the faintest breath of air from the east, just enough to swing the boat, but not enough to ripple the water. It is not hot, just warm. Without a cloud in the sky, the sun is a low, an impossibly large red orb that cannot last. Is this not happiness?
  3. In preparation for a climbing trip to the Wind Rivers and Tetons that will involve long pitches on snow and ice, you climb pitch after pitch of easy rock rock at a convenient crag near home, unroped, to build speed and confidence. Nearing the top of a straightforward 5.5 crack, you overhear several 20-somethings chat about how difficult the climb was (with a rope), lament that there fathers could not join them, but allow with great understanding that "Dad is in his 40s" and it's unrealistic to expect so much. I easily top-out sans rope, and while walking past them mumble that I'm 48 (some years ago) and that my 12-year old daughter also enjoyed the route. Is this not happiness?
  4. I sit in the backyard with a good book (Lin Yutang), with DEET-based bug repellent on one leg and catnip-based repellent on the other, the stuff of another article research project. The DEET leg is all alone, and the mosquitoes only circle the other, confused and unable to process critical landing information regarding the tasty mammalian flesh below. Is this not happiness?
  5. Since my daughter was old enough to baby sit, she would fill bags with teacher-like stuff and spend hours developing an activity plan and preparing for her "job." During her senior year of high school, after several false starts, she announced that she knew what she would do in college. She is going to be a teacher (this was some years ago--she is student teaching now). Is this not happiness?
  6. Your career of 32 years comes is victim to massive consolidation following a merger with a company that does not understand what you do. At the same moment, you realize that for the first time in your life you have a chance to chose your path. A cross roads to be faced as an adult, with all of life's experience to draw upon. Is this not happiness.
  7. My daughter is home on break from college. We are sailing in light winds and she is collapsed, semi conscious on the bow. Is this not happiness?
 The kids, armored against jelly fish.
_______________

 Sometimes I write solely to practice putting words on paper in a thoughtful way. Unfortunately, I don't have a philosophy sufficiently considered to express at length. Whenever I examine it closely, it flits away, unwilling to pinned down or well understood. Faulkner said that "free time only exists when not measured" (The Sound and the Fury), and so perhaps philosophy can only be fresh and thus worthwhile so long as it is unexamined, not ruined by anything more than a furtive glance in its general direction. Maybe it's simpler than all that. We should just be happy.

Friday, April 7, 2017

European Paddle vs. Greenland Paddle

For an old guy, Greenland paddles win.

A Euro paddle blade is leaf-shaped, nearly half as long is it is long. Or rather that is what we have come to accept as normal and 21st century. It is superior for whitewater kayaking and racing, where it provides a positive, even harsh grab on the water.

But over the years I've run into folks using Greenland paddles with their sea kayaks.  Though the urban legend is that they were long and slim because that is the only thing they could make from drift wood, when you consider the craftsmanship that goes into a skin-over-frame kayak, that sounds like lame reasoning; these people could craft anything from a few bits of wood and sinew, and in fact, they used broad paddles in other craft. They developed what we now call the Greenland paddle because it has some unique advantages.

These are works of art. Mine was fashioned from a 6' x 3/4" x 3 1/2" (a common 1 x 4) board and a center of aluminum tube in a few hours, and probably performs better.

The length is about the same--a little less than 8 feet. The blade in only 1/2 the width of a Euro paddle, but the length of the blade is over double, resulting in greater projected area. Because it is not scooped like the Euro paddle, the catch is much softer, and it does not generate as much instantaneous power. However, because it has a higher aspect ratio, it actually creates greater lift once the stroke is underway.
  1. Lighter. My Greenland paddle is 25% lighter than my fiberglass Euro paddle.
  2. More buoyant for rolling. 
  3. More lift when used in a sweep stroke for rolling or bracing, because of the higher aspect ratio.
  4. More resistance and better grip on the water at mid-stroke.
  5. Smoother catch and release.
  6. Easier on the wrists, shoulders, and elbows.
  7. Quieter.
It was "1" and "6" that caught me attention. Although it does not provide the same acceleration, it is faster through the water over the long haul, easier on the body, and significantly lighter. I'm still not used to the look, but it is more efficient over a long day.

Downsides? A few, but they are minor.
  1. Harder to buy. But you can make them rather easily. They don't need to be laminated and beautiful.
  2. Not as much blade in the water in shallows. But you can use a shallow, more horizontal stoke.
  3. Most designs do not feather, but that can be fixed by incorporating an adjustable ferrule. 
  4. Typically the shaft is fatter (1 1/2-inch vs. 1 1/4-inch standard or 1 1/8-inch small). Hand size and whether you wear thick gloves (a smaller paddle works better with thick gloves) may dictate which is better, but I find the fatter shaft is harder on my wrist and hands. Personal preference enters in. 
  5. Learning a new stroke. Where a Euro paddle is simply pulled, the smoothest and most powerful stoke on a Greenland  paddle is delivered by a gliding pull with the blade moving at an angle, as when swimming the crawl efficiently. The blade is high aspect and generates a lot of lift when moving sideways. the stoke is also lower angle.

Feather. Most sea kayakers adopt a feathered paddle after some experience. By angling the blades about 60 degrees relative to each other, even when the arms cross between stokes, the wrists remain in a neutral plain, never flexing. The key is to pick a control hand that grips the paddle, and to let the shaft rotate in the other hand during the cross over. The non-control hand need never grip the shaft tightly. Gloves help.

Whitewater paddlers often use an non-feathered paddle--it can be problematic to keep track of the twist angle when paddling rapidly or throwing out a quick brace stroke. I use zero feather in technical whitewater.

Greenland paddles are typically not feathered, because a more shallow stroke is used, minimizing wrist flex, and by tradition. Many paddlers find an non-feathered paddle easier to roll, because similar to the whitewater case, they don't have to remember the feather angle. However, I have wrist problems and really like feather, although less than the traditional 60 degrees used with Euro paddles. My Greenland paddle is feathered only 30 degrees.

It's  little ugly, but by using aluminum tubing in the center I dropped the weight to about 65% of a common paddle and gave it 30 degree feather.  I am wondering if less or even no feather might be best for Greenland paddles. It may be a matter of learning a new stroke.


Where can you get a Greenland paddle? First, make you own. There are many on-line sites with instructions, and if you are handy in the wood shop, a basic paddle won't take much over an hour or cost more than $5 to make. You can buy them, of course, but artwork and craftsmanship cost money.

If you want adjustable feather or a Greenland paddle that can be broken down for storage, Duckworks sells carbon fiber ferrules for ~ $25. This also makes it possible to create feather. Duckworks offers two ferrule options:
  • Standard. Allows for O degree, 60 degree right, and 60 degree left feather. The shaft is 30.6mm (1 1/4-inch), which is generally considered standard for kayak paddles.
  • Greenland. There is no allowance for feather, although you can obviously mount the ferrule with some rotation to create a fixed feather angle. The shaft is 38.6mm (1 1/2-inch), the traditional fatter Greenland paddle diameter. 
Additional holes (you drill em') can create custom feather angles.


This is the elegant way to do it [details on Duckworks]. Add a slightly longer center section and 30 degrees of feather, and this is my dream paddle!





Saturday, March 18, 2017

Internal Reefing and Friction

Single line reefing can be a delight, until the friction become so great nothing will move. I was pretty fed up with mine, when I first go the the boat, until I realized the PO had left me a tangle. A simple problem, and easy to fix, but often overlooked because it is out of sight.

The problems is that there are blocks inside, and when these get twisted, they lock up. The twist is introduced by a group of turning blocks near the mast (different from this illustration), that guide the line back to the cockpit or to a winch. Every time the reef is used, their corkscrew arrangement walks a small amount of twist into the boom.


The cure? Look in the boom-end to confirm that this is the problem. If yes, go the mast-end and untwist the line by hand in the required direction, until the lines are straight and the blocks are vertical. This may take 5 or 6 turns. Chase these twists through all the way back to the cockpit, so that they are not simply stuck between blocks near the boom. Do NOT release the line from the end of the boom and try to fix the twist from there. Although that end is also twisted, that is only a symptom of the twist at the other end. There is no way for twist to sneak in from the boom end, and if you try to fix it from there, you will simply create opposing twists. The problem originates at the boom end and must be fixed there.

On my boat this must be done about every 50 times I reef. Not very often at all. But if you've waited years, or if the boat is new to you, look inside the boom.

[This image is from the PDQ 32 Owner's Manual, free in MS word if you request it via the contact form near the bottom of the right column.]

Wednesday, March 15, 2017

Cleat Strength


 Boat US did a study, bolting cleats to steel plate and breaking them. Obviously, on a boat, this depends on a strong backing plate.

Different size cleats? In the case of fastener failures, simply adjust in proportion to the fasteners you have (data found here). In the case of feet failures, expect the strength to go up size^2. The strength of the foot, for example, probably goes up with size^3, but leverage goes up with size^1.




Tuesday, March 14, 2017

Marking Anchor Chain

Someone once told me that marking anchor chain with paint was amateurish.

Sailors on the US Blue Rige (LCC19) touch up the chain markings.

Okay, sure. 
  • They suggest that you can feel bits of cloth and such in the dark. Assuming the gypsy don't sheer them off or jam, please don't tell me you would run your hand along a running chain in the dark. That is a good way to lose fingers.
  • Plastic ties. My windlass sheers them off no matter how they are attached. Some manual say there is a right way, but not with a Lewmar vertical.
  • Inserts. If I can't see the paint, I'm going to be able to make out a few mud-coated lumps in the dark? Silly on the face of it. 
The first article in Good Old Boat Magazine described a better way to paint the chain. Also in "Keeping a Cruising Boat for Peanuts" and "Rigging Modern Anchors."

 They even have a standard color code. Not sayin' you need to use it, although I do use a long red band to warn me of the rope-to-chain splice at 100 feet (98% of the time I stop short of the splice so that I can anchor on all-chain.

After all, you always need to know how much rode you have out.  It's all part of good anchor craft, along with proper snubber sizing (Practical Sailor) and one hundred other factors.

Saturday, March 4, 2017

PDQ 32 Owner's Manual

I've scanned the manual that came with my boat, converted into MS Word, and adapted it a little my specific boat, modifications and all. I figure it's a nice courtesy to the next owner, and something that will help maintain PDQ value for all of us.






PDQ Yachts Inc
Whitby, Ontario
Canada


Revised for Shoal Survivor, HIN XXXXXXX
1997
Rev. August 20, 2015
February 2017


If you would like a copy, just send me an e-mail via the contact form at the bottom of the right column. No sweat.


I recommend converting it to PDF (MS Word will do this) once you have customized it. It will scroll MUCH faster.




Thursday, March 2, 2017

Mexican Navy Tows Disabled Sailboat for 1 1/2 Days.

Described in the link below, a sail boat became disabled when their rudder sheared off, 3/4 of the way from Texas to Mexico. The US Coast Guard contacted the Mexican Navy, and the Mexican Navy sent a 180-foot cutter to provide a tow.

http://www.click2houston.com/news/mexican-navy-comes-to-rescue-of-stranded-american-sailors

Without getting political, it's something to think about. Things do go both ways. I like to get along with my neighbors. It seems to work out better.

Of course, a proper steering drogue would also have solved the problem, just as quickly and with less drama. After my own experience with bending a rudder on a submerged log (repair described in "Keeping a Cruising Boat for Peanuts"), I did considerable research on drogues for emergency steering and storm management, learning that a good drogue is a solution even a singlehanded sailor can make work in minutes, with just a little preparation and practice. In the above situation, I would have had a steering drogue in the water within 5 minutes, and we would have been on our way, a knot or two slower, but with certainty.

A failed rudder is simply not a valid cause for rescue or loss of your boat; I've sailed hundreds of miles with no rudder or worse, a rudder jammed to the side. It's quite manageable.

See "Faster Cruising for the Coastal Sailor" for the details. Also, and up-coming article in Practical Sailor will describe the details of rigging and using a drogue. In "How Much Drag is a Drogue" (Practical Sailor, September 2016) I tested, reviewed, and list the relative drag and performance characteristics of most popular drogues.

(Up-coming article in Practical Sailor on Emergency Steering with Drogues)




Monday, February 27, 2017

Boat Writer's International -- 2016 Marine Writing Contest



 In its 24th year, the BWI contest attracted 151 participants submitting 378 entries. In addition to cash awards, Certificates of Merit were presented to writers of another 43 articles which scored within 95 percent of third-place tallies in each category. All submissions to the contest were published in 2016. Each of the categories (noted below along with sponsors) was judged by four active journalists in the first few weeks of the New Year. Links are provided to the top three scorers. Results (there are 17 categories):

Gear, Electronics & Product Tests – sponsored by Xantrex/Schneider Electric
1st, “Splash Test Dummy” by Drew Frye (Good Old Boat, Sept.); 2nd, “New Options in Small Outboards” by Darrell Nicholson (Practical Sailor, Jan.); 3rd, “Hitting the Bricks” by Nigel Calder (PassageMaker, Sept.). “Despite it being a controlled product test of a cold water immersion suit, the author packs the article with a satisfying mix of information and hard data, accented with a good dose of humor throughout – An excellent piece of professional journalism,” noted judge Rich Armstrong. Merit Awards: “Trial By Fire and Water” by Lenny Rudow (Texas Fish & Game, Sept.); “Fish Whisperers” by Ron Ballanti (Anglers Journal, Fall).


Seamanship, Rescue & Safety – sponsored by Sea Tow Services International
1st, “The Storm Trysail” by Edward Zacko (Good Old Boat, Jan.); 2nd, “In the Perfect Position to Fail” by Ralph Naranjo (Practical Sailor, April); 3rd, “Naked and Afraid” by Pete McDonald (Boating, Jan.). Of the first place selection, judge Jim Rhodes said, “A thoroughly researched and well-presented article. Punctuated by vivid personal anecdotes, it was written with the authority of someone who knows the subject matter.” Merit selections: “Hitches to Grip Anchor Chain” by Drew Frye (Practical Sailor, May); “Go Forth and Cruise” by Tom Cunliffe (Sail, June).

Friday, February 24, 2017

Chafe-Be-Gone


Yale Maxijacket 


I investigated this product primarily on a whim. I was working on an article on chafe protection, and Practical Sailor asked about trying coatings, just in passing. After all, what can you expect from a product that looks like nothing more that water-based varnish? Obviously boat show advertising hype. Someone had also  given me a sample of a related product, Spinlock RP25.


 Both sides were cycled across a grindstone for 2000 cycles: Spinlock RP25 on the top and Maxijacket on the bottom. A baseline test (no coating) reached the RP 25 wear level in 1000 cycles.

I was dead wrong.

Maxijacket. The only things that lasted longer were tubular nylon webbing (5x) and Dyneema chafe sleeve (20).
  •  6-15 times longer than uncoated rope
  • 10 times longer than clear vinyl tubing
  • 2 times longer than APX aramid chafe sleeve
  • 3 times longer than 1/8-inch leather
RP 25. Good for stopping core slippage, but less so on chafe.
  • 2-3 times uncoated rope (greatest improvement when wet)

Applications? I've been using the stuff for 4 years and remain very impressed.
  • Docklines. Anywhere chafe gear won't fit.
  • Furler lines. Best for roller reefing, where the line is highly loaded.
  • Any splice subject to wear.
  • Fabric prone to abrasion.
Mooring lines, with and without coating. I tried chafe gear, but it kept creeping off. This is easier to clip and extends the life of the wear section to match the rest of the line.

Topping lift. Abrasion was the problem, so I used some webbing as a thimble and dipped the whole knot. This allows me to down-size from 3/8" to 5/16", saving some windage.

It seems impossible that a product resembling thick latex varnish (stick with clear--other colors can transfer) can make such a a difference. While West Marine charges more than you want for more than you need, Knot & Rope Supply sells a small jar--probably all a sailor needs for a few years-- for $7.10. A bargain.

The Spinlock RP25 does have its applications too. It performs better on HMPE ropes (Amsteel et. al.), reducing both wear and cover/core slippage, and has the flexibility to use on running sections of rope. I'll use RP25 on sections of my Amsteel lifelines.



A penny-pinching tip.

A good-seamanship tip.

-------

Instructions. Whatever they say on the can. These are just my observations. When in doubt, let it dry longer before exposing to heavy load--it will wear longer.


To coat a long line, such as a furler control line, stretch tightly between 2 points.

Maxijacket. By all appearances, it is a thick latex varnish. Any brush suitable for water-based paints will work fine, and clean-up is easy. Apply in one heavy coat, soaking in as deeply as possible. Some riggers favor dipping splices, but this does not increase chafe resistance, wastes material, slows drying, and makes the splice too stiff--just coat the outside. Don't bother with a second coat--it will just sit on top and do nothing useful. Don't try a light coat--that blocks penetration. Allow to dry to the touch before installing, several days in good drying conditions before using, and a week before or soaking (anchor bridles).

RP-25. Petroleum based, it is relatively tine and soaks in rapidly. One very heavy coat is preferred. It will not stiffen the line as much as Maxijacket, but it will lock the cover to the core (halyards and furler lines that have been stripped) and will give some chafe resistance. Slower drying that Maxijacket; allow to dry to the touch before installing and one week  .

------

Since this study, more players have entered the field, and thus an up-dated review is in progress, including additional products from Flexdal and Marlow. Practical Sailor, of course.

Friday, February 17, 2017

Book Store Up-Date

The Book Store has been updated.
  • Two new titles:
    • Keeping a Cruising Boat on Peanuts
    • Faster Cruising for the Coastal Sailor
  • Four titles are now available as PDF:
    • Keeping a Cruising Boat on Peanuts
    • Faster Cruising for the Coastal Sailor
    • Single Handed Sailing for the Coastal Sailor
    • Circumnavigating the Delmarva--A Guide for the Shoal Draft Sailor
  • Table of contents preview is available. 
The anchoring book ("Rigging Modern Anchors") has been a very serious undertaking and will hopefully be going the conventional paper publication route. It contains a lot of new research and I've had some good reviews from within the industry.

 This is where most of the work gets done. There's a lot more to it than typing.

Thursday, February 16, 2017

MastMate--Climbing the Mast the Easy Way

Rope-based mast climbing systems are all the rage--and they do have the advantage of simplicity--but my good old rope ladder has served me well for 25 years. Heck, the surveyor I used on my current boat used a Mast Mate. But there are a few tricks that help.

The most common criticism leveled against hoisted ladders, like the Mastmate, is that the sail must be lowered and removed from the  track. In actual fact, the sail can remain in place, either stacked on the mast or hoisted.

A climbing harness would be much better.
  • Hoist Outside the Track. The instructions are adamant that it MUST be in the track, and it does climb a little easier that way, but I've been setting it free for 20 years. After hoisting to the top, lower 6 inches, clip the lowest eye to something solid, and tension hard with the halyard winch. To me, it simply isn't worth unloading a part of the sail, opening the mast gate, and fooling with 30 slugs.
  • Wear a Climbing Harness. It should fit tightly enough on the waist that it can NOT be slid off, even if you were to fall upside down. If this is not possible because of physique, you cannot climb.
  • Use a Second Halyard as a Safety Line. I tension the spinnaker halyard and secure it to the mast base. A run an ascender (rope grab) up the line to protect against falls and to allow rest. Alternatively, a crew member could tail it on a winch.
  • Wear slim profile shoes. Easier to get in the steps. I'm happy with deck shoes. Most running shoes stink.
  • When not in use, store the ladder coiled, from top to bottom, with the steps flattened in the correct position. This will insure that they open correctly and will make hoisting easier (won't catch on the spreaders). Secure with twine to make certain it stays that way. when hoisting, open the steps as they go up.
Coil for storage. I'm a "crammer" by nature, and I can tell you from experience, it is a mistake.
  • Carry Several Slings for Securing Yourself at Work Points. 4,500 pounds minimum breaking strength.
  • Do not carry any tools while climbing. Haul these up with a trail line. I like an electricians bag.
  • Haul up a climbing rope. Use this to rappel down, saving time and effort.
  • Wear gloves while climbing. Vinyl coated work gloves like Atlas Fit grip the mast well.
 I dump the tools out and take only what I need.

Saturday, February 11, 2017

Book Questions, Comments and Research Ideas

Something in the text is unclear? A subject you would like to see researched and written up? Please post the question here. I'm always searching for new subject matter.

Stainless Steel Bolt Specifications

Whether bolting on some new project, or trying to understand why something failed, you need to know how much a fastener can hold.


Clamping Force. When torqued to ANSI specifications, this is how much a bolt will hold before it becomes loose due to stretch (bolts stretch under tension--everything does). If the bolt cycles past this load, it will move around, the hole will be damamged, and something will break. Additionally, this is beyond the working Load Limit (WLL), so we wshould never get here.

Sheer Strength vs. Tensile Strength. Only important so that we understand that they are slightly different. Since most loads are a combination, the WLL is conservatively based on sheer strength.

Working Load Limit (WLL). There is no universal standard for determining this figure. In safety critical applications and applications where forces are not well defined the safety factor is greater than low risk applications and those where the forces are static and well known. The total number of cycles and corrosion matter. For the purposes of this table I set it at 4:1 based on sheer strength.

Backing Plates. The need depends entirely on the strength of the base material. Obviously, a 1/4-inch bolt passing through a 1/2-inch steel plate does not need a backing plate. It does need a standard (bolting ) washer to provide a smooth bearing surface while torquing it down. However, when fastening to fiberglass, ANY SIZE steel bolt, even combined with an ANSI bolting washer, can exceed the compression strength of fiberglass, no mater how thick. The fiberglass will crumble and crack. I did a bunch of instrumented testing for articles using both thin cored laminates and solid glass, and several simple rules of thumb emerged:

  • Backing plate size: 5 bolt diameters minimum. 7 bolt diameters for thin skinned cores.
  • Backing plate thickness:
    • Stainless Steel--1/2 bolt diameter
    • Aluminum--1/2 bolt diameter. A bolting washer is also required. Not for damp locations; I've seen plates just crumble away in anchor lockers. Fine in a dry cabin.
    • Solid fiberglass--1 bolt diameter, unless bonded directly to the laminate. Then 1/2 bolt diameter. A bolting washer is also required.
    • Wood. Not recommended due to rot and splitting potential.
      • Plywood--2 bolt diameters. A bolting washer is also required.
      • Hard wood--3 bolt diameters. Not recommended, since all of he test samples failed by sudden splitting. A bolting washer is also required.
    • HDPE (Starboard). Not recommended. All samples gradually bowed and cracked under sustained load. Just don't do it.
  • Bond the bolting plate to the substrate if possible to insure good contact. Vital if the surface is very rough or curved. The bonding can be weak material, such as sealant. 
  • Threads. A single steel bolt will hold full tensile strength, even though it will strip before the bolt breaks when turned. The required thichness for the threads to hold full bolt tension varies with the material and how well the threads are cut, but is aproximatly:
    • Steel. 2/3 bolt diameter.
    • Aluminum. 1 bolt diameter in spar alloys.
    • Fiberglass. 1-2 bolt diameters, depending on the density of the lay-up. 1 bolt diameter in G10 and most pre-cast laminates. No standard value for cored laminates, HDPE  (creeps) or wood.
No guess work, just solid engineering principles, though even engineers go up a size when there is something they can't be sure of.




Tuesday, February 7, 2017

Paint Testing in Estuaries

Practical Sailor does a nice job of testing a huge slate of paints in Florida seawater, and occasionally other locations (New England, Australia). Just this month they have a nice round-up. But in many estuaries paint selection can be very local, the salinity and pollutant load situation specific. So run your own private test. When you consider what bottom paint costs, this is quite practical. Share the work and expense around the marina, and it's chump change. Every full-service marina should do this.

  • Panels: 16" x 48" GRP shower surround material from Home Depot. Since I use this for many other projects around the boat (window covers, wire guards, small fabrications), this is just scrap.
  • Floats: 2" x 60" PVC pipe with the ends capped.
Mask the panel off into rectangles and paint. The number of coats varies, but I would use 2 for 20year paints and 1 for single season paints, since that is how they would be applied. Drill holes every 12 inches and connect the  float tot he panels with 3/16" clothes line or equivalent.  Suspend so that it floats with the tide.








My test panels are actually for an article on cleaning method (one is not cleaned, and others will be cleaned using different sorts of scrubbers), but this is the basic paint testing set-up.

I would not bother in seawater--the Practical Sailor tests should be good--but in the upper Chesapeake Bay, for example, this seems obvious.

If I learn anything cool, it will most likely show up in Practical Sailor.

Monday, February 6, 2017

Why Bow Sprits on Cruising Catamarans?


I thought about adding one to my PDQ. I really did, after seeing all the pretty ones at the boat show. I had the surplus parts all lined up to build a good one for $20. Then I came to my senses, realized they are nothing more than marketing bollox, and perfect my bridle instead.


I do understand why they exist. My first boat, a souped-up beach cat, had one to carry a chute, and the boat was considerably faster than the wind. Even reaching deep downwind, the apparent wind remained forward of the bow. Jibing through 90 degrees I would actually tack, with the eye of the wind coming from in front of the boat, not from behind. Same with my Stiletto. Fast boats.

A bowsprit increases projected area, allows a larger chute, and most importantly, it provides enough separation between the spinnaker tack and forestay for fast inside jibes (remember, these boats actually tack down wind).

But the math on a cruising cat, even a relatively fast one is very different. The fastest course down wind  moves the apparent wind well aft. Jibes are outside because the apparent wind moves astern when jibing. Thus, a bridle provides more projected area and reduces the chance of running your sheets over mid-jibe. It is also lighter, does not contribute to pitching, and does not pound through waves up wind.

(With a bowsprit that long, the sheets are way out there. Just a little slack, the lazy sheet goes in the water, and a second later it is around the keel. Catamarans are less prone to this because the broad bows catch the sheets.)

For any boat that can't sail above wind speed with the wind at 135 true, bow sprits are pure marketing poop. I've had them and I know the math.

 

This is what you actually need. Lighter, faster, stronger, cheaper. All the good words.

(Excerpt from up-coming book on Cruising Faster.)