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Fairlead Friction Uncovered
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Have you ever wondered hom much, if anything, you are giving up by using fairleads instead of blocks? How much friction is there. How does this compare with a block? Does the style of the fairlead matter? This article attempts to answer these questions.
Using a digital scale, I was able to compare the no fairlead force required to just move my weight against the turning block that I had on the test bench to the force required to move the weight when there was a bend through one of two types of fairleads. I took data at many angles with both fairleads. I also took some data with different line types, specifically Samson XLS and Amsteel. |
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Jibsheet Fairleads
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Do you find that you get wraps on your jib winches or just want give a better lead angle to the winch? In the last race we did, a new crew member got a wrap so tight that the only way to release it was to cut the sheet with a knife. We strung the lazy sheet to the secondary winch and took the pressure off but that was not enough to free the wrap, that is when the knife came out. The winch manufacturer recommends between 3 and 8 degrees as the ideal sheeting angle. |
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Unique Mainsheet System Analyzed

It isn't often you see a completely new way to rig a mainsheet. I saw this posting on Sailing Anarchy and though I would share an analysis of what they are doing and why. Here is a picture of the boat
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More on Rings as Twings, Inhaulers, and Fairleads

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Calibrating a Marine Compass

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7-Day Tide and Current Forecast
Improved 2/27/2013 - Graph now goes midnight to midnight. Added title to each section.Tables and graphs for selected tide or current station for the week ahead.
Table shows high and low times for tide, slack and peak for current. Also shows sun and moon events. Graph is as shown below. The final table shows the hourly values.
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Low Friction Rings Mechanical Advantage
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Using Low Friction Rings instead of Blocks I recently saw a picture of a three stage cascaded block system using low friction ring instead of blocks. This article analyzes such a cascade and shows how to calculate its effective mechanical advantage. The techniques shown can easily be extended to other systems. I will discuss one such system that I use on my boat. Mechanical Advantage To analyze a system like this you need to know the efficiency of a single stage, extend that to the the efficiency of the entire system, and translate that to mechanical advantage. For reference lets consider the following sketch. |
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Make Your Own Telltails
By: Ed SinofskyI admit it, this is sailing nerdiness at its extreme. When I was a teenager I was a sailmaker at Spencer sails in Huntington New York. That was almost 40 years ago! I used to make the telltales when I worked there. It was always fun bringing pockets full out to customer's boats and giving them away like bringing cake or wine to a visit.
I'm no longer a sailmaker, but over the years I have fine-tuned the design. As winter sets in, I always like to make a nice big batch just to keep myself occupied. I thought some of you might be interested to see how I do it.
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2013 Racing Rules of Sailing -- When Boats Meet
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With a new year comes new rules. Nothing major changed this year, just clarifications and a few changes to keep people from "working the rules". If you sailed to the intent of the old rules, nothing changes. Here is a link to just the definitions and section 2, When Boats Meet. This is the part every racer needs to know and the source of most discussion of the rules. | ![]() |
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GPX and CSV Waypoint Editor and File Converter
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This tool can be used to convert any Garmin gpx file to a StartLine csv file. In addition, you can use this to read your gpx files into Excel or Word processor for analysis, viewing, or editing. GPX -> EDIT -> CSV GPX -> EDIT -> GPX CSV -> EDIT -> CSV CSV -> EDIT -> GPX |
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Buying New Sails?
by Harry Pattison![]() |
New sails represent one of the biggest investments you make in your boat. So when getting ready to make that purchase what things should you consider to make sure you get the product that best fits your needs and to insure you spend your money wisely?
First make an honest assessment of what kind of sailing you will be doing. Broadly sailing falls into four categories; offshore cruising, local cruising and recreational sailing, cruise/race, and racing. The type of sail material, type of construction, and the price to some extent will be determined by this decision. |
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Stray Current Can Drop your Mast
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You would think that having researched and witting an article on galvanic corsion that I would know better. But when I installed my antenna on the pulpit thus grounding it, I was only thinking about the VSWR and antenna performance. Little did I know I was going to cause a failure that not only could have but probably should have taken my rig down.
The coorsion was caused by a 20mA current that was sourced by the potential difference between my newly cleaned (after inspection) bronze chainplate and the zinc on my prop shaft. The path was the bolts holding in my chainplates to the chainplate to the shroud to the bronze ring around my lifeline to the lifeline to the stern pulpit to the antenna ground to boat ground and finally to the zinc on the prop shaft. The connection between the shround and the lifeline was the same as it had been for 50 years but I guess this time it make electrical connection or perhaps it was the different type of twine I used to lash it. That could have held water where the old twine didn't. In any event, in just a few months (May to September) this damage occurred. It is truly amazing that during the race we did the day before ... |
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Rock Box Blue - First Look
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It will not come as a surprise to readers of L-36.com that I was a little disappointed to see that there was no "time to line" function (yet) in the new Rock Box Blue. But if you watched any of the Olympics or the America's Cup you see that the vast majority of starts today have boats lining up at a distance from the line and starting their accelerated run seconds before the gun. For those kind of starts, the Rock Box is a perfect match. Having a 50+ year old 12,000 pound boat, I want more than that and the developer of the Rock Box points out that there is more to come on this really solid platform. That said, the new Rock Box is an impressive product. The waterproof case, O-ring sealed looks solid and well made. There is more to this product than just the start function as I will explain below. |
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Buying Used Sails
by William Posner![]() |
Given the cost of purchasing new sails for your boat these days, some are turning to the used sail market. Here at Pacific Sail Trader we wish to give you the lowdown on how best to do it.
Purchasing a sail without seeing it in person is the greatest concern of most buyers. Not being able to actually touch it seems to be the missing sense. Will it fit correctly? Of course a seller that will provide not only accurate measurements with the sail pulled taught, but showing photos of the good and the bad can help as well. If there are patches or repairs, are they shown? Seeing the corners is key. Often the original owner, especially if a racer will have written the luff , leech and foot measurements as well as the date those measurement were taken. Getting the build date is a plus! Let's say you see that the corner rings are reinforced with leather.Well that's a clue as to the age as it has been many years since that was a standard feature seen on sails. |
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