Thursday, December13, 2018

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Creating the Easy to Use Waypoint and Route Program

This winter I am racing on a Tartan-10, not my L-36. We are racing the winter series out of South Beach Yacht Club and another one out of the Golden Gate Yacht Club. The skipper doesn't use a GPS and as I find them indispensable in sailing to a mark and in calling the layline, I brought my wrist version along. But first I needed to program in the waypoints and routes. What a pain. I used OpenCPN and plunked a waypoint down over the marks on the map. Entering the routes was the most difficult. That led me to build the waypoint and route editor. Then I thought, wouldn't it be great to just have a list of all the marks in the area and just check them off, rename them to match the names the race committee uses, import them into a program, copy and paste the race committee routes onto a page and press a button (after a little editing perhaps) and have a file you could download into your GPS? So I built just that.
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GPS GPX Batch Waypoint and Route Creator

Entering routes into a GPS when you have a number of them to enter is easy with this bulk route editor. Import waypoints from a gpx file or enter directly into this page, then simply write out the routes all at once and create a custom gpx file with the waypoints and routes ready for export to your gps device or chart program.

As an added bonus, Latitude and Longitude can be entered in almost any format, even both in one input box, for ease of copy and paste entry.

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Latitude Longitude Converter

Convert between different latitude and longitude formats. Then copy and past the converted format into other programs. This program will take most any format as input and outputs the result in five different popular formats.
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Gross Fine Mainblock Reeving

mainsheet_lazy_lightning Two ways of reeving the mainsheet in this gross fine mainsheet system are shown. The more obvious way to do it is shown on the right. The problem is that the lines hit each other, the fine control blocks hit the main sheet, and in general it has problems. The other way rotates the main dual block by 90 degrees and has no such interference issues. It also opens up a large space for the fine tackle so that it does not rub on the mainsheet.

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Soft Line Shackle on a Block

Using a line shackle and stopper loop you can in some cases eliminate hard shackles even from places that would be impossible to do with normal soft shackles. The stopper loop can be "tied" to the clevis pin and the soft shackle integrated into the line for a clean light installation.

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A Better Soft Shackle

Revised 12/12/2011 -- added calculator
I make and use a lot of soft shackles to attach my jib sheets. The normal soft shackle is rather difficult to open and to milk closed. With age, it gets every more difficult to use. The alterniative Kohlhoff style looks a bit insecure although under load it is perfectly secure. This version is a bit of a hybrid with hopefully the best properties of both. The eye is easy to open but can only be opened just enough to fit the stopper knot through it. Almost any slight force will close it quickly. The basic construction is a passthrough eye, a shackle section of about 2 inches, a passthrough lock and then a bury of the other strand into a body section of about 5 1/2 inches, another passthrough and finally a diamond knot.

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Finding Target Boat Speed to Windward


How do we get to the mark fast?

When sailing toward the windward mark I always wondered, should I point high, or should I fall off a little for more speed. Some boats are blessed with instruments that give them these answers. They know how high to point and how fast to go to get them to the mark quickly. My boat is simple. I have a hand held wind meter, a knot meter, and a masthead fly. How can I know what the best point of sail is?

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Try the L-36 Weather and Tide Page Now!

Enter your "CITY, ST" or 5 digit zipcode here :

Examples of valid inputs: "San Francisco, CA" "Golden Gate" "Balboa" "Cow Island" "94301"
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User comments about the Weather and Tide Page from Forums and emails

  • Your site is now my primary weather information. While I really like the way NOAA provides info at their sites, yours is more comprehensive and easier to use
  • Your website is approaching world class. Really Great Job.
  • Keep up the great work, The 4 people I sent the link to loved it.....
  • Been playing with it off and on all week. It's already replaced my usual weather info site. Excellent work.
  • I just wanted to thank you for the terrific weather page. It is my daily go-to page for marine weather. I sail a pair of boats on SF Bay and out of Santa Cruz, and your web site is really extremely handy. It is far better than the "commercial" sites, which is a real tribute given their budgets and what yours probably is.

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Soft Shackles

This is the introduction to a series of 6 pages that deal with soft shackles. Step by Step instructions on How to make a soft shackle, some Variations, and some detail on the diamond stopper knot, . . These are incredibly strong. I show how they are used, below. Nothing is useful until it has been tested , so check that page out. There is even a Calculator so you can make them come out the length you want. Enjoy the series.

vel To the left is a picture of the soft shackle on the jib clew. The addition of the Velcro keeps the diamond knot in the center of the clew ring where it will stay out of the way of the rigging. These shackles are very strong. I did some testing and it is clear that the sheet with the eye and the soft shackle is much stronger than the sheet with the bowline. In my testing, the line broke at the bowline. You can follow the links above and see how to make them, as well as the testing that I did. I did the testing at 2/3 scale which is a little less than 1/2 the strength. The test at the bottom of the page was done to distruction of a link line made of the same Amsteel thus showing that a soft shackle is stronger than the line it is made from. On the rest of this page, I show how to use a soft shackle.

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Weather Reporting Stations

Enter your location by clicking on a map and the page is set up. All Buoy, Data Stations, and Ships reporting will have their data displayed. The report shows the following:
  • Station Name
  • Distance from your selected location
  • Age of the report in minutes
  • Wind speed in knots
  • Wind Gusts
  • Wind Direction
  • Air Temperature
  • Water Temperature
  • Wave Height in feet
  • Pressure (and change)
  • Dew Point of Visability

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Double Soft Shackle

This double ended soft shackle is the 4th generation of a design that can attach to a pair of eye spliced jib sheets to the clew of a sail very quickly. It is also the 5th version of this generation as improvements were made to make the shackle stronger. In use, the shackle is secure around the jib sheet prior to being "clipped" to the clew. This version is easy to make and has the advantage of a non-constricting hold on the jib sheets. There are links to the previous versions at the bottom of this page

The Shackle


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Main Halyard Soft Shackle Variation

hs_2/h2_2.jpg This soft shackle in integral to the main halyard. It is made from a single line with a combination of knots with a finishing splice. I have tested it to over 1000 pounds using 3/16 Amsteel without slip. While I have not tested it to destruction it is very likely that the shackle is stronger than the line so that the failure would be outside of the shackle area. I base that on the fact that the shackle area is made of either 2 or 4 lines so any loss due to the knots is unlikely to bring the strength below line strength. Of course, a halyard is typically not loaded that high as the application is mainly stretch limited. That said, be sure to do your own testing before using this in any critical application.

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We were happy on Papoose to have won our class but sad that one of our fleet was so badly damaged. Eventide was damaged just before the start by a boat from another class.
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.