Tuesday, April21, 2015 L-36.com

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Leeway

This article discusses leeway and its influence on measurements of the True Wind Direction using standard sailboat instruments. In particular I will addresses the notion that is presented in other sites online that leeway can be added to apparent wind angle. I will show that this is not the case and discuss the implications of leeway on measurement accuracy. Along the way I will explain leeway.

Sailboats can sail upwind because the net balance of all forces point more forward than sideways. The diagram below shows those forces. The blue arrow is the net force of the wind on the boat. This force can be resolved into a lift and drag vector. It can also be resolved into a heading and leeway vector. The heading vector is the forward force on the boat that moves us forward. The leeway vector tries to move us sideways and the boat needs to develop a force equal to that force and hopefully can do that and yet still have the boat go mostly forward. That is the job of the keel.
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StartLine Racing on Android

NEW StartLine4 now has a Pebble app? Just search StartLine in the Pebble app store.
NEW StartLine5 will now interaface to onboard instruments over Blutooth using the
L-36.com Race Box that can be easioly built with $100 to 200 in parts depending on how fancy you want to get. Contact me for details. You don't even need to know how to solder!
Overview
StartLine is a very powerful racing app, second only to Expedition. Unlike Expedition, it is free. However, I limit the number users because along with the app comes a huge amount of support both to get the full potential out of the app but also to help users improve users race results. Users must agree to contribute to the StartLine community by providing feedback on results or actually participating in the ongoing development which may just be to ask for new features. You must be serious about racing and commit to put in the time to learn the app. It will improve your race results as it has for the other users. It is a small community but already has a podium finish in a prestigious regatta. Read this somewhat outdated manual below and let me know if you are interested in joining the StartLine team.
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Custom Marine Display

I have been looking for a display that will work in a marine environment that I can write arbitrary text to. I signed up for a Earl Backpack Tablet but it looks like it is vapor ware so I got my $300 back. I next considered using the TackTick Remote as the manual says that it can display 6 custom sentences. I bought it but could not get it to work. After a month of trying to get an answer Raymarine said that it would not work due to a software change and that their solution was to change the manual so that it would no longer say it works. Sucks. My next attempt was to look for a company that made a NMEA-0183 display and see if it could display custom $P nmea sentences...
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Knife Review -- one year later

It has been a year since I wrote the knives on a boat review. It was really a review mostly of every day carny or EDC knives with one specifically marine knife with a marlin spike. I have lived with these knives and find my favorites to be a little different than my first impressions. I still like all these knives very much but the question is, which ones do I end up using and what do I use them for. For this review, I have added short 15 second videos of the knives opening and closing so you can get a better picture of how they work. I also added a discussion on two knives I bought recently. One I returned the same day and the other I am not really sure what I am going to do with but it is so nice I just had to get it. It is a knife I have coveted since the first time I saw someone with one.
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Unassisted Mast Climbing Update

In the article on Unassisted Mast Climbing I prefer the modified method but mention that the GriGri method is easier to use. There are two things I did not like about the GriGri method 1) It requires re-rigging the setup at the top of the mast. That is really a most unpleasant experience. 2) The descent, while quick and easy, it jerky and can be frightening and if you panic, can be really scary. I have developed a new method for the re-rigging and descent that solves the second complaint but you still need to do the re-rigging. This article presents that technique and reviews the GriGri method.

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Oh the horors of having tape pull up the paint below

Seemed like a simple enough project to paint the deck on my boat. Add some non-skid and repair several years of little cracks where the old non-skid was coming off. It turned into the project from hell when the masking tape pulled off the paint below. In spots it did not pull anything off. In spots it pulled off my fresh paint. In other spots it pulled off 10 years of paint leaving rather deep ridges. In one spot it pulled off all the paint, 60 years worth, all the way to the base cloth. This was a low stick tape. It was not as low stick as the tape I once used so I started looking for more of that tape. I could not find it but I did find a list of tapes and how sticky they are. This is not very easy to find so I thought I would share the results of the several hours I spent online finding this information.

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GoPro Fogging

The promise of videos of my sailing was too good to pass up so I bought a GoPro Hero 2 shortly after they came out. I did get some good videos but all too often the images that came back would be fogged up. It got to the point that I just didn't want to bother to put the camera on the boat because I knew the videos would be fogged. I tried many things to prevent this but nothing worked until this last time.

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My GoPro will not Turn ON

My Gopro Hero 2 would not turn on. I had done nothing to it since last using it except letting it sit. I knew the battery was charged and the SD card was good because I have two GoPros. The battery worked in the other camera as did the SD card. Of course, if your GoPro does not turn on, check the battery. The first test is to remove the battery and SD card and plug in a charger using the USB cable. The red light on the front blinked and when I pressed the power switch the red light went out and the unit did not turn on. The red light flashing proved that the USB cable was good and the fact that it did not turn on proved I had a serious problem.

The solution is to update the firmware using GoPro Studio. But you must have the camera on to do this.

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Racing with a Whisker Pole

Most sailors have whisker poles to hold a jib out to weather. Not that many use them in racing as a spinnaker is the preferred sail for racing downwind. But not everyone wants to use a spinnaker and some of us race in classes that do not allow spinnakers. Over the years we on Papoose have tried to prefect using a whisker pole while racing.

What I am about to discuss conflicts with the instructions you will find for using a whisker pole. The conventional methods assume you are not racing and are not helpful if you are. Cursers can furl the jib, set the pole, and then unfurl the jib to the pole. To remove the pole, they can furl the jib back up. A racer would not want to do this even if they could but there is no reason a cruiser has to either if you know some of the tricks discussed in this article.
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Bacon Sails is Back

L-36.com is happy to announce that Bacon Sails is now listed in the Used Sails Search application. You can now search from the thousands of used sails that Bacon and other vendors, North, Minneys, Pineapple, have in stock. The inventory is updated every evening. Search results list just sails that stand a good chance of fitting your specific boat. L-36.com has listings for thousands of different boats listed by boat name. This is an excellent way to quickly see if any used sails are out there to improve your sailing experience.
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Race Committee Timer

Race Committee Timer, RCTimer, is an Android application designed for race committees to do starts for sailing regattas. The timer can be set to a count down time, for example 5 minutes. It can also be set to a specific start time, for example 12:30. A sequence can be set so that multiple fleets can be timed in rotation, for example a start every 15 minutes. The timer can be started or stopped and minutes can be added. There is a reference page with signal flags and a lock button. The latest feature is that the app will now talk or sound a horn blast. Sounds can be programmed to occur at any count down time and anything can be said. A simple text file defines what is said or when the horns are sounded. The app is free. A version without sound is on the Google Play store under RCTimer.
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Hybrid Soft Halyard Shackle

Yet another way to make a soft halyard shackle out of Amsteel. This is one that I am using on my boat. The advantage is that the hybrid knot gives approximately full line strength but only extends a couple of inches so that the short splice will not end up making the line that goes into the sheaves fatter. This prevents extra wear in thinner halyard sheaves. The knot provides the locking action which removes most of the load from the splice. The short bury distributes the load enough so that not all of the load in on the knot. The result has been tested to near full line strength. This knot is one of just a few that do not slip in Amsteel. The knot is strong and the splice prevents slippage.
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Block Mechanical Advantage

This is the first part of a two part tutorial on mechanical systems made from blocks and line. I will explore the mechanical advantage of various systems, and shows the general principles on how to set these systems up, including how to thread the line through the blocks, or reeve them. It will go from 1:1 to 6:1 with simple systems and up to 24:1 with cascaded systems. The second part will explore some more unusual systems.
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High Strength Soft Shackle

Recient work by Brion Toss, Evans Starzinger, and myself has led to the development of a high strength soft shackle that Evens has tested to 230% of line strength. The secret to this added strength in primarily an increase in the strength of the knot, the weak point in conventional soft shackles. I should point out that Evans testing shows conventional soft shackles, with diamond knots, test at 170% of line strength, considerable above the "higher than line strength" number I have been using. While these two statements are consistant, the more percise number is considerably higher and higher than the testing I had done at NE Rope.
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Disclaimer:
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 L-36.com. 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 L-36.com 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.