Talk:SailTimer

Comments and Responses

SailTimer is a technology for sailboat navigation, which calculates optimal tracking angles, distances and times.

Sailtimer looks like an iphone app. Completely non-notable, and the description shows a basic lack of understanding of navigation under sail. This reads as an advertisement for a commercial product.

No, this is a geometric method, not an app. It can be implemented as an app, but it can (and has been) implemented in lots of other forms as well. You could even work out the SailTimer method of evaluating polar speeds and tacking distances by hand with pencil and paper if you wanted to. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

Seafarers have had a dilemma for as long as sailboats could use lift to sail upwind.[1][2] Should you head off the wind more, to get more speed (but at a longer distance)? Or should you sail upwind more, to lessen the distance (but at slower speed)?

Seafarers have long known how to determine best upwind VMG.

The point of this innovative new method is that it is different than VMG (Velocity Made Good), and improves on it. For example, when sailing upwind on a tack with a constant speed and heading, VMG decreases towards 0 (and even into negative numbers) all by itself. That is a poor measure of velocity. In LORAN and later in GPS, VMG was designed for aircraft, powerboats and vehicles -- all of which travel in a direct line to their destination. VMG was not intended to be used with sailboat tacks, and it is mathematically incorrect to do so. The results are meaningless, which appears to why the major GPS manufacturers blank out ETA when you stay on a tack for too long (since they use VMG in calculating ETA). 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

Modern sailboats use tacking angle target tables, polar plots, instruments that compensate for leeway, figure in apparent wind etc and interface with sophisticated chart plotting and weather routing software.

Yes, and adding the SailTimer method improves those. For example, no "modern" GPS chartplotters from any manufacturer accounts for the tacking distances of a sailboat when calculating ETA. GPS's can easily determine the distance from the current position to a waypoint, or the distances along two tacks. But that is not a method that they use. That information (as in the SailTimer method) should be available on modern sailboats. As the article notes, the SailTimer method evaluates the exact tacking distances and boat speed on different sailing angles to determine the optimal tacks and the Tacking Time to Destination. The information that this is possible should be in the public domain. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

SailTimer evaluates tacking distances and boat speeds on different points of sail to determine optimal tacking headings. During the original development of the SailTimer software in 2005-2006,[8] the term TTD (tm) was coined for "Tacking Time to Destination".

Original research. In-house re-definition of terminology.

If the destination is upwind but the sailboat goes fastest heading away from this direction, this poses a significant problem: how to choose tack headings with the best tradeoff between maximimizing speed and minimizing distance.

Simply plotting upwind optimum tacking angles (determined how?) does not in any way constitute finding an optimum course. If sailtimer assumes invariant wind, ANY combination of tacks using target upwind angles will result in the same "performance" and same eta.

There seems to be a lack of understanding of the SailTimer method in the above comment. The SailTimer calculations find the tacks that allow the boat to arrive earliest. That is defined to be the optimal tacking angles. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

Given the widespread growth of smartphones, a version of SailTimer[12] is available from the App Store (iOS) for iPhone, iPod and iPad tablets.[13]

Advertising

No; it would be difficult to explain any technological product without making reference to where it is implemented. For example, the GPS entry mentions the companies Garmin and Trimble, and shows a picture of a Magellan GPS. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

SailTimer also runs on a dedicated handheld device called The Sailing GPS.[14] An artificial intelligence algorithm allows it to learn the polar plots for an individual sailboat, which it then uses for making decisions on the optimal tacking route and Tacking Time to Destination.

Not only is this advertising, but it's advertising a non-existent product. Put aside the idea that the data available to the product with the wireless masthead sensor (apparent wind, speed over ground) are not particularly suitable to build a polar diagram from.

That is an assertion, which is not correct. As noted in the Wikipedia:Talk page guidelines, "Article talk pages should not be used by editors as platforms for their personal views on a subject." In any case, the fact of the matter is that polar plots can indeed be learned by storing wind speed, wind angle and boat speed; that is the data that is displayed in a polar plot graph. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

The claim of artificial intelligence is unsupported. If "Sailing GPS"+sensor uses a polar table to determine tacking angles, how does SailTimer do it? Without performance data for the boat, is it just plotting a right angle?

This appears to be another comment that is criticizing the article without any basis for doing so. The reviewer is asking questions about support for their own assertion.

As point of clarification though, the SailTimer method is a novel technique, not a particular product. This innovative technique is based on using polar data, wind speed and direction and tacking distances to determine the optimal tacks and the Tacking Time to Destination. This method is based on finding the optimal tradeoff between boat speed and sailing distance. It does not simply use tacking angles or right angles.

The editor actually seems to be referring to a particular implementation of the SailTimer method that is running in an app for iPad/iPhone. That app does in fact do what the editor is questioning: it uses polar plot data, and beginning in 2012, subsequent versions of the app had the ability to learn custom polar data for individual sailboats.

The ability to learn data in a particular situation and make decisions about the best course to take in response (which is what the SailTimer calculations do), is in fact a good example of artificial intelligence. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

Unless considerable changes can be made explaining why an iphone app is as significant a development in navigation technology as the astrolabe and chip log this article should be removed. As is, it should never have passed afc. 184.175.17.118 (talk) 16:17, 26 March 2012 (UTC)

The article is about a geometric method that can be implemented in many ways. It can be worked out by hand (which would be laborious and too slow to be practical while under sail). Or it can be worked out using software on a variety of different platforms, from weather routing programs, to GPS chartplotters, to handheld GPS, to mobile devices. The commenter has mis-understood that this is indeed a technology, and an important improvement in sailboat navigation over previous methods. 24.138.79.106 (talk) 17:17, 21 October 2012 (UTC)

References