New tech: The Sailing GPS

[Indulgence]

Saw this in Pacific Yachting magazine. Supposed to be $300. It calculates the optimum times to tack based on
your speed, destination, etc.

link here: http://www.thesailinggps.com/index.html

From the manufacturers web page.

How Does It Work?

When heading on some angle into the wind, sailors face the longstanding seafarer's dilemma of how close to the wind to sail.
Do you pinch close to the wind to shorten your distance, even with a loss in speed?
Or head off the wind to pick up speed (but increasing distance to travel)?

You might think that modern electronics would have provided a solution for this long-standing navigation problem.
But even if you spend $1000 or more on a GPS or chartplotter from any manufacturer,
as soon as you start tacking upwind the ETA goes blank as if you are off-course.
Click here to find out why.


Fortunately, The Sailing GPS solves these problems.

Whether you are racing, long-distance cruising or pond sailing on a Sunday afternoon,
you can see the optimal tacking route at a glance.

Just enter the directions of the wind and your destination with two buttons and the optimal tacking angles are displayed.
Enter your boat length, distance to destination and wind speed, and we can now calculate your Tacking Time to Destination (tm)
as well as the distances on each tacking leg.

Even experienced sailors have a difficult time picking the optimal sailing angle, especially when you are not heading directly upwind.
The Sailing GPS provides a simple solution for this longstanding problem.

[Duane Dunn, Allegro]

Actually you can get useful sailing info from any marine GPS. Just set a waypoint at where you are trying to get to and then make sure you GPS is configured to display VMG (velocity made good). That's what you want instead of ETA. As you tack off to the side of a direct course your VMG will drop. Sail so you get the highest VMG and you will be choosing the best course to make the mark.

[Love MACs]

Thanks Duane I learned something else from this site, that I didn't know. Just love to pick up new tips

Allan

[markdartist]

Whether to us VMG when racing to a mark is a common question in sailboat racing and the correct answer is suprising. VMG alone, to a mark, will not get you there quickest. Check out this link for VMG to wind to understand why sailors need to consider wind direction for optimum (quickest) speed to a destination. Even with a destination dead down wind, a zig zag path, in most sailboats, will get your there sooner than a direct course.

http://knol.google.com/k/why-vmg-matters#

I gotta checkout the device mentioned in Indulgence's post. Sounds pretty cool and might help win some races!

[Indepth Navigation]

I just wanted to add to Duane's observation that " As you tack off to the side of a direct course your VMG will drop." It is important to remember that this means that it is not mathematically correct to use Velocity Made Good as a measure of velocity. For example, if VMG is 6 knots and you have 6 nautical miles to go, it is not correct to conclude that you will be there in 1 hour, for the reason that Duane says: VMG deflates on its own the longer you stay on a tack heading away from the rhumb line. Therefore VMG is not safe to use in calculations.

Duane also notes that sailors shouldn't use ETA. That is a major safety issue that all sailors (and sailing schools) should be aware of. This is the reason that the SailTimer software and The Sailing GPS were developed. You don't want to travel blindly, with only vague guesstimates about how long it might take you to get to your waypoint. With The Sailing GPS, it instantly displays the correct Tacking Time to Destination (tm) under the current conditions.

If anyone here is wanting a low-cost version of SailTimer to try out on their iPhone or iPod Touch (and soon on the new iPad!), you can get the iTunes link at the website below.
- Craig

http://www.IndepthNavigation.com