# VMG--by feel or by GPS?



## jnorten (Aug 18, 2009)

During a typical weekly around the buoys race, does VMG info from a GPS offer significant advantage compared to deciding the preferred tack "by feel"?

Last week, we didn't have VMG info. The weather was clear--we saw the weather mark. We could see how the start/finish line was oriented relative to the wind and the weather mark. And, "by feel" we decided which tack would be preferred as we started and sailed to the weather mark.

So, what are the pros and cons of trusting the VMG versus doing it "by feel"?


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## PaulinVictoria (Aug 23, 2009)

VMG via GPS gives you accurate, empirical data. What it can't do is see where the puffs on the water are, where that little river of current will give you a boost etc., that's where the feel comes in. Combine the two whenever possible.


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## Cap'n Russ (Jul 15, 2013)

I've raced on several boats where the skipper/helmsman was buried in his iPad and failed to hold the preferred course so we lost any "advantage" we were getting from the GPS data. During one race, rain forced the skipper to stow the iPad and we actually did better without it. Lesson here is to have the navigator/tactician reference the plotter and the helmsman sail the given course and observe the wind/current interactions. It's gotta be a good balance of the two to be successful.


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## CalebD (Jan 11, 2008)

Before GPS people always raced "by feel". 
I agree that a good balance between the two is probably best.
Some are over reliant on GPS.


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## emc_ret (Jun 24, 2014)

A basic rule of thumb for sailboat racing is to "sail the longer tack first". This could be restated as "sail the tack on which your boat is pointed closer to the mark". Your VMG will be higher when you are on the tack which points closer to the mark. Higher VMG is a result of choosing the correct tack.

Where VMG read from GPS is useful is in the pinch / foot discussion going upwind. It is easy to look at VMG and then pinch or foot and look at VMG again to see if the change in mode increases VMG.


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