In my experience, the traveler is one of the least used and poorly understood main sail control devices. I wasn’t taught anything about it’s use during my training with Club Nautique. In fact, it wasn’t until I acquired Skiron that I began to read about and experiment with the device.
As mentioned in another post, the mainsheet is the principal regulator of mainsail twist on all points of sail except those more off wind than say a beam reach. When sailing upwind of a beam reach I first adjust mainsail twist with the mainsheet when the traveler is midline. Then, I’m ready to employ the traveler. Here are some basics to keep in mind and try.
I employ the traveler to move the boom, thus changing the angle of the mainsail to the wind, to set a point of sail varying from close-hauled to a near beam reach. Previously, I’d just let out or pull in the mainsheet. This approach helps prevent stalling the main if the mainsheet is tensioned too much or de powering when the sheet is detensioned leading to too much twist.
The traveler can be used to bring a mainsail towards the midline, windward, in light winds in order to power up the main.
The traveler can be relaxed to bring a mainsail to leeward in heavy winds thus de powering the sail.
The traveler can be used to respond to a gust. It can be used to decrease weather helm by allowing the sail to go towards the leeward side of the vessel.
When sailing off the wind I keep the traveler to the leeward side of the track. Usually, it’s all the way over on broad or deep broad reaches.
Try some of these basics to get a feel for it. I believe that you might pick up a knot or two in your upwind points of sail if you properly combine the use of the mainsheet and traveler.