A variation of the overhead cast, known as the double haul, is the final step in increasing line speed and thus adding length to your casts. The faster a fly line moves, the more momentum it has. Greater momentum allows you shoot longer lengths of line. The double haul is used for long casts, over 60 feet, and/or when there’s a lot of wind because greater line speed will overcome either obstacle.
View/open a WORD document here (or on the Members Only, Club Documents page) to read about this technique as presented by Tom Rosenbauer.
In case you would like to see video, check out this (Youtube) 5 min demonstration by Lefty Kreh who gives lots of tips on what NOT to do.
Other interesting articles with titles like, "Dealing with the Wind", "Get Them On, Then In" and "Casting Unruly Rigs" can be found at midcurrent.com