Hello John,

As was stated in a previous reply, the boat will tack very well at 1.5 knots and above. Below that speed, the yankee should be back winded to help the bow get through the wind which will work at even at a near standstill. The rudder will cause some drag but it really does not act as a brake if you consider the dynamics of the turn and water flow past the rudder. It would only be a brake if the boat did not enter a turn. Adjusting the main is not really necessary prior to the tack even if you have to fall off a bit to gain some speed. Hard over briskly on the rudder, don't release your working jib sheet too soon and let it backwind slightly at lower speeds. 

I run the standard yankee on a roller furling with a boomed staysail and really have no experience with a large Genoa on the boat so you may consider that when evaluating my advice.

Werner

Don't despair. I couldn't get Rhapsody to tack for me either when we were new together.