Hmmmm ....
First of all you need to be close hauled before you start your tack. As Matt says, when you're close hauled your mainsheet will be snug, borderline tight. You should have two pieces of magnetic tape taped to your bridles about 18 inches down from the forestay adjuster. (Half inch is best (VHS), Heavy Metal is reputed to be fastest.
) When you're going upwind the windward telltale should point down the back of the mast/sail.
Again as noted above push the tiller over gently at first. The boat is longish and skinny and doesn't have a pivot point (centreboard) in the middle.
Now this is the important part, which I guarantee you're not doing, keep the tiller over and the boat turning when you go across. If you allow the rudders to go straight the boat will stop turning and will end up in irons. Which is what you're experiencing. When the boat is head to wind ease the mainsheet. Four feet when you're learning, maybe only 8 inches when you're a great tacker. Keep the rudder over and the mainsheet eased until the boat is pointing in the right direction, the new upwind, with the (new) upwind telltale pointing down the back of the (other side now) of the sail. Sheet in! Success!
YMMV
Damn I do love this boat!
It's not the bow it's the indian.