In a small bowl, dissolve yeast in 1/2 cup warm water. Let stand until creamy, about 10 minutes.
In a large bowl, beat together the yeast mixture, eggs, pineapple juice, 1/2 cup water, sugar, ginger, vanilla, and melted butter. Gradually stir in flour until a stiff batter is formed. Cover with a damp cloth and let rise in a warm place for 1 hour.
Deflate the dough and turn it out onto a well floured surface. Divide the dough into three equal pieces and form into round loaves. Place the loaves into three lightly greased round cake pans. Cover the loaves with a damp cloth and let rise until doubled in volume, about 40 minutes. Meanwhile, preheat oven to 350 degrees F (175 degrees C).
Bake in preheated oven for 25 to 30 minutes, or until bottom of a loaf sounds hollow when tapped.