Place corn husks in a bowl, cover with boiling water, and soak for about 3 hours. Drain, place on a work surface, and cover with a clean, damp towel.

Combine pineapple, water, and sugar in a saucepan and cook over medium heat until pineapple is very soft, about 7 to 10 minutes. Drain.

Mix masa dough with butter and baking powder in a bowl until well combined. Add cooked pineapple, coconut, and raisins; knead into a smooth dough.

Select 1 wide corn husk or 2 small ones. Spread about 1 tablespoon masa mixture onto the corn husk, filling it up to 2 inches from the bottom and 1/4 inch from the top. Fold sides of husk together, one over the other. Fold the bottom of the husk over the seam of the 2 folded sides. Repeat with remaining husks.

Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Add tamales with the open side up and cook until filling is heated through and separates from the husk, about 45 minutes.