Slice fresh pineapples into chunks. Drain well the syrup if using canned pineapple chunks.
Place drained pineapples chunks in a blender and pulse for 2-3 minutes or until smoothie-like.
Pour in the pineapple juice, orange juice, rums and lime juice into a pitcher. Gently stir.
Pour punch mixture into serving glasses filled with ice. And then slowly pour in a splash of grenadine.
Most of the commonly used rums in a rum punch: – White Rum – Spiced Rum – Coconut Rum – Flavored rum (pineapple, mango, etc.) – Dark rum