No, a penny cannot react with an aluminum boat to cause it to sink. However, adding enough pennies to an aluminum boat can make it sink due to the increased weight exceeding the boat’s buoyancy and displacement capacity.
and
While pennies can corrode in certain conditions (like saltwater), the reaction with aluminum is slow and minimal. Aluminum is generally more reactive than copper and zinc, so it would preferentially react with the surrounding environment, not the pennies.
Another Hoax taken down.