Can you guess this science riddle?

Add a brick to a five gallon pail filled half way with water and I think the water level in the bucket will rise.If you have a brick on a boat with you and you throw the brick in the water it probably will not change the water level because the weight of the brick will make the boat take up more area in the lake so throwing the rock in the lake will not change the water level due to the weight of the rock is still in /on the lake. Or is that true? Is the correlation between the weight of the rock compared to its displacement/volume change accurate? Apples and oranges...