Insanely Fun DIY Science Experiments at Home with Physics Girl

The boat would bob. While still in ice form and in your hands the weight of the ice would act on your hand and in turn through you on the boat. When it drips off the water drop would be I'm mid air, therefore no longer exerting a force on your hand and by extension the boat. At the moment of impact with the bottom of the boat it's weight would once again exert a downward force on the boat this time directly on the boat itself.