Does anyone know the name of a late 70's / early 80's fantasy movie where a boy is on a boat and he stabs through the floor of the boat and it turns out that the boat is strapped to the head of a giant. The giant then submerges out of the water and begins walking on land. This was the only vague memory I had of the movie as a child and I cannot remember anything else except that it was a disturbing movie for children??
