I remember seeing a movie as a young lad in the mid to early 90’s. It was about 2 Giant troll monsters, one was good and one was bad. In one of the earliest scenes of the movie there is an over head shot of a boat out in the ocean with a few people on it. As the camera pans back you can see a giant creature lurking below. It then lunges up and eats the entire boat whole. If I remember correctly a group of people raise or know of another troll that is good that they have fight against the bad troll. I’m pretty sure the movie was in color. I can’t remember much more than that. It was probably made in the 80’s I would guess.