I have fitted one by turning my beltsander upside down in a 'workmate' type workstand and carefully rotated the pole to get the taper. Once near the correct size I rubbed chalk on it and offered it up; the marks on the chalk showed the high spots.This was a utility boathook made from dowel. If you are starting from a square piece of timber you will have to eight side it and then sixteen side it and then sand it to its final shape.
I once saw in american magazine a boathook that was made in such a way that it floated upright to ease recovery if dropped overboard. This was a good idea I thought, but hard to figure out the buoyancy issues involved.