I can sink a spike with no throws accuratly as far as 13ft. If I just have to hit a board, and it just has to stick, maybe 17-18ft.
Sinking knives, hatchets, etc. Is an entirely different matter. If I can up the force, control the spins, have good form, and have a good release, I can throw infinitly far. As of right now, probably 25ft accuratly and reliable. I don't practice spin throws often though.