A "winch" or a "Windlass"? You'll want quality Stainless Steel bolts fresh or salt water. Determine what the "winch" installation specification are and do that..
You can do the 2D statics loading calculations analysis here: https://www.engineersedge.com/calcul...d-modeling.htm
Also, I would consider the deck loading capability as well. You may need a backing plate to distribute the load and honestly, 2000 # seems excessive unless you has a serious need for something.