I shaved adult 500 lb off from scraping the 30 years of bottom paint off. Scraped it all by hand with a 4" scraper collected all the chips in a tarp. After that just for the heck of it I weighed them it was just under 500 lb. It came out great and I have noticed a difference on cruse speed about 1knot. Not sure of that is from the weight or smoother bottom.