I recently purchased a used Tracker Grizzly 1754 boat with a 75 hp motor. The boat appears to have been left in salt water at one point, because there appears to have been some barnacles on the rear of the hull. There are circles on the hull. I power washed the area but it is not smooth to the touch. I realized the drag issue but will this damage the hull in anyway? Do I need to sand the hull? It is on a trailer and with the big engine and the weight of the boat I'm not sure how to tackle this other than lying underneath and trying to sand it etc, which would still leave the part resting on the bunks untouched. Any advice would be appreciated. Thanks