I have 1 700lb bag and 2 540lb bags and i throw 700 across back with 2 540's on surf side corner for surfing,works great and becuase i have no other sacs usually anyone extra sits up front as i have no weight up there although not as critical in DD with motor weight more towards the front anyways. As for the sand, GOOD luck on that one. Lets ee pics if possible. My rubrail is about 2-3 inches only above water when running like this,i wouldn't want more ,TO BE SAFE.