Cleaning Lund Tyee Hull

[Hicangler]

I have a 1975 Lund Tyee that was kept in a marina a good part of the summer that has heavy scaling/calcification on the hull. Tried Boat Drip Exterior which was fantastic for removing water spots and shining above the rub rail. Below is where the problem is. What will work to restore the hull but not harm the boat? I’m told not to use anything acid-based. Thanks!