If you don 't know what the previous owner used on the bottom of the boat, how do you know if the stuff you 're about to put on is compatible?

Last year I put some expensive Micron 66 on the bottom of Toodle-oo! It did well, I was happy when she was hauled last year... but... in reviewing it this Spring, I see that much of the bottom paint is now flaking off. Is this because of an incompatible previous coat, or perhaps because the Micron 66 has dried out over the winter and is now flaking. (Yes, I wish I had paid closer attention last year when she came out of the water...)

If paint is incompatible with the previous layer, does it show that fact immediately upon application?

Thanks,

Bill Balme