Max HP Motor for my boat

Does any one know how to find out what max HP motor my boat is rated for? I have a 1980 Fishermarine 15' with 38" bottom. The plate that has all the info on it is faded and I can't read it.

I would be 15 - 20. 25 is a stretch, but that is what I would have on it.

I have a 9.9 on it now, but would like to get a 25 for larger lakes.

Do you guys think a 25 would be to much for this boat?

No. Mine is 4 inches wider at the bottom (probably closer to 6 inches wider at the top) and it has a 40 (prop rated, so similar to a modern 35). With 3 people in the rig, I can pretty well turn it all the way at WOT. 2 people and I can do almost anything. With me alone, it will try to slide a little bit if I really maneuver with it. Of course, mine isn't the lightest rig for it's size either.

Is their a web site that has spec's for a boats max HP?

Yes. It goes by dimensions. The boat will hold a heck of a lot more than it is rated for. The US Coast Guard has a website with a calculator that you use the length, beam, and transom height, as well as whether or not it is a hard chine/soft chine. It figures that a hull of a certain type, with a certain dimension, will be safe with a certain HP. However, your boat won't fall apart even with a 35 or 40. I run a 1542 with a 40 (modern 35) tiller.