Yes, he's very intelligent, and he knows his facts.
Watch the debate on you tube that he did a while ago against Bill Nye. Ken Ham clearly won!
I think that he and Kent Hovind are both very intelligent. You can't truthfully watch their debates and seminars, and not think, "wow...He won hands down," or, "WOW, what amazing facts...!!"
Listen, you don't have to agree with the man, but he's built a very successful company and has constructed a well rounded theory, for the most part. He's not stupid just because he doesn't fit in with mainstream science, or because he is alt-science. Even if his theories are dumb, that doesn't make him unintelligent.
Smart people can be wrong all the time. I didn't agree with what he was saying in his debate with Bill Bye, but that's not because he's too dumb to convince me. I believe he's a very smart, articulate man, who has applied these traits to validate his faith for himself and for others.
He's spent his life simply doing that: gaining intelligence. He's done tons of writing, research, and debates. He is very intelligent, and though I don't completely agree with him, I don't completely agree with anyone. I will say that his presentations and writing are dull, and I haven't seen much of his work.
He's smart enough to be manipulative of the evidence. To be untruthful in his presentation of the facts, and to be willfully ignorant of reality. He's smart enough to make a business out of people's beliefs, and profit off of their willingness to take him at his word.
Unfortunately, he resists progress. He maintains an impossible account of reality and, despite abundant evidence, refuses to change his mind out of sheer close-minded dogma. Whether intentional or not, he undermines scientific literacy and stunts young peoples minds into believing lies rather than the truth.
All of this is said completely aside from his faith. I have no qualms about him believing in any particular religion. I will not, however, allow him to spread the lies that the religion brings forth with it. (Whether these lies are inherent within the text itself is beside the point)
At the end of the day, he's a young earth creationist. This severely limits any respectable mind from putting stock into his words.
Excellent question, by the way!
It is impossible to be an intelligent creationist. We have over 150 years of evidence confirming evolutionary theory. Ken Ham's position requires the blanket denial of biology, physics, geology, much of philosophy, and even the more sophisticated forms of theology. If everyone thought the way he does, we would lose all of science, much of medicine, much of engineering, agriculture, industry. I would argue that basic scientific literacy (that's not to say the details of science--just basic literacy) is prerequisite for being considered intelligent. Because Ham denies science, he fails to meet the criteria.
On the other hand, it's possible that he actually does understand all of this and is just lying about everything to make money. I don't think that's true, but it is an alternative possibility. In that case, he may be intelligent, but is dishonest.
In either case, we shouldn't listen to him.