Conservapedia is trying to be a Wikipedia alternative - an Internet encyclopedia, from a fundamentalist point of view.

RationalWiki is not, and I'm not sure why you mentioned it. It's not a Wikipedia fork or alternative. It's not even trying to be one, it has completely different goals. The only thing they have in common is the fact that they are both wikis, but there's thousands of those around.

Rationalwiki defers to Wikipedia on some things but writes articles on topics when they think the Wikipedia article doesn't go far enough in a direction they would like. Most rationalwiki articles would be redundant if their goal wasn't to overwrite Wikipedia