The problem is not the shipbuilder's faith, but rather the shipbuilder putting his faith before the lives of others. Faith isn't intrinsically bad, but the places faith might take you can be bad (or good).

A better example for discussion, I believe, would be that of a Christian Scientist who does not believe in medical intervention. When he becomes sick, it is fine to deny medical treatment. If this person denies medical treatment for his sick child, that may be a different story.