Without a way of knowing which satellite passing overhead was the ISS, in the narrow windows each day where you could see them well enough to correctly point a Yagi at one, you'd quickly run out of battery before making a relevant contact. Also the people on the ISS rarely listen or respond, the most used ham equipment on the ISS is basically a glorified repeater so you'd also have to get above the pileup of all the satellite chasers just trying to log contacts.
Without a way of knowing which satellite passing overhead was the ISS, in the narrow windows each day where you could see them well enough to correctly point a Yagi at one, you'd quickly run out of battery before making a relevant contact. Also the people on the ISS rarely listen or respond, the most used ham equipment on the ISS is basically a glorified repeater so you'd also have to get above the pileup of all the satellite chasers just trying to log contacts.