The IHH are a valued part of the flotilla but they are the whole flotilla, they are just one part. the rest of the 12/13 ships will sail anyway, no chance the flotilla won't go ahead. Hopefully the IHH, who I respect immensely for their humanitarian work, will be a part of it but who knows?
PLO official: Reports about Abbas' resignation from political life very premature (Haaretz)
from the article: Turkish organization may cancel Gaza flotilla as IDF prepares at sea