from egypt to asmara by sea

hi!
i'm planning to travell down the nile and as i reach the southern border of egypt go east to the red sea cost and take a boat/ sheep/ fairy or whatever that would take me over to asmara (eritrea) by sea.
i cannot enter sudan or saudi arabia because of my israeli citizenship.
does any one have any information about the possibility of doing such a thing????
would appreciate very much any information!!
what's the best place in egypt to take a bout south????
thanks!