The Liberty is a matter more than one fast fly-by. It was a sustained attack. I suggest you read through a webpage which draws on the firsthand accounts of the US servicemen who were there. An excerpt giving a summary account is given below. For all the intelligence the Israelis are capable of among Arabs and on American soil, I find it incredible to believe that they did not know the USS Liberty was in the area.
“On 8 June 1967 the electronic intelligence ship USS Liberty (AGTR-5) was on station in international waters 13 miles off the Sinai Peninsula in the eastern Mediterranean. The Arab-Israeli War had wound down, the air was clear, and the seas were light. What happened early that Thursday afternoon is well known. Without warning, a furious attack on the ship commenced from Israeli Mirage and Mystere jets, followed by Ayah-class motor torpedo boats (MTBs). Employed were rockets, napalm, quick-firing 30-mm and 40-mm cannon, .50-caliber machine guns, and torpedoes. Four unshielded .50-caliber machine guns were the Liberty's only defense. The one Israeli torpedo hit of five launched left a yawning 40-foot hole in the hull, devastating the cryptological spaces below decks and killing 25 U.S. National Security Agency (NSA) technicians instantly.”
I've not only been through the website top to bottom, I've read two books on the subject, seen at least that many TV documentaries, and beat this dead horse into jerky here and at Liberty Post.
The crews of the torpedo boats were in no better position to make a correct identification than the pilots. I have practical experience in teaching threat identification as an Army Intelligence officer. Compared to ships (excluding major warships like CV's and BB's), identifying tanks and aircraft is a piece of cake, and you'd be suprised how hard it is to teach soldiers to properly do it even in a classroom environment. Put them in a real threat situation and they tend to screw it up everytime.
In fact, in the first gulf war, fratricide was so bad that the Army practically gave up trying to teach soldiers threat identification through vehicle classification. That's why all of the vehicles had those zebra striped panels on them this time around. Anything without an ID panel gets shot--period.
Lastly, there is the adrenaline factor. In any given situation, once a shot is fired, all bets are off and everyone starts shooting at any imagined target.
I proved this point during an ftx by going out to the perimeter and firing my M-16 out into the woods beyond our defenseive line. It was broad daylight, no threat in sight. Within 15 seconds every weapon in the batallion was engaged firing at nothing. Later I repeated the demonstration by firing on a vehicle clearly marked as "friendly" (big visible "Blue Force" ID panels). Same thing happened. This whole thing was done to prove a point a point about fire discipline.
Now, if this is the way trained soldiers react in peace time, firing blanks, how do you think they will react when they are at war and have been sent to attack a ship they have been told is firing at their troops?
Even police have this problem. Remember that kid in NY that was blasted 19 times because he reached for his wallet? One cop misinterpreted what the guy was doing and as soon as he fired one shot, he and his partners emptied their clips.
My take on what happened is that the Liberty was mistaken for the Egyptian ship that the Isreali pilots and sailors were sent to intercept, and predisposed to identify as such. A horrible mistake abetted by Johnson's ordering the ship into an area we had been warned against entering.
The Isrealis had nothing to gain and everything to lose by deliberately attacking a U.S. warship.
The Liberty's crew members and their family's are angry over what happened, justly so, but their anger IMHO is mis-directed.
"In war more than anywhere else in the world things happen differently from what we had expected, and look differently when near from what they did at a distance." - Clausewitz, On War, 1832.
"War is the province of uncertainty; three fourths of the things on which war is based lie hidden in the fog of greater or less uncertainty." - Clausewitz, On War, 1832.
"It is my opinion that coordination is a very much-misused word and its accomplishment is difficult." - General George S. Patton, Jr., War As I Knew It. 1947.
"In... a close fight a soldier has not time to change his mind." - General George S. Patton, Jr. November 22, 1942.