How many messengers were sent to Noah's people?
Let us look at Noble Verse 25:37 "And the people of Noah,- when they rejected the apostles, We drowned them, and We made them as a Sign for mankind; and We have prepared for (all) wrong-doers a grievous Penalty;-"
Let us look at Noble Verse 26:105 "The people of Noah rejected the apostles."
Let us look at Noble Verse 21:76 "(Remember) Noah, when he cried (to Us) aforetime: We listened to his (prayer) and delivered him and his family from great distress."
Let us look at Noble Verse 37:77 "And made his progeny to endure (on this earth);"
For Noble Verse 25:37 and 26:105 above, the apostles before Noah peace be upon him were Abraham (see 19:46), Shuayb (11:91), and Salih (11:61-66) peace be upon all of them.
Mr. Katz wrote: "Were the other messengers drowned as well?"
The answer is, no they did not drown as well. Allah Almighty drowned the people of Noah at the time of Prophet Noah peace be upon him. Allah Almighty said in 25:37 that since the people of Noah insisted on rejected Allah's message from the previous revelations sent to them by Abraham, Shuayb and Salih, and on top of that still rejecting the revelation that came to Noah, then it was time for them to all die and vanish.
Allah Almighty gave the people whom he drowned plenty of revelations and apostles to direct them to the right path of Allah Almighty, but these people kept failing and failing to accept the truth. Their time had ended when Noah came with the last revelation of Allah Almighty to them.
As for Noble Verses 21:76 and 37:77 above, please visit The people of Noah to see their explanation and the response to the anti-Islamic questions and critisisms.