In the 4th-century Latin translation of the Hebrew Bible, the Vulgate, St. Jerome rendered yam suph as mare rubrum to designate the Red Sea, and the King James Version of the Bible (1611) also translated yam suph as Red Sea. The translators knew exactly what they were doing.
Indeed, as already confirmed, yam suph means Sea of Reeds, but all the biblical citations imply a Red Sea crossing, not a soggy march through an inland reedy lake, such as Lake Timsah and the Bitter Lakes, a day’s journey from Rameses (q.v.), and two of the modern scholars favorite candidates for the Sea of Reeds.
What lay behind God’s plan in leading Moses and the Israelites in the desert to the Red Sea (as stated in Exodus 13:18)?
Moses began the Exodus from Rameses (modern Qantir) in the Nile Delta and followed the ancient trade route to the head of the Gulf of Aqaba. If you saw Lawrence of Arabia, Aqaba will sound familiar.
But where are we geographically in this account? you’re asking. Well, spread your left forefinger and middle finger as far apart as you can. Your middle finger, pointing northwest, will be the Gulf of Suez, and your forefinger, the Gulf of Aqaba. The dorsum (back) of your hand represents the main body of the Red Sea. The two gulfs are thus projections or extensions of the Red Sea and as such are parts of the Red Sea. In ancient times, the gulfs themselves would also be referred to as the Red Sea. As for Aqaba, it is at the head of the Gulf of Aqaba (near the tip of your index finger).
During the time of the ten plagues visited upon Pharaoh, Moses and Pharaoh were actually sparring. What Moses wanted from Pharaoh was permission to take the Israelites out into the desert three days march from Rameses to sacrifice to the LORD. It was to be three days out and three days back plus one day for offering sacrifice, one week in all. Only Moses, of course, had no intention of returning. He had secured sufficient provisions from Pharaoh to make it to the tip of the Gulf of Aqaba, where he would find plenty of fresh water to be able to continue the journey to Mount Sinai.