During the Exodus, why didn't Moses just magically build boats instead of the Jews walking through the desert?

When the Jews escaped from Egypt they had nothing as they were slaves for 400 years underr Pharoah. Also "God" had punished the Jews in there journey, by making it a forty year trek. This way the old generaton would die out leaving the new generation to enter Israel. This is how its said in the Torah, not sayin i belive in it...