Ships question, used or not?

I just started reading the novel few days ago transitioning from the manhua and I am in about chapter 218. I have just a question for now. Why did the Alycryans did not use the boats? I recall they had thousands of boats on the coast but I don't understand why they just don't use it from the beggining? i got more or less the part of the underground tunnels and portals but what is the point the of so many boats if they don't use them?