What are "Alonim"?
Rashi: It is a barren species of tree (oak).
Radak: It is chestnut; and so Yonason translates.
What are "Mishotayich"?
Rashi: They are oars ? they are wide at the end. They are used to conduct the boat. Radak ? this is like "Kol Tofesei Mashot" (29).
What is "Karshech"?
Rashi: It is the rudder, a wide beam at the other end of the boat, opposite the mast at its head. It is used to turn the boat in all directions, and direct it [to the desired direction]. The captain holds it.
Radak: It is the beam of the boat. Normally, there is not only one! It refers to the beams of the tower at the head of the boat.
Was it of "Shen Bas Ashurim"?!
Rashi: It can only be of wood! It is as if Bas Ashurim is one word, like "Tidhar u'S'ashur" (Yeshayah 41:19). Targum Yonasan of both of these (Bas Ashurim and Se'ashur) is Eshkero'in (box wood). The leader of Tzor is compared to a rudder of Eshkero'in, and covered with ivory (elephant tusks) via nails, for beauty and strength; the cover will not fall off. So Yonason explains.
Radak: Yes. In other boats, it is made of beams of good wood. In boats of Tzor, they made it of ivory for grandeur and beauty. It is called Bas Ashurim, for the congregation of Ashur made them for you. They brought ivory from the islands of Kitiyim, where elephants are found. They make beams and Kelim from it. It is called Shen, for they make it nice from the teeth (tusks).
Malbim: [The elephant] was born in Ashur, and brought from the islands of Kitiyim.
It is written Kitim, and we pronounce it Kitiyim?
Radak: The pronunciation has a Yud for Yachas (of Kit), and a Yud for plural, like "Elokei ha'Ivriyim" (Shemos 3:18).