And His are the Al-Jawari (ships), the Al-Munsha'at (lofty/constructed)

"And His are the Al-Jawari": These are the ships (al-sufun), the plural of jariya (that which runs). He, Glory be to Him, singled them out as belonging to Him—while He, the Exalted, possesses the dominion of the heavens, the earth, and all that is within them—to indicate that their existence does not remove them from His dominion, Mighty and Majestic is He, as the entirety of their benefit is solely from Him, the Exalted and Majestic.

Abdullah [ibn Mas'ud], Al-Hasan, and Abd al-Warith (narrating from Abu 'Amr) recited it as Al-Jawari with an explicit damma on the ra'. This is because, when the omitted letter [the ya'] was forgotten, they gave the letter preceding the final one the grammatical rule [of the final letter], as in the saying: "It has four beautiful teeth, and four, so all of them are eight."

"The Al-Munsha'at": That is, those that are raised, as Mujahid said, in the sense of ansha'ahu meaning "he raised it." It has also been said: those raised upon the water, though this is weak; and likewise, it has been said: those which are constructed/manufactured.

Al-A'mash, Hamzah, Zayd ibn Ali, Talhah, and Abu Bakr (with a differing report) recited it as Al-Munshi'at with a kasra under the shin, meaning: those that raise their sails, or those that create waves by their running, or those that create movement by advancing and retreating. In all these cases, there is figurative usage. Ibn Abi 'Ablah gave the shin a shaddah. Al-Hasan recited it as Al-Munsha'at (singular), making the attribute singular while indicating the plural of the described noun, like the saying of the Exalted: "Pure spouses" [implying the plural]. He also changed the hamzah into an alif, in the manner of the saying: Verily, the beasts of prey would be calm in their resting places, meaning tahta'u (calm down), and the ta' is for the feminine gender of the attribute, written as a ta' according to its pronunciation in the original.

"In the sea like mountains": That is, like towering mountains. A'lam is the plural of alam, which is a tall mountain.