The oldest Hebrew manuscripts of the Song of the Sea offer very little new material to our translations. This is also true of the Pentateuch in general. There are “orthographic” variants (spelling differences), but there are relatively few translatable variants to be found in the ancient manuscripts of these five books. Even in the case of the oldest manuscript, 4QExodus c, of the ten minor variants listed in its final publication (DJD XII), only one is potentially “translatable”. In Exod. 15:18 the plural noun for “hand” is singular “your hand” (agreeing with the Samaritan Pentateuch), as opposed to the plural “your hands” found in the Massoretic text. Hardly noticeable.
There may have been other ancient Hebrew manuscripts of the Pentateuch that contained more noticeable variants but, if so, they have been lost. The clearest witness to such manuscripts it is to be found in ancient translations of the Pentateuch, especially the Septuagint (Greek) version (aka LXX).
It is best to look for these hidden variants by studying and comparing the Greek text itself (especially in the Göttingen edition of the Septuagint) to the Hebrew of the Massoretic text. However, one might be able to do an initial survey of some of these translatable variants by comparing the standard English translations of the Pentateuch with an English translation of the LXX (e.g., Benton). Benton’s translation is old, uses some archaic language, and does not necessarily reflect the best manuscripts of the LXX; however, here it is.
“15:1 Then say Moses and the children of Israel this song to God, and spoke, saying,
Let us sing to the Lord, for he is very greatly glorified:
horse and rider he has thrown into the sea.
2 He was to me a helper and protector for salvation:
this is my God and I will glorify him;
my father’s God, and I will exalt him.
3 The Lord bringing wars to nought,
the Lord is his name.
4 He has cast the chariots of Pharao and his host into the sea,
the chosen mounted captains: they were swallowed up in the Red Sea.
5 He covered them with the sea:
they sank to the depth like a stone.
6 Thy right hand, O God, has been glorified in strength;
thy right hand, O God, has broken the enemies.
7 And in the abundance of thy glory thou hast broken the adversaries to pieces:
thou sentest forth thy wrath, it devoured them as stubble.
8 And by the breath of thine anger the water parted asunder;
the waters were congealed as a wall,
the waves were congealed in the midst of the sea.
9 The enemy said, I will pursue, I will overtake,
I will divide the spoils; I will satisfy my soul,
I will destroy with my sword, my hand shall have dominion.
10 Thou sentest forth thy wind, the sea covered them;
they sank like lead in the mighty water.
11 Who is like to thee among the gods, O Lord?
who is like to thee? glorified in holiness,
marvellous in glories, doing wonders.
12 Thou stretchedst forth thy right hand,
the earth swallowed them up.
13 Thou hast guided in thy righteousness this thy people whom thou hast redeemed,
by thy strength thou hast called them into thy holy resting-place.
14 The nations heard and were angry,
pangs have seized on the dwellers among the Phylistines.
15 Then the princes of Edom, and the chiefs of the Moabites hasted;
trembling took hold upon them,
all the inhabitants of Chanaan melted away.
16 Let trembling and fear fall upon them;
by the greatness of thine arm, let them become as stone;
till thy people pass over, O Lord,
till this thy people pass over, O Lord,
till this thy people pass over, whom thou hast purchased.
17 Bring them in and plant them in the mountain of their inheritance,
in thy prepared habitation, which thou, O Lord, hast prepared;
the sanctuary, O Lord, which thine hands have made ready.
18 The Lord reigns for ever and ever and ever.”