Canto 2 -
Ayodhyā-kāṇḍa
Chapter 55: Rāma Leaves Bharadvāja’s Āśrama and Crosses the Yamunā
Text 2.55.18

आरोप्य प्रथमं सीतां संघाटं परिगृह्य तौ।
ततः प्रतेरतुर्यत्तौ वीरौ दशरथात्मजौ॥

āropya prathamaṁ sītāṁ saṅghāṭaṁ parigṛhya tau
tataḥ prateratur yattau vīrau dāśarathātmajau

āropya = having [thus] boarded; prathamam = first; sītām = Sītā; saṅghāṭam = on to the raft; parigṛhya = held it; tau = it; tataḥ = and then; prateratuḥ = while swimming; yattau = endeavored to push; vīrau = the heroic; dāśaratha-ātmajau = sons of Daśaratha.

Having [thus] first boarded Sītā on to the raft, the heroic sons of Daśaratha held it and then endeavored to push it while   swimming.