Luffy floundered to the choppy surface of the river, momentarily grateful as he realized it was fresh water and he wouldn't sink automaticaly. Drowning, however was still very possible in the turbulent waters. He wrapped himself around Nami to protect her from rocks and keep her with him as they were swept along. The captain was relying heavily on his own natural ability to float but the current was too strong and the two found themselves pulled under time and time again.
They floundered and fought, clinging to one another to keep from losing each other as well as avoid getting smashed against the rocks that jutted from the white water. Both were successful for a time until Luffy cried out as they were slammed against one of the sharp rocks, the current pinning them there. Pain ripped its way up the rubber mans back even as he struggled to free them, Nami forced against him