Thankfully your efforts are not in vain. The seemingly vast distance shrinks & the details of the old ship become clear; patterns of "dripping" rust seemingly forming stalagmites & stalagtites off of the top & sides of the dead vessel. The gaping maw Kain spotted, miraculously enough, opens over the waterline, seemingly gulping down seawater with a greedy thirst.

You row right in without any great difficulties, turning on the lights of your Pip-Boys to see the waterlogged interior. As you stop the slight momentum of your craft with oars pressed against the solid opposite wall, the torches of light reveal a stairwell slanted diagonally leading up to a bulkhead; treacherous, with your boots wet & the metal slick, but passable. Further into the gloom you spot a broken canoe propped upon a nearly submerged railing, but can't quite see if anything is inside. The interior of the ship is too narrow there to row over though, which means taking a swim might be necessary... On the other hand, perhaps simply waiting out the storm & taking stock of what is available between the four of you is the best course of action.
>Take the Slanted Stairs up to the Bulkhead
>Swim over to the Broken Canoe
>Take Stock of the Raft, your Companions, & the Vault you've emerged from
>Leave & Brave the Growing Storm
>Write-In

[I'll run a session when I get off work in about 3 hours]