Black and Green 1992 record that the gods had boats, and that these were actually
used when the gods (as cult statues) made ritual journeys to visit each other
in festival times. They say: "The god's boat would be stored in the temple and
it seems that the cult statue of the god and some of the god's or goddess's treasure
might be exhibited on the boat."

http://etcsl.orinst.ox.ac.uk/cgi-bin/etcsl.cgi?text=t.1.1.3#

Enki's boat is spoken of in the myth "Enki and Ninhursag", where this god's boat is
called the 'Stag of the Abzu', which according to R. Biggs may relate to some
pre-anthropomorphic conception of Enki as a stag, and Enki is still sometimes himself
referred to as 'stag of the abzu' (the concept being an analogy to
the reeds in the reed beds compaed to horns - this however is fairly loose.)
In the below extract, Nigir-sig is the captain of Enki's boat, and is apprently
a son of Enlil. Sirsir is a minor deity, a god of boats:

166-181. The lord, the great ruler of the Abzu, issues instructions on board the
'Stag of the Abzu' -- the great emblem erected in the Abzu, providing protection,
its shade extending over the whole land and refreshing the people, the pillar and
pole planted in the …… marsh, rising high over all the foreign lands. The noble
captain of the lands, the son of Enlil, holds in his hand the sacred punt-pole, a
meš tree ornamented in the Abzu which received the supreme powers in Eridug, the
holy place, the most esteemed place. The hero proudly lifts his head towards the Abzu.
6 lines missing or unclear

182-187. Sirsir ……, the boatman of the barge, …… the boat for the lord. Nigir-sig, the
captain of the barge, holds the holy sceptre for the lord. The fifty la?ama deities of the
subterranean waters speak affectionately to him. The stroke-callers, like heavenly gamgam
birds, …….