The official Gargantia site has posted a new preview video of the OVA, set to be released with the first Blu-ray box set on August 28, along with a look at Yuichi Nakamura (Oreimo's Kyōsuke Kōsaka) voiced Ritenour.
The OVA also features Yui Horie (Chie in Persona 4, Raika Oda in Listen to Me, Girls, I'm Your Father!) as Storia
And there's more tribute art..
by Tetsuya Kobayahsi
by Riri Sagara