[1] The headword is found in Homer, Iliad 3.47 (web address 1); see also the corresponding scholia and Eustathius ad loc.; similarly glossed in ps-Zonaras; cf. Hesychius and Etymologicum Gudianum s.v. ἐπιπλώσας and Etymologicum Magnum s.v. ἐπιπλὼς καὶ πόντον ἐπιπλώσας .
[2] Homer, Iliad 6.291 (web address 2).
[3] According to the scholia to the aforementioned Homeric quotations, πλώς is produced with apocope and not syncope (see LSJ s.vv. apocope II and syncope at web addresses 3 and 4).
[4] We would not call this participle "indeclinable"; but perhaps the point is that it has no suffix indicating its tense, although it does have a case-ending.