catascopus
From LSJ
βορβόρῳ δ' ὕδωρ λαμπρὸν μιαίνων οὔποθ' εὑρήσεις ποτόν → once limpid waters are stained with mud, you'll never find a drink
Latin > English (Lewis & Short)
cătascŏpus: i, m., = κατάσκοπος (exploring, spying (cătascŏpĭum, ii, n., Gell. 10, 25 fin.), = κατασκόπιον,
I a lookoutship, a spy-ship, a vessel sent out to reconnoitre (pure Lat. navigium speculatorium), Auct. B. Afr. 26; cf. Isid. Orig. 19, 1, 18.
Latin > English
catascopus catascopi N M :: light vessel for reconnoitering