The noun is diminutive. Rev., the little boat. It is hardly probable that this refers to a smaller boat accompanying the vessel. Compare the alternation of πλοῖον and πλοιάριον in Joh 6:17, Joh 6:19, Joh 6:21, Joh 6:22, Joh 6:24.
Two hundred cubits
A little over a hundred yards.
With fishes (τῶν ἰχθύων)
Or, the net of the fishes. So Wyc, Rev., full of fishes.