A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines. Traditionally a "zig" points in the left direction (/) and a "zag" points right (\). (wiki)
This boat's name is a dialectal expression whose literal meaning is perfect for a sailing boat as it means "keep an eye out down below". The saying also means "careful what you say".
Update offered by Nereo:
"Ociodesoto" originally is a warning shouted by somebody working on scaffolds or on high structures/places to people passing/transiting below when a tool or another object or a lifted cargo for example, is falling or might fall.
Now is more used as an advice: Keep your eyes open because something wrong might happen to you."