Three naval craft were ordered to set sail for drills with the US and Italian navies off the Italian coast on Saturday night, only to be informed at dawn that their commander pranked them for April Fool’s Day.

The ships’ officers labored all Saturday night to chart a course for the 10-day cruise, and the crew readied their gear and had their parents bring whatever they lacked. The ships were rigged and fueled and ready to sail, and the crew stood at attention on deck.

Only then did Maj. Gen. Ram Rothberg inform them there was no drill and that the whole affair was a joke.

Some of the sailors and their parents were not amused, Israel Radio reported.

The IDF spokesman’s office characterized the prank as “inappropriate” and said the incident would be investigated and lessons would be learned.

The navy is currently conducting a real drill jointly with Greece and the US, however.