Disturbed suitors

Obviously, the suitors are disturbed and depressed, not only has their plan failed, they also failed to plan for failure, there's no plan B. Telemachos, son of Odysseus, has unexpectedly outsmarted them by expecting their ambush and sailing past the pointy islands to avoid it. They are also worried because they're halved in numbers, a large group of the suitors is still lying in ambush at the tiny island of Asteris, a mission they had to undertake themselves.

They came outsite the hall past the large wall of the court and they set down in front of the gates.

Ithaca

Odyssey Book 16 line 325 Barry B Powell
Odyssey Book 16 line 326-327 Barry B Powell
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Odyssey Book 16 line 334-336 Barry B Powell

They want the rest back as quickly as possible, but there's another problem, the wind appears to be against them:

He had not finished speaking when Amphinomos, turning from his place, saw the very ship within the deep harbor. The men were furling the sails, or they had oars in their hands.

"But come, let us launch a black ship, the best we have, and let us gather seamen as oarsmen who as soon as possible can announce to our fellows that they should come home immediatly."

But the suitors were disturbed and depressed in their spirits.

Homer describes how they sneak out of the palace and go outside the gates, presumably to talk in secret. They know they're in trouble, one of the suitors says:

Eagilips

Ithaca harbor

Asteris

Samos

The female slaves near Penelope who overheard herald Medon's message to Penelope, soon spread the news to the suitors: Telemachos has returned from Pylos unscathed!

The returning ambush ship used its sail, so the wind has to be south. Also, the suitors on board would've been the best oarsmen and seamen to ensure the best chance for the ambush to succeed and like Eumaios said, they are with many, but now both the remaining suitors and Eumaios have seen the ship return to Ithaca.