Read the following sentence.

Rusty and Walt were old hands, but even they were feeling squeamish. The pair had been sailing the high seas of French Polynesia aboard Captain Jack's ship, The Rapscallion, for almost a year now.

What is the meaning of the bolded phrase?

Rusty and Walt are feeling nauseous.
Rusty and Walt are mean, old men.
Rusty and Walt are ready to quit their job.
Rusty and Walt have experience on ships.