What must you do if you see another vessels read and white lights off your starboard bow?

If you see another vessel's red and white lights off your starboard bow, it indicates that the other vessel is crossing from your right side. You should maintain your course and speed, as the other vessel is likely the stand-on vessel. However, be prepared to take action if necessary, ensuring you can safely avoid a collision. It's also important to monitor their movement and assess the situation continuously.