Hi, and welcome to the forum.
In Ship simulator you have a card, or kind of ECDIS(Electronic Chart Display and Information System). Which is for every environment of ship simulator. So for navigiation in an area you just look in the chart. The charts are not that detailed when they are a lot of out zoomed. So when that happenes you can not see all the names of the specific places in the chart
However Ship Simulator is build from different seperate environments. Only with mission when you reach waypoints you will switch from environments. So that can not happen with single- and multiplayer.
But getting to your question. Ship Simulator has not a route marker. So you can make routes in Ship Simulator so that you can sail them. It is more just sailing the environments, of course you go to specific places with the missions. But in your case sailling from Southampton to Cowes IOW, you need to know where they are in real, or sail with a real nautical chart. And than follow that to the destination. But that can not be progammed in Ship Simulator. So getting lost is pretty hard. Because you always have you chart.
Snaky