Ferries turn a coastal route into something more interesting and introduce a dependency that ordinary road planning does not have. I have been caught out twice and now plan around them quite differently.
They are weather dependent and the threshold is lower than you think
The central fact. A ferry can be cancelled in conditions that look entirely manageable from shore.
The limiting factor is frequently not the crossing itself but the ability to berth safely at either end, which depends on wind direction relative to the harbour entrance. A wind that is fine for the passage can make docking impossible.
Small vessels on exposed routes cancel considerably more often than large ones on sheltered ones, and open-deck vehicle ferries are more sensitive than enclosed ones.
Which means the cancellation risk is a property of the specific route, and local knowledge about how often that route runs in a given season is worth seeking out.
What cancellation actually means for a route
The reason it matters more than a delayed road.
A closed road usually has an alternative. A cancelled ferry frequently has none, or has an alternative involving several hundred kilometres of driving around an inlet.
The next sailing may be in six hours, tomorrow, or in three days on a route running twice a week.
And if the cancellation is weather driven, the backlog means the next sailing is full of everybody who was booked on the cancelled one, which puts you further down a queue.
This is why a ferry in the middle of a route is a manageable risk and a ferry as the last leg before a flight is not.
Booking, and whether to
Depends heavily on the route.
Vehicle space on popular routes in season sells out well ahead, and turning up hoping is a poor strategy. Foot passenger space almost never does.
On busy routes, booking is essential. On quiet local routes it is frequently unnecessary and sometimes impossible.
Worth checking whether a booking guarantees space or merely reserves it subject to conditions, and what happens to it if a sailing is cancelled — some operators roll it forward automatically, some require you to rebook, some refund.
Also worth checking whether the return is separately booked, because a one-way is frequently much more than half a return.
The practical timing
Ferries want vehicles at the terminal substantially before departure, often thirty to sixty minutes, and late arrival forfeits the booking.
Loading and unloading takes longer than people plan for, particularly on busy sailings.
And the crossing time quoted is dock to dock, so a forty minute crossing is closer to two hours of your day once queuing, loading and unloading are included.
Building that into a route rather than treating the crossing time as the cost is the difference between an easy day and a rushed one.
What to do with the time
The upside, and it is real.
A ferry is the only part of a driving day where the driver is not driving. Meals eaten on ferries are frequently the most relaxed of a road trip for exactly this reason.
The view is generally the best of the route, and the perspective on a coastline from the water is different from anything the road gives you.
And on longer crossings there is genuine rest available, which for a driver on a multi-day route is worth more than the time cost.
My planning approach now is to treat a ferry as the day's main event rather than as transit, which changes the whole shape of the schedule.
The rules that have kept me out of trouble
Never put a ferry between yourself and a flight, unless there is a full day of slack.
Check the sailing schedule for the actual date rather than assuming, because schedules change seasonally and some routes do not run every day.
Have a plan for what happens if it is cancelled, even a rough one, before setting off.
Arrive early rather than exactly on time, since the queue is the variable.
And check the operator's cancellation notifications on the morning, which most publish and which is the difference between finding out at home and finding out in a queue.
Foot passenger as a fallback
A tactic worth keeping in mind on routes where vehicle space is the constraint.
Foot passenger capacity almost never sells out, and on many routes it is a fraction of the vehicle fare.
Which means that leaving a hire car on one side and hiring another on the other is sometimes both cheaper and more reliable than taking a vehicle across, particularly for a short stay.
It also removes the risk of being unable to get the vehicle back on a booked sailing, which is the situation that turns a cancellation into a genuine problem.