Ferries are the civilised way to travel. You drive on, walk upstairs and let somebody else do the driving for a couple of hours. The part that catches people out is the ten minutes after the announcement asking passengers to return to their vehicles. Whatever you left in the boot stays in the boot, and whatever is in your hand luggage is all you have.

Pack for the crossing, and for that moment you have to leave the car, and the whole day runs more smoothly. Here is a checklist worth working through before you set off.

Start with the things you cannot replace

Everything else on this list can be bought at a service station or borrowed from a fellow passenger. Passports and medication cannot. Keep them on your person — a zipped pocket or a small crossbody bag that never leaves you — rather than in the depths of a rucksack.

• Passports or ID cards for every traveller, checked for expiry. Some countries require a set period of validity remaining on your passport, so check the entry rules for your destination and nationality before you book.
• The booking reference, saved offline on your phone and written on a scrap of paper as a backup.
• Travel insurance details and an emergency contact number.
• Prescription medication in its original packaging, with a copy of the prescription. If you are crossing borders with controlled medicines, check the requirements well in advance — some countries ask for a letter or permit.
• A payment card and a small amount of cash in the local currency for the other side.
• Written directions to your first stop. Do not rely on a phone that may die or a satnav that is sitting in the car.

Hand luggage that earns its place on deck

Ferry decks are windy whatever the forecast promised, and the lounges can be cold, crowded or both. A layer you can pull on without opening a suitcase is worth more than anything else in the bag.

• A refillable water bottle, filled before you board where you can.
• Snacks that travel well — nuts, fruit, oatcakes — especially with children in tow.
• A warm, windproof layer and, for open decks, a hat.
• A charged power bank and cable. The charger in the car will not help you at a table upstairs.
• Headphones and a book, or something downloaded for a longer crossing.
• Tissues, wet wipes and hand sanitiser.
• Nappies, wipes and a full change of clothes for babies and toddlers.
• A foldable tote for anything you buy on board, and a small bag for rubbish so you are not juggling wrappers.

A note on bag searches

Ferries do not usually apply airport-style liquid limits, but operators can and do search bags, and coach passengers sometimes face different rules again. Keep anything you would rather not have unpacked — medication, for instance — near the top of the bag rather than buried at the bottom.

The car deck rush: what people forget most

This is where a checklist earns its keep. You have parked in a tight row, taken what you can carry and joined the queue at the stairs. Halfway up, the questions start: where are the keys, who has the dog's lead, did anyone bring a jumper?

• The car keys. Decide now who carries them, and keep them in the same pocket for the whole crossing.
• Your deck and lane number. A note or a photo of the car on your phone saves a long hunt on a big ship.
• The dog's lead, collar, bowl and a bottle of water. On most routes pets stay in the vehicle, so leave a familiar blanket, a shade screen for sunny days and a bowl that will not tip.
• Baby changing kit, taken upstairs with you rather than left in the boot.
• A layer for everyone, even in August. The deck is exposed and the wind does not care about your plans.
• Something to do that needs no screen, for when the signal drops or the battery runs out.
• Onward directions, if your route relies on a satnav that is still in the car.

Pet policies differ by operator and by route, and not every ship has pet-friendly cabins, so read your operator's rules before you travel rather than assuming.

Children, pets and passengers who need a little more

Children find the first twenty minutes of a crossing thrilling and the next hour very long. A small bag of their own, packed by them, solves most of it: a favourite toy, a card game, snacks they chose, a spare pair of socks. If you are travelling overnight, put pyjamas and toothbrushes in the hand luggage so nobody is digging through the boot at midnight.

If someone in your group gets seasick, plan ahead rather than hoping for the best. A pharmacist can advise on suitable remedies before you travel. On board, it usually helps to sit low and towards the middle of the ship, get some fresh air and keep something bland in your stomach. Seek advice from a pharmacist or doctor if you are unsure, particularly if you are pregnant or taking other medication.

Food, drink and the weather you did not plan for

Onboard cafés are perfectly good, but they get busy the moment the ship sails. Travelling with young children or on a tight schedule? Eat before you board or bring your own. A flask, a couple of mugs and a bag of tea bags will see you through a winter crossing for very little.

Weather changes quickly at sea. A calm morning can turn into a breezy afternoon, and the open deck is always cooler than the terminal car park. Layer up, wear shoes you could walk in on a moving floor, and keep a light waterproof where you can reach it.

In the boot, but worth being able to reach

A handful of items should be gettable without unpacking the whole car, and some of them are legal requirements in certain countries.

• Hi-vis vests and a warning triangle, where your route requires them.
• Jump leads, a tyre inflator and a torch.
• Screen wash and a cloth for the windscreen.
• Vehicle paperwork: insurance, MOT details, and a letter of authority if you are driving someone else's car.

Requirements vary from country to country, so check the current rules for every country you will drive through — including the one you are leaving — before you set off.

A five-minute routine before you board

1. Put passports, tickets, keys and medication in one bag, and give it to one person to carry.
2. Fill water bottles and use the toilets while you still can.
3. Check everyone has a layer, and that pets have water.
4. Note your deck and lane number.
5. Take the hand luggage out of the boot before you join the queue, not after.
6. Agree a meeting point on board in case you split up.

Then relax. The car is settled, you are on board, and everything else can wait until the other side.

Photo: Alexas_Fotos / Pixabay