Start with the hull and the watertight bits

Before you think about fuel or fenders, take twenty minutes to walk the outside of the boat with a torch and a dry cloth. On a narrowboat or cruiser, small problems become expensive ones once you are three locks from anywhere. Check the bow and stern welds for rust streaks, and look closely at the rubbing strake, which takes the brunt of contact with lock walls. If you can see bare metal or bubbling paint, note it and mention it to the hire base or your marina.

Open the weed hatch, if your boat has one, and clear any debris from the propeller. Even a length of fishing line or a plastic bag wrapped around the shaft can cause vibration and overheating. Refit the hatch and make sure the seal is clean and the clamp is tight. A weed hatch that is not properly seated will let water in under way, and that is a miserable way to start a holiday.

Bilges come next. Lift the cabin floorboards and look for standing water. A small amount is normal, but if it is more than a centimetre or two, investigate before you leave. Check the stern gland, the packing around the propeller shaft, and give it a quarter turn on the greaser if it has one. It should drip slowly when the shaft turns, not pour.

Fuel, water and the systems that keep you comfortable

Diesel boats should be topped up before departure, but do not fill to the very brim in summer, because fuel expands in the heat. Know roughly how much you burn: a typical narrowboat uses about 1.5 to 2 litres an hour at cruising speed, so a week's gentle pottering might use 40 to 60 litres. Keep a note of how much you started with so you can spot a leak.

Water is the one thing people underestimate. Most canal boats carry between 300 and 600 litres in the fresh water tank. A family of four using showers, washing up and a loo will get through that in three or four days, so plan to fill at every water point you pass. Take a hose with a suitable fitting, and fill the tank until it overflows so you know it is genuinely full.

Check the following before you cast off:

• Fuel filter and water trap: drain any water from the bottom of the trap into a jar. Water in diesel is the most common cause of a boat spluttering to a halt mid-canal.
• Batteries: check the terminals are clean and tight, and that the electrolyte level is above the plates on lead-acid types. A rested battery should read around 12.6 to 12.7 volts.
• Charging: run the engine for ten minutes and confirm the voltmeter rises to 13.5 to 14.4 volts. No rise means no charging, and no charging means no lights, pump or fridge after a day.
• Gas: know where the bottle is, how to change it, and that the isolator works. Test the bubble tester or use soapy water on the joints, never a flame.
• Toilet: if you have a pump-out, confirm the tank is empty before you set off. Cassette users should carry a spare cassette.

Safety gear that must actually work

Life jackets are not optional, especially for children and non-swimmers. Inflatable jackets should be checked for a punctured bladder, a charged cylinder and an in-date firing mechanism. A jacket that has been sat in a damp locker for two years may well not inflate. Pull the toggle on an old one, or ask the hire company to demonstrate the ones they supply.

Check that you have a fire extinguisher within reach of the galley and one near the cabin exit, plus a fire blanket by the hob. Test the smoke and carbon monoxide alarms with the button, and replace batteries if there is any doubt. Carbon monoxide is a genuine risk on boats with solid fuel stoves and gas appliances, so never block ventilation grilles, even on a cold evening.

You will also want a boat pole, a boat hook, a mooring hammer or pins, and at least four good fenders. A windlass for every person on board, plus a spare, is worth the small cost. Keep a torch, a basic first aid kit and a charged mobile phone in a waterproof pouch. Add a copy of the canal map or guidebook for the waterway you are cruising.

Plan the route before you leave the mooring

Pick a route that suits your crew, not your ambition. A relaxed pace on a narrow canal is around three miles and two to three locks an hour. A flight such as Hatton or Caen Hill can take half a day on its own, so factor that in honestly. If you have never worked a lock, allow extra time and watch a couple of boats first.

Check stoppages before you go. Navigation authorities publish notices about lock closures, dredging and bridge repairs, and a scheduled closure can ruin a carefully arranged week. Note where the water points, sanitary stations, pubs and winding holes are, and identify two or three places you would be happy to stop overnight. Do not plan to cruise after dark, and remember that you cannot moor on some stretches overnight.

Finally, tell someone ashore your rough plan and expected arrival points. Give the boat's name and index number. It is a small courtesy that turns a worrying afternoon into a simple phone call, and it means you can relax and enjoy the slow, green, unhurried pleasure of the cut.