Emily Hartley
The Grand Union in brief: what you're taking on
The Grand Union is the spine of the English canal network. The main line runs roughly 137 miles from Brentford, on the Thames, up through the Chilterns and the Midlands to Birmingham, with 166 locks along the way, plus the Leicester section and a handful of arms that are well worth a detour. It is a historic, working canal rather than a pretty rural backwater, and that is exactly what makes it rewarding.
The character changes as you go. South of Napton the locks are wide, built to take two narrowboats side by side, which means you can share the work with another crew and halve the time it takes to get through a flight. North of Napton the locks narrow and the canal becomes more intimate, with the long, cold darkness of the 1.8-mile Blisworth Tunnel and the famous Hatton flight of 21 locks waiting for anyone heading towards Warwick.
If you are planning a summer cruise, decide early whether you want a gentle out-and-back or a proper end-to-end passage. A week comfortably covers 40 to 60 miles with time to stop, eat and explore. Trying to do 100 miles in seven days is possible, but it turns a holiday into a shift pattern.
Getting the boat ready before you cast off
Most summer breakdowns are caused by something that could have been spotted in April. Work through the engine bay before the season starts: oil and filter, coolant level, alternator belt tension, fuel filters and the stern gland, which wants greasing little and often rather than once and generously. Check the weed hatch seal, test the bilge pump by hand and make sure the batteries hold charge under load.
Out of the water, a narrowboat wants blacking every two to four years, and anodes checking at the same time. Budget somewhere between £800 and £1,500 for a 57-foot boat to be docked and blacked, depending on where you are and how much preparation you do yourself. Chances are your boat safety certificate, insurance and waterways licence all fall due at inconvenient moments, so diarise them in spring rather than discovering the problem at the first lock.
Finally, service the domestic side. Gas bottles full, water tank flushed and sterilised, fire extinguishers in date, and a spare windlass, mooring line and set of keys stowed where you can reach them without emptying a cupboard.
What a week on the water actually costs
Running costs are modest compared with most holidays, but they add up quietly. A typical diesel engine burns somewhere between a litre and a half and two litres an hour, so a week of steady cruising with plenty of lock idling might use £100 to £150 of fuel at current red diesel prices for propulsion. Charging batteries and running a generator is charged at the domestic rate, so ask the supplier to split it properly.
- Pump-out: around £20 to £25, roughly every two to three weeks for a couple
- Gas: a 13kg bottle lasts most crews a month in summer
- Casual overnight moorings at a marina: £10 to £25 a night
- Towpath moorings: free for up to 14 days where no signs say otherwise
- Year-round licence: four figures for a typical narrowboat, and best paid by monthly direct debit
Keep a float of cash or a card for the small stuff — honesty boxes at water points, a pint at the end of a flight, and the coal or fuel boat that appears when you least expect it.
Locks, tunnels and pacing your days
Allow ten to fifteen minutes per lock with an efficient crew, and up to twenty if the paddle gear is stiff or a boat is coming the other way. A flight of ten will take 90 minutes to two hours; Hatton's 21 locks are a solid half-day's work and a wonderful half-day's work at that, with the café at the bottom worth a stop before you start.
Plan three to four hours of cruising a day, which is roughly 12 to 18 lock-miles depending on the water. Share locks and tunnels wherever you can: it saves water, saves time and turns a solitary passage into a conversation. In Blisworth Tunnel, switch on your tunnel light, keep to the centre of the channel and resist the urge to steer around the drips.
Watch the calendar too. Hire boat changeover days, usually Fridays and Saturdays, are the busiest times on the popular stretches, so move on those days if you can and linger midweek.
Moorings, water and everyday life afloat
Popular visitor moorings at Braunston, Stoke Bruerne, Napton and Berkhamsted fill by early afternoon in July and August, and most are restricted to 48 hours. If you want a marina berth for a night or two, ring ahead — many take bookings, and arriving unannounced on a Saturday evening is a gamble. Have a plan B stretch of towpath in mind, and remember that mooring on a bend, at a winding hole or opposite a water point will make you no friends.
Water points appear every few miles, usually paired with rubbish disposal, and elsan emptying points are marked on any good map. Fill up whenever you pass one, even if the tank feels half full. Genuine waterway life is in the small rituals: the kettle on while a lock fills, a walk to the village shop for bread, and a pint in a canalside garden while the light goes gold.
Keep the schedule flexible
The best-laid cruising plan meets a broken paddle, a hire boat learning the ropes, or three days of rain. Build slack into your itinerary, choose a turnaround point you are happy to abandon and never let the timetable push you into cruising tired at dusk. A summer on the Grand Union rewards patience and curiosity. Slow down, let the lock queue form without resentment, and you will arrive home with a suntan, a few new friends and a boat that still works.
