There are seven vehicular chain ferries in the UK, known amongst ferry fetishists as the Magnificent Seven*:

• Windermere Ferry, across Lake Windermere in Cumbria

• Reedham Ferry, across the River Yare in Norfolk

• Isle of Wight Floating Bridge, at the mouth of the River Medina on the Isle of Wight

• Sandbanks Ferry, across the mouth of Poole Harbour in Dorset

• Dartmouth Higher Ferry, across the River Dart in Devon

• Torpoint Ferry, across the River Tamar, connecting Devon and Cornwall

• King Harry Ferry, across the River Fal in Cornwall

The shortest route linking them is about 750 miles.  They all operate to their own timetables.  One of them is on an island.  We need to cross them all within 24 hours.

* for the avoidance of doubt, no one has actually ever called them this.

Maybe just, but we really don't know.  Here's the deal.

• We will start on the last crossing on the Windermere ferry in the Lake District, from Far Sawrey to Ferry Nab.  In June, that leaves at 22:00....

• ...our route ends the next day at the King Harry Ferry in Cornwall from Philleigh to Feock, where in June the last crossing is at 22:10.  We need to get the crossing before that to beat 24 hours.  Miss that crossing though, and the next one isn't until 07:10 the next morning, and we are scuppered.

But it's not just a case of a gentle potter between the ferries in between.  Don't believe the standard route planning apps, which don't account for ferry timetables.

• From Windermere we will drive through the night to the Reedham Ferry in Norfolk, the second ferry on our route.  That's about 300 miles, or six hours.  The first crossing here isn't until 06:30 though.  We're going nowhere till that ship sails....

• From Reedham, its just over 200 miles or about 4h30 to Portsmouth for the (non chain) ferry to the Isle of Wight.  It leaves at intervals of between 40 minutes and 1h20.  Hit a gap and we're sunk....

• Once on the Isle of Wight we have to get across the Cowes Floating Bridge and on to Yarmouth for the (also non chain) ferry to Lymington, back on the mainland.  That ferry leaves at intervals of one hour.  Narrowly missing one would torpedo the plan....

• From Lymington its on to the Sandbanks Ferry.  Looks lovely, but being in a beauty spot it gets busy in the summer.  If our planning assumptions are off, we're shipwrecked....

• From Sandbanks it's 200 miles to Dartmouth, Torpoint and on to beautiful West Cornwall.  The light is fading though and we're on rural B roads, a wrong turn and we're holed beneath the water line...

• Finally, King Harry by 22:00 and eternal glory.  King Harry after that, and all that awaits is fathomless ignominy.

• Oh, and we need hit up some EV chargers along the way to get enough juice in the battery.

Plug the Chain Ferry Challenge into the usual route planning apps, and the answer you'll get is deceiving, becasue they don't account for ferry timetables.  So, we've done our own modelling, charted below, based on the actual ferry timetables, and sensible ranges of assumptions for ferry loading/offloading time, driving segment times and EV battery performance and charging.  The science says that with a perfect run, we can do it, with a 30 - 40 minute buffer.  That though requires good traffic, no unexpected stops, breakdowns, waits or incidents along the way.  Taking the top end of estimated times for the driving segments (heavy traffic) and more conservative estimates for loading/offloading time, we arrive at King Harry about four hours after the last ferry.  Take a mid point and we miss the last King Harry ferry by about two hours.

Its very probable that the Chain Ferry Challenge is only possible (even theoretically) on a handful of days a year.

• In the winter, later first crossings and earlier last crossings on most of the chain ferries make the challenge impossible.  Even in Autumn, the service is reduced. The latest crossing at King Harry Ferry, 22:10, is only available June to August.  

• The Chain Ferry Challenge Challenge is impossible year round at weekends, due to later first crossing at Reedham.

• It turns out that chain ferries correlate with holiday spots (Cornwall, Devon, Dorset, IoW, Norfolk, Lake District).  During the school holidays in particular, traffic and ferry queues are liekly to make it extremely difficult, probably impossible.  For a sporting chance it needs to be in June before peak holiday season, also coinciding with longest daylight hours.  Going mid week to avoid holiday change over days is also good planning.

• Take account of all this, and you're down to a few days in June.  Factor in the Isle of Wight Festival in mid-June, and the window narrows further.  We think there are only a handul of days a year when it is currently possible.

It's difficult to believe that anyone who has read this far is pedantically minded, but its good to cover off all eventualities.  Here are some minor points:

• We are not differentiating between cable ferries (which use a lighter cable, usually on lakes or slower moving rivers) and chain ferries (which use a heavier chain, usually in tidal waters)

• There are a number of other excellent chain/cable ferries which are pedestrian only, including the Stratford-upon-Avon chain ferry and the Trowlock Island Ferry, which are not included in the Challenge.

• We mean chain ferry routes, and not individual chain ferries.  Torpoint ferry is a monster and has up to three ferries running in parallel - just one will do.