The tunnel is also really cold, so pack a jumper or a coat. It's between 4 and 6 degrees, so a bit like sitting in a fridge for two hours. It's dark, there's a good long while where you can't see the light at either end, but the boat has lots of light on it. The canal is narrow, barely wider than the boat at times. My mum was worried she'd be claustrophobic but there's plenty of wider parts and also lots of space above the boat, which made me feel better. Just be aware if you're very claustrophobic.
Here's some photos, my stepdad took them all I think.
This is Tunnel End at Marsden. The leggers used to live in the cottages on the right. Above this is a lot of moor, this is really low down!
This is the sister to the boat we went on but they're identical, about seven feet wide I think
My mum and me standing by the tunnel end. The canal is around 2m deep which is really deep for a canal (most of the time, if you fell in one you'd be easily able to stand up in it)
This is the entrance at Diggle. The gates have leggers on them
The view from the front of the boat and the driver, who had to keep adjusting the steering. Here the canal is brick lined, which it is in places due to the train tunnel nearby. You can hear the trains and feel the draughts from them too!
But in the middle, where the train lines don't go, the canal is hewn out of the rock
Here, you can see the marks from where the navvies used a hand drill to get through the hard gritstone.
Is that light at the end of the tunnel...?
Yes, yes I think it might be!
And here's a really gorgeous photo of the sister ship framed in the tunnel entrance.