This is Froghall Tunnel on the Caldon Canal in Staffordshire. It is a related-waterways place note — not Bolinder engine history. No named Bolinder boat is claimed in this bore. For hot-bulb sound and starts, stay on Sound & video. Bob Tidy filmed the squeeze here on Nb Battersea; that is a different boat from his Bolinder 1051 Andora.
| Kind | Very short, extremely low canal tunnel |
|---|---|
| CRT number | Tunnel 54 (Leek Tunnel is Tunnel 8 on the same sheet) |
| Waterway | Caldon Canal (Trent and Mersey branch) |
| Place | Ipstones / Froghall, Staffordshire Moorlands |
| Length | About 75–76 yards (about 68–70 m); published figures differ by a yard |
| CRT headroom | About 5 ft (1.52 m) after the 2003 pound-lowering |
| CRT cabin / beam | About 6 ft 8 in (2.03 m) through the tunnel |
| Live test | Hanging profile gauge at Flint Mill Lock 17 |
| Opened | About 1785 (530-yard extension after the 1783 Act) |
Why people lie on the cabin
This is not historic legging of the long tunnels (Blisworth, Standedge, Dudley, Braunston). Those bores had no towpath; crews lay on planks and walked the walls for miles.
At Froghall the problem is headroom. A modern cabin, grab-rail corners, chimney stub or cratch will hit the brick. Crews commonly drop chimney and aerial, try the plastic profile at Flint Mill Lock 17, and — if they go on — sometimes stop the engine and walk the boat the last yards. That is a modern squeeze, not a recreation of 18th-century legging.
This page records what crews actually do on film. It is not advice to lie on a moving cabin roof.
How low? Published figures disagree
Headroom has changed with water level. Older printed guides are tighter than post-2003 figures. Do not pick one number and pretend the others do not exist.
| Source | Headroom | Width note |
|---|---|---|
| Canal & River Trust (current boating note) | 1.52 m / 5 ft | 2.03 m / 6 ft 8 in beam through the tunnel |
| IWA Caldon notes | 5 ft 0 in (1.52 m) | Also lists other Caldon limits (locks, draught) |
| Older Nicholson / Geograph profile | 52 in (1.32 m) | Cabin width at top 66 in (1.68 m) |
| 1981 photo caption (pre-lowering) | 4 ft 4 in (1.34 m) | Water later dropped; still excludes many leisure boats |
Official modern wording is about 5 ft. Older profiles sat around 4 ft 4 in–52 in. The gauge at Flint Mill Lock is the only test that matters on the day. Local advice is that the hanging gauge can be a couple of inches pessimistic — still treat a kiss on the gauge as a warning, not a dare.
Other limits: the winding hole just before the tunnel is often given as about 65 ft; the last mile from Consall Forge is very narrow (two boats cannot always pass); hire firms often forbid the tunnel because roof corners get chewed. Unpowered-craft rules change — check CRT on the day.
Place in the Caldon
The Caldon runs about 17–18 miles from Etruria (Stoke-on-Trent) to Froghall, with 17 locks and two tunnels: Leek on the Leek Arm, Froghall on the main line. Leek Tunnel is longer and far more comfortable. Froghall is the one that makes people lie down.
Approach on the Froghall line:
- Hazelhurst Junction / locks / aqueduct (Leek Arm crosses overhead)
- Cheddleton locks and flint mill
- Shared river section Oakmeadowford to Consall Forge (River Churnet)
- Flint Mill Lock 17 — profile gauge
- Narrow pound, winding hole
- Froghall Tunnel
- Barnfield Aqueduct, Froghall Junction
- Froghall Wharf and the restored first lock of the Uttoxeter Canal (2005)
Why the tunnel exists
Trent and Mersey proprietors leased Caldon Low limestone. A locked canal to the quarry was impossible (about 700 ft of rise in four miles), so the 1776 Act authorised a branch canal plus a railway / plateway from Froghall to the quarry. The main line opened to the old Froghall wharf in December 1778.
The first horse tramroad was poorly engineered. A 1783 Act authorised a new tramway (about 3.1 miles) and a 530-yard canal extension including this tunnel, to a new basin better placed for interchange. Extension and tunnel opened about 1785.
The tunnel exists because the interchange moved to the other side of the hill. It is an early canal tunnel built to marry canal and railway, not to punch a long summit.
Later, Froghall was a limestone / limekiln / copper-works interchange. The Uttoxeter Canal left Froghall Junction (opened 1811, closed 1849); much of its bed was taken by the Churnet Valley railway.
The Froghall line slid toward dereliction in the early 1960s, reopened in 1974, and gained cruising-waterway status in 1983. 2003 “Destination Froghall” repaired the last pound and lowered the water so more boats could pass without losing depth — headroom improved to about 5 ft. Even then, many modern leisure boats still will not fit. In July 2005 the first Uttoxeter lock and a second basin were restored.
Films
These public films are for education and atmosphere. They are not owned by this site. Credit the uploaders, and use the official YouTube player only. No autoplay. They show the place. They are not Bolinder engine films.
Have you filmed a Bolinder in this bore?
Public search (September 2026) finds strong Froghall films, not a clip that is clearly a Bolinder working this tunnel with audible hot-bulb exhaust. Echo in a low brick hole would be gold. If you have one, please contact us for credit and embedding.
Nearby
- Consall Forge and the Black Lion
- Cheddleton Flint Mill
- Churnet Valley Railway, Froghall station
- Hazelhurst Aqueduct and the Leek Arm / Leek Tunnel
- Cauldon Low quarry landscape above the valley
- Restored Uttoxeter Canal lock and basin (2005)
Walk to Froghall Wharf even if the boat cannot: limekiln remains, the railway station, and the restored lock. This is not a shop and not a travel-ticket page.
Not a navigation guide
Dimensions, stoppages, and unpowered-craft rules change. For a visit or a passage, use Canal & River Trust — Boating the Caldon Canal and the current notices. Ticket prices and tea-shop hours are not listed here.
FAQ
Is this a Bolinder engine page?
No. This site is about Bolinder marine diesels. Froghall Tunnel is a related-waterways place note — a very low canal tunnel, not an engine. Bolinder sound and starts: Sound & video.
Why was someone on their back in the tunnel?
Headroom. It is not historic long-tunnel legging. A cabin, chimney stub, or grab-rail corner hits the brick, so some crews walk the boat through with the engine off. That is a record of practice, not a recommendation to stand on the roof underway.
How low is Froghall Tunnel?
Canal & River Trust currently gives about 5 ft (1.52 m) headroom and 6 ft 8 in (2.03 m) beam through the tunnel, after the 2003 pound-lowering. Older printed profiles were tighter (around 4 ft 4 in to 52 in). Use the hanging gauge at Flint Mill Lock 17 on the day.
Why does such a short tunnel exist?
Limestone. The 1783 Act extended the canal about 530 yards, including this tunnel, so a new basin could sit beyond the hill with a better tramroad to Caldon Low. The extension opened about 1785.
Is Nb Battersea the same as Andora?
No. Bob Tidy filmed Battersea (National 2DM) at Froghall in 2017. Andora is his Josher-style boat with a Bolinder 1051. Same skipper, different boat.
Can every boat reach Froghall Wharf by water?
No. Many modern leisure cabins still will not fit, even after 2003. Boats that fail the gauge can wind before the tunnel; the last mile is very narrow. The wharf, kilns, and railway are worth the towpath walk either way.
Facts drawn from Canal & River Trust Caldon boating, Froghall (further reading), National Transport Trust / Railway & Canal Historical Society notes on the 1783 extension, CanalPlanAC, and the films above. Films are not owned by this site.
Related: Locations hub · Falkirk Wheel (another related-waterways note) · Bath Locks · Andora · Sound & video