Educational rewrite drawing on material preserved from the historic bolinder-engines.info archive (including a mid-1950s Bolinder-Munktell presentation and hot-bulb chronology associated with notes passed through Janette Horton and John Pattle).
- Swedish roots
- Hot-bulb development
- Types on the canals
- Character of the engines
- British waterways
- Later four-stroke 105x
Swedish roots
In 1844 brothers Jean and Carl Gerhard Bolinder established a workshop and foundry in Stockholm (some records say 1845). Early production included steam engines and woodworking machines; by the 1890s oil engines were part of the programme, and Bolinder motors gained an international reputation.
Separately, Johan Theofron Munktell founded workshops in Eskilstuna in 1832 — lathes, steam engines, and in 1843 the first Swedish steam locomotive — before agricultural machinery became central. In 1932 Bolinder and Munktell amalgamated as Bolinder-Munktell, with head office and main workshops in Eskilstuna. A mid-1950s company presentation noted that roughly every fifth person in the town earned a living, directly or indirectly, from the firm — a reminder of how large the industrial footprint had become by the tractor and diesel era.
Hot-bulb and semi-diesel development
From 1893 Bolinder was already building four-stroke paraffin engines of up to about 30 hp. In 1902 F. A. Rundlöf invented a two-stroke crank-chamber scavenged hot-bulb engine and passed the design to Bolinder. That line — sometimes described as a two-stroke Hornsby–Akroyd type — became the classic Bolinder semi-diesel family so often associated with European workboats and UK canals.
Direct reversing was patented in 1906. Early engines used hit-and-miss governing; marine practice often required de-clutching from the propeller to reverse — not “positive” in the modern sense, but well suited to barge work where manoeuvres are deliberate rather than racing.
Type chronology (E → M → NE → BM)
The archive preserves a clear development ladder. The summary below is rewritten for modern readers; ratings and practices vary by installation and should not be treated as workshop limits.
| Year | Type | Notes |
|---|---|---|
| 1908 | E | 1, 2 or 4 cylinders up to ~320 hp; fixed-arc sprayer; large uncooled bulb area; water injection via transfer passage under load (boatmen often ran with the drip off, accepting higher cylinder wear); hand fuel-pump stroke for “no miss” cruise. |
| 1914 | M | Up to ~500 hp; water injection replaced by compressed-air blast (engine-driven compressor) that both injects and cools; mainly higher powers, with E continuing for lower powers. |
| 1921 | NE | Supersedes previous; roughly 6–500 hp; variable-arc spray; bulbs stay black under full load; 10–30% power gain; air damper / heater box on most sizes; earlier injection; optional electric flow-plug start (~30 s). |
| 1924 | WM | Lightweight 6 / 12 / 24 hp at 900 rpm; governor-linked injection; gearboxes; saltpetre touch-paper start. |
| 1925 | BM | “Deep head” vs NE “shallow head”; better scavenging and compression; larger crankshaft / counterweights / clutch; lighter rod, hollow gudgeon. The type most often surviving on UK canals. E/M could be converted to BM for more bhp, lower fuel use, ability to idle without the lamp, no water drip, better flexibility. |
| 1926–30 | Refinements | Quick-start lamp (~2 min on fuel oil, 1926); gearboxes to ~120 hp (1928); improved enclosed lubrication box (1929); cold-start 400 hp at 275 rpm (1930). |
Canal practice often quoted engines as “15 hp” or “9 hp” when the iron was a derated larger frame (for example 20s derated as 15s, 12s as 9s). Some tug installations ran closer to full rating.
Character of the semi-diesels
- Hot-bulb ignition: a lamp (or later flow plug / quick-start device) heats the bulb; once running, residual heat sustains ignition.
- Direct reversing on many marine types, with de-clutch to reverse — well matched to barge handling.
- Slow speed and robustness: long-duty workboats rather than high-revving road engines; distinctive exhaust beat still recognised by enthusiasts. Hear it on Sound & video.
- Fuel: period notes give specific consumption around 0.55 lb/bhp/hr for larger units (say ~0.6 for smaller canal motors before gearbox losses) — useful orientation only, not a modern dyno claim.
On British waterways
Bolinder semi-diesels became familiar on UK canals and rivers because they suited slow-speed, hard-working inland craft: narrowboats, barges, tugs and working boats that needed reliable propulsion rather than high-revving performance. That is why period manuals, owner lore, and survivors at rallies still matter to the waterways community.
On this site, boat stories that touch the earlier line include President (FMC steamer converted to Bolinder crude-oil power in the inter-war years) and Minnow (historic motor later fitted with a Bolinder BM9). Later four-stroke craft such as Andora (1051) sit on a different technical branch — see below.
Later four-stroke 105x marine diesels
The single- and multi-cylinder four-stroke Bolinders often met on modern UK canals as 1051 / 1052 / 1053 / 1054 are a later family than the hot-bulb BM line. They share the Bolinder name and waterways culture, but manuals, parts and workshop practice differ. Treat them separately: use Models for family overviews and Manuals and Registers for the published four-stroke PDFs.
Workshop projects on this site — Labour of Love and 1051 No. 1001 — document a four-stroke spares strip linked to Andora, not a semi-diesel rebuild.
What this site is (and is not)
- Is: an educational heritage reference for Bolinder marine engines and their UK waterways context.
- Is not: a shop, a complete technical manual, or a copy of every old archive page.
- Technical work: always prefer original manuals and qualified engineers; pages here are orientation, not certification.
Type chronology and practice notes rewritten from archive semi-diesel history material. Boat and project links lead to modern pages already on this site.