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Explanation & Abbreviations


Steam Canal Tug

Although not a genuine original, this boat is probably the closest working example of a steam canal tunnel tug on the waterways today. This is particularly so as both the hull and engine date from the end of the 19 th century.

The hull is built from the stern ends of two horse-drawn Birmingham ‘Joey’ boats built of iron in the late 1880’s or 1890’s with recent counter and cabin top. Conceived and built as a steamer by Chris Stubbings in the 1980’s, Adamant has never been powered by anything other than steam.

The machinery is well forward so that the funnel in the correct steam tug position; the original boats were little more than a floating steam engine with the machinery occupying nearly half the boat’s length. This meant they had the necessary ‘grunt’ to tow a string of maybe 12 boats at a time.

Adamant has a compound engine built by Cochrane of Birkenhead probably in the 1890’s (in any event before 1902 when the company moved to Annan in Scotland). Its early history is unknown but it is likely to have been used as the engine for a yard launch. The cylinder sizes are 4” dia for the High Pressure and 8” for the Low Pressure, both having a stroke of 5”. At 200rpm the engine produces about 5-7 HP and swings a propeller 24” in diameter with a pitch of 33.5”.

The compound engine is more efficient than a similar size ‘Single’ as the steam is expanded twice on its way to the exhaust. Efficiency is further increased by condensing the exhaust steam back to water and thereby producing a partial vacuum on the exhaust side of the engine. The resulting condensate is then returned to the boiler by the feed pump so that the level in the boiler remains constant.

The engine runs a number of pumps: the Feed pump noted above, a Circulating pump to pass cold canal water through the condenser to cool the exhaust steam, an ‘Air’ pump to extract the condensate from the condenser thus forming the vacuum and a 5-way oil pump for engine lubrication. These all live in the wooden box at the back of the engine and are chain driven.

The engine has ‘Stevenson’s Link’ reversing gear which changes the valve events to reverse the direction of rotation, hence no gearbox is needed. It is operated by the vertical lever at the front of the engine.

Steam is supplied from the boiler, which was built in 1986. The type is a Vertical Fire Tube and it is 3’ in diameter by 3’ high with 170 1” diameter tubes carrying the hot gasses from the fire up through the water, there is also a ‘water wall’ surrounding the coal fire which burns at the bottom on a 2 ft diameter grate. There is normally enough natural draft to produce the steam required although extra draft can be produced by means of a steam blower. The water level (most important!) is shown by the vertical glass tube behind a heavy glass protector. Additional water feed can be supplied from the canal by means of steam injectors. The boiler pressure is shown by the big gauge above the boiler and normal operating pressure is round about 100 psi. The maximum pressure is 125 psi. Coal consumption is quite low – about 3 bags per day including lighting up – say 75-80 kgs. The group of three pressure gauges above and behind the engine measure the pressures of the steam at various stages as it passes through the engine.

A minimum crew of two is required, a steerer and an engineer.

Adamant’s home base is at Stockton (Warwickshire) and can often be seen around the midlands canal system.

Don’t be afraid to ask, we will do our best to answer any questions you may have.

The owner is a member of the Steam Boat Association of Great Britain, their website is www.steamboat.org.uk where you can find further details of the Association.

Adamant is also listed in the Historic Ships Register, their site is www.nhsc.org.uk

P E Martino 2006