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[derekwarner]

Couldn't resist this magnificent image of a working steam tug in another thread today..


So the Tug appears to be in work [tensioned stern line] ........have seen many images of boilers working or warming up with copious volumes of grey coal smoke, and a number images of Naval vessels with dense black clouds of bad oil combustion


Question is ......is this an oil burner with faulty or bad combustion? with the plume to Port & the Captain oblivious to this looking to Stdb 


Derek

[Bunkerbarge]

As this particular Hercules was built for the Canadian Minister of Public Works by Polson Iron Works in Toronto in 1906 she would have been originally built as a solid fuel fired vessel.  Operating in Canadian waters she may well have even supplemented her coal fuel with wood.  She might have been converted to oil fired later in life but your picture looks to be an early one.

Being solid fuel fired the quality of combustion would have been extremely difficult to maintain at anything like an efficient level and, added to that, air registers and forced draught systems were extremely crude, if actually fitted, so thick black smoke was a very regular and accepted situation.  The main problem with solid fuel is the total lack of control over the fuel to air mix, which was why in around the post war years and the 50s many solid fuel marine boilers were modified to burn oil.

[Geoff]

Its also possible that oil spray was added to the coal boiler which was common (particularly in Naval vessels) before full conversion to oil. In general when they are stoking the boiler copious amounts of smoke are produced as full and proper combustion has not yet taken place. Once stoked up the smoke is typically considerably less. As she is towing it may well be she is stoking.


There were a lot of problems with oil firing in the early years as oil was thick and the burners had to be designed from scratch so before full oil burning it was tried out on coal boilers which increased both range and rate of heating to good effect.


Oil boilers were very different from coal and oil as with coal boilers generally the maximum size was governed by the need to clean the grate and remove ash by hand which meant long rakes that a man could handle and therefore the room to use them. Pure oil fired boilers removed this requirement so tended to be bigger and needed less room as no stokers and no need for ash removal.


Cheers


Geoff

[Geoff]

Just to add with mixed firing the oil was sprayed directly onto the coal so various spray heads were tried out and flow rates and oil pumps to see what worked best. The Victorian battleships of 1899 had mixed firing. Nearly always coal but they could spray oil on for extra speed and of course due to its greater thermal efficiency oil increased range.


However how to store it and refuel all had to be sorted out. Early ships had oil tanks deep down and sometimes under the boilers to pre-heat the oil. It was also felt to be a big fire hazard. In fact it was not and in later years it was stored along the sides of the ships as part of the torpedo protection system as the liquid slowed down splinters.


One of the biggest benefit for oil power was the ability to steam flat out for hours and days on end, particularly in conjunction with steam turbines. Coal boilers have to be regularly cleaned of ash and debris to maintain efficiency. Another factor was the quality of the coal - Welsh Steam coal was the best in the world. Poorer coal gives poorer consumption, more ash and more clinker to be removed.


However triple expansion engines were more economical at slow speed so were retained in many civilian ships for decades


Cheers


Geoff

[KNO3]

Very interesting, thanks Geoff.

[steamboatmodel]

One thing to remember about the Oil firing is that the oil would have been Bunker C Oil. This is not like motor oil, but more like molasses. It had to be heated to get it to flow, and would clog nozzles constantly.
Gerald.

[Jerry C]

My shipping company, Blue Funnel Line used residual fuel oil HFO No 6 with a viscosity of 17,000 seconds Redwood Scale. It was kept continuously heated by steam coils. The 3rd engineer was responsible for its care. Ships had a bank of Laval separators to remove water and sand. He was forever cleaning the discs. Main engines were started and stopped and manoeuvred on Diesel. Engines mostly B&W opposed piston or double acting opposed piston 6 cylinder engines. 6 fuel valves in each cylinder and all driven by exhaust gas pumps!


Jerry C.

[SteamboatPhil]

Blimey Jerry, who knew. Question if it the fuel was warmed by exhaust gas heat, how did you start the process from cold. Sorry may seem stupid question but I have to ask

[Jerry C]

Hi Phil, if memory serves, if steam coils failed in a tank the fuel had to be pumped to other tanks and the remainder had to be dug out. Steam provided by separate boiler. The fuel valves (injectors) were driven by exhaust gas (from an adjacent cylinder) pumps. It all worked well and was very economical but the servicing of gas pumps and injectors was continuous. We had 12 Chinese greasers to assist the 3/E. The newer ships (super Ps) had Sultzer Main engines which might not have used HFO but I’m not sure about that. Either way it was a brilliant shipping company to work for and we were treated as family by the owners. My wife accompanied me on our honeymoon voyage, joining in Vancouver for an around the world voyage, west coast Canada, States, Venezuela, US gulf ports, east coast ports up to Newfy St Johns, across  Atlantic to Suez, Djibouti (bunkers) Malaya Singapore Bangkok Hongkong where she had to have her Gaul bladder removed. 2 weeks convalescing in HK then long flight home via Bombay, Tehran, Vienna and London. To get her airfares paid we were meant to do a double header and missed out on Philippine’s and Japan but the company waived the fees. She accompanied me on quite a few voyages including west Africa.
Really memorable times for her.
What a great life we’ve had together. Hoping to return to uk after nearly two years in Oz due to covid.
Jerry C.