NZFMM 1993 Auckland Convention page 16 of 17

Paddle Steamer Engine with feathering blades by David Wall

Notes on the Model provided by David Wall

Marine Engine And Boiler Room

This type of engine and boiler arrangement was popular in the closing years of the 19th century to propel excursion vessels and tugs.

Engine

This is a direct acting diagonal compound type.  Steam is admitted to the high pressure cylinder via a piston valve and to the low pressure cylinder via a slide valve.  Both valves are activated by Stephenson's (reversing) valve gear.   This type of engine normally ran at about 45 to 50 R.P.M. and was controlled by the engine stop valve to admit steam to the high pressure valve chest and a manually operated reversing gear to lift and lower the expansion links.

Boiler

The boiler is a single ended, three furnace, scotch type working at a pressure of 140 lbs/sq".  Boiler fittings include a safety valve, inspection cover, main stop valve, whistle and auxiliary valve, two non return feed water valves, steam pressure gauge and valve, two water level gauges and scum and blow down valves.

Funnel

This is a natural draught outer cased type fitted with an uptake damper, whistle and waste steam pipes.  It would be braced to the hull with four or more wire stays.

Paddles

These are fitted with feathering floats to reduce the impact and drag as the floats enter and leave the water.

Ancillary Equipment

The remaining engine/boiler room fittings include the surface condenser, air and circulating pumps, two Weir type feed water pumps, stoke hold ventilators, coal bunkers and an engine room telegraph repeater.  Also fitted is the steam induction pipe leading from the boiler main stop valve to the engine stop valve and the education pipe leading from the low pressure valve chest to the condenser.   Engine and boiler room access ways are also fitted.  The engine and boiler room would have been illuminated by oil lamps.

Part 61