The machinery on board is very similar, on a smaller scale, to that carried on the ill fated “Titanic”, which makes “Shieldhall” a unique link with the past. The following is a brief summary, to find out more, come aboard this wonderful ship and see for yourself.
|Breadth||44 Feet 6 Inches|
|Draught||13 Feet 6 Inches Aft|
Two Scotch boilers, each 12ft diameter and 12ft long, produce saturated steam at a pressure of 180lb/sq.inch. The steam powers the main engines, auxiliary engines, all the deck machinery and a 25kW electrical generator (a diesel generator has been added to power modern navigational equipment).
The boiler is of riveted construction and has approximately 320 firetubes. Fuel oil is forced under pressure to provide an atomised spray which is then burnt in the furnace. Air for combustion is supplied by a single-cylinder, forced draught fan. To improve efficiency, the air is heated by the combustion gases before they exit from the funnel.
For the non-technical: “Shieldhall” has two large, oil fired boilers providing steam power throughout the ship. They are similar, although smaller, than those used on the “Titanic”.
The two main engines were constructed by the ship’s builders, Lobnitz & Co., of Renfrew, Scotland. They are triple expansion engines with cylinder diameters of h.p.15″, i.p. 25″ and l.p. 40″, and the stroke of 30″. Each engine can provide up to 800 horse power to its screw. The normal service speed is 9 knots at 86 rpm. This is our economical speed, although the designed maximum is 13 knots at 120 rpm.
Waste steam from the engines, is ejected to a condenser where it is cooled by sea water passing through the heat exchanger tubes. The condensed steam is held in the hot well before being pumped back to the boilers as feed water.
For the non-technical: Two steam engines drive the ship and to avoid wasting water, the steam is condensed back to water and re-used.
There are 20 steam engines driving all of the original machinery. Modern diesel and electric machinery supplements power and firefighting capabilities.
Other onboard equipment
This is a two cylinder, fixed lap and lead reciprocating steam engine which alters the rudder angle through a rack and pinion arrangement working on the rudder quadrant. Rudder movements are transmitted from the ship’s wheel on the Bridge by hydraulic pumps which form part of the wheel assembly. Control of the steam input is via a control ram working on a closed loop feedback which adjusts the steam inlet valves accordingly.
The for’d windlass and capstan and the after capstan are all operated by steam generated by the main boilers. They are normally used to moor the ship and to recover the anchors. The machinery to launch and recover the lifeboats and operate the cargo derrick, is all Armstrongs patent, i.e. muscle power.
Bridge and Navigating Equipment
On entering the bridge, the first item of equipment that you pass is the engine room telegraphs. These are situated on both bridge wings and by means of chains, relay the required engine movements to the engine room.
Within the charthouse, there is a traditional ships wheel and binnacle. The course to steer can be by reference to the magnetic compass within the binnacle, or the modern gyro compass, mounted on the deck head.
There are various items of electronic equipment which are required to navigate “Shieldhall” from port to port and an item of interest is the Decca Radar set which dates from the early 1960’s and is still operational. It is normally used as a standby to the modern set located on the chart table.