Early Fleet

Three island tramp steamers were built in vast numbers in the late 1800s and early 1900s. The engines were installed in the centre section, along with most of the accommodation. This was to assist with the stability of the vessel since double bottoms and water ballast tanks in general hadn't really gained currency.

When first built, most of the type had an open bridge on an exposed platform. This was later modified to the raised enclosed type during the 1920's.

Rubens, the first ever Bolton's vessel, was built of iron and powered by a compound engine probably supplied by a low pressure iron boiler running at a pressure as low as 10 psi.

But subsequent steamers, Rembrandt onwards, were to be powered by triple expansion engines supplemented, in later years, by LP turbines.

Triple expansion engines recovered much more of the steam's energy by expanding it right down to atmospheric pressure (and later below when utilising condensers). This, however, was only possibly by the advent of quality cheap steel in the late '80s, allowing boilers to raise steam at around 160 psi and upwards as opposed to the low pressures that the iron boilers could safely achieve.

Also more was being understood about the properties of steam. Superheated dry, as opposed to 'wet' steam was beginning to be the domain of the engineer as well as that of the scientist. The technology of a kettle wafting steam from boiling water into a tube enclosed at one end and with a moveable seal at the other had been and long gone. But the absolute energy within 'drier' steam was only just being realised with the triple/quadruple 'E' (and later, turbine) and it was proving to be a complete winner in terms of output and efficiency..

This, together with the newly opened Suez Canal (Nov 1869) brought India and the Far East much 'nearer', India by a half and the Far East by a quarter. And for the first time, in the mid '80's the tonnage of UK registered steamers began to outweigh that of sail.

Steamers now using this shorter route obviously used less coal as opposed to the old Cape route, and as more frequent bunkering ports became available throughout this new route, it was all good news for the steam ship owner.

And so a round trip for early Bolton vessels would be outbound to the Mediterranean with Welsh coal for the new bunkering stations, and inbound with hemp, rice, grain or cotton seed from the Black sea.

1st Hand

The greatest of care together with undivided attention is necessary when feeling the bearings of a running engine. Before feeling crankpin bearings the path of the moving connecting rod should be noted. The palm of the hand is then held with the fingers pointing in the same direction as the path of the big-end bearing and slowly brought nearer so that the moving bearing lightly touches it in passing. It is advisable at such times to roll up overall sleeves and to wear no rings on the fingers. If the extremities of the big-end bearing are to be felt by the side of the hand, the fingers should be held pointing in the same way as before, the small finger of the hand being brought into contact with the moving bearing.

Admiralty Steam Reciprocating Engine Manual

Vessels with no picture are suffixed 'np' in the navigation bar.

While the same named vessels are differentiated here by their sequential numbers they were never christened so, and were named without a number.