Saturday, 21 January 2017

Brunel's S.S. Great Britain

Occasionally my interests in engineering and my maritime history hobby intersect, as they did when I visited Bristol in 2006, home to two monuments to the genius of Civil and Mechanical engineer Isambard Kingdom Brunel. One is the Clifton Suspension Bridge, of which I have previously shown some photos here. The other is the S.S. Great Britain, which is preserved at a museum there.

The 3,400 ton S.S. Great Britain viewed from the port stern. My lens at the time wasn't the widest, so I couldn't fit her all in.
Here is a picture of a model in the museum to give an idea of her size. Not sure why I am getting the evil eye through the glass case.
Built in 1845, she was the first ocean-going vessel to combine an iron hull with steam propulsion driving a screw propeller, and at the time was the longest ship in the world. She was also provided with auxiliary sail power, and indeed was converted entirely to sail later in her career. After reaching the end of her operational lifetime, she then spent around 86 years laid up in the Falklands, and was scuttled in 1937, before being returned on a barge to Bristol after 1970 where she was restored and remains to this day.

Looking aft along the port side.
The S.S. Great Britain is actually on display in the graving dock within which she was built.

Great Britain looks out over a portion of Bristol Harbour from her graving dock.
Looking out over the bow.
The ship's wheel.
Looking forward along the deck.
Looking aft.
Spending so many years in a salt water environment has taken its toll on the ship's hull. Even after the graving dock was drained, the moisture in the air of the graving dock allowed corrosion to continue, and it was determined (as I recall) that salt had bound to the iron in the ship's hull. Conservation measures, in the form of a glass roof over the graving dock interior and de-humification equipment both in the dock and within the ship's hull, were installed to preserve the ship.

The caisson that seals off the end of the graving dock from the harbour outside.

Looking aft from the ship's bow. Part of the de-humidification system's ductwork runs along either side of the keel.
Looking forward along the port bow.
A close-up of the ship's plating.

Another plating close-up, this time showing some of the holes in the hull.
In many locations, you can actually stick your finger through the hull, as this man is doing.
Approaching the stern.
A replica of the ship's original screw propeller. It was deemed unsatisfactory, and was replaced by a 4-bladed model.
The rudder and propeller.
Rudder and propeller.
Later in the ship's life, possibly when put on the run to Australia, Great Britain was operated primarily under sail for economy, only resorting to her machinery when the wind died. Propellers create considerable drag when a ship is under sail, so the propeller was mounted on a lifting frame that allowed the propeller to be raised when the ship was under sail, and lowered and re-coupled to the propeller shaft when it was necessary to run the engines.

A working version of the lifting frame, with what looks like an original rudder, is housed in one of the nearby museum buildings.
The ship was originally built as a liner, and as such the interior would have been nicely finished, some of which has been recreated in the restored ship. Later refits increased the passenger capacity, presumably at the expense of passenger comfort.

The skylight above can be seen in the photo of the ship's wheel earlier in this post.
The ship's machinery is recreated within, and was designed especially for the ship by Brunel himself.

Great Britain's machinery.
Pistons from the crank shaft down to the steam pistons.
The large wheel on the top, installed on the ship's crankshaft, drives the series of chains that in turn drive the ship's propeller shaft at the bottom of the photo. The chain drive arrangement was replaced in later years.

Ship's interior looking forward.

I found the ship and museum to be very interesting, and well worth the visit if you are ever in Bristol.

As a final note, another ship (also worth a visit) moored nearby when I was in Bristol was the Matthew, a replica of John Cabot's vessel from his 1497 voyage from Bristol to Newfoundland, probably Bonavista or St. John's.

A replica of John Cabot's Matthew.
This same vessel actually sailed the Atlantic in 1997, and as I recall I visited her that summer in Shelburne, NS. While working a summer work term for the Canadian Hydrographic Service at BIO, we got to sign a nautical chart that was to be given to the crew. In addition to this ship, there is a second replica of the Matthew in Bonavista itself.

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