SS Great Britian, 1843, 322feet, 1,000 HP steam with sail assist

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Well-Known Member
HMEM Supporting Member
Mar 8, 2019
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Charlottesville, VA
I recently had the good fortune to travel to the UK, and being from the US, everything there seems older than dirt (in a good way). Two of the technological highlights of the trip were a visit to the Bluebell Steam railway in Sussex, and the SS Great Britain in Bristol. We went with our daughter, and our son-in-law, who is from Sussex, and he took care of a lot of the planning of attractions to see. He knew what I liked and hit a home run when selecting these two destinations. I can't thank him enough!

The SS Great Britain was way ahead of its time. Built for ocean travel in 1843 in Bristol, England, it was 322 feet long, iron-hulled, steam powered, but with 5 huge masts for sail assist. It eventually sailed over a million miles between England, New York, Australia, and other places. It's configuration and use changed over the years, and it was eventually scuttled in the Falkland Islands in 1968. But then it was re-floated, at great expense and effort, and returned to Bristol England, put back in its original drydock, and restored as a museum.

There was a model of the steam engine in the museum, but what shocked me was the fact that the original steam engine had been remade such that it moved/rotated in a demonstration type of mode. Amazing in its massiveness. It's a bit hard to tell from my pictures, but the engine is a 4 cylinder, side-by-side, inverted V-twin. Each cylinder is about 88" bore (2.23 m) x 72" stroke (1.83 m) operating at 17 rpm under only 5 psi of steam. That is what I was told by one of the older guides on board the ship. The huge crank was actually turning so you could get a feel for the power. There was a chain drive to overdrive the prop shaft at maybe a 5 to 1 ratio (my guess) for 85 rpm for the prop. Using a prop was a big deal in those days because everything else that large was side paddle wheels, which didn't work well in the ocean.

Here are some pics I took. They don't do the ship justice, and the book I got there is much better, but you can look online for better pics if so inclined.

Me at the helm, facing the stern (doh!) for a photo op. You could climb up the rigging for a small fee, but I figured the funeral expenses would make it a bad idea.

Main crank for one of the pair of V cylinders, and bearings. Just to get a sense of the scale, the crank radius is 3 feet.

The other main bearing. I wonder who fills the oil cups while under-way?

This is looking down from the level of the crankshaft. Closest to you is one of the main conn rods, next is the smaller diameter conn rod to the steam valve box, and in the rear is the other main conn rod to complete the V layout. Down in the bottom rear you can see one of the huge 5 psi steam cylinders.

Crankshaft above, main conn rod directly ahead and slightly above, cross head directly in front, and the piston rod heading downward to the cylinder.

Here is a good view of the cross head, and the top of one of the cylinders (2.23 m bore) that appears to be wrapped in wood like a barrel, I guess to give its iron lining additional strength. That is a 250 HP cylinder. In 1843. WOW!

This is the prop that was cobbled up for the restoration. The prop made it work it rough seas and made a lightning speed passage from England to Australia in only 60 days!

And finally, here is a random, more modern, steam cylinder and flywheel laying in the museum yard. This old junk is all over the place, LOL.
What a visit!

P.S. Believe it or not, I have been working on my diesel model a few minutes at a time, and will have something worthwhile to post soon.
Impressive :)

I've seen an hour long documentary on that ship a few times. Probably on youtube. It's worth looking for if you want to know more about the radical design decisions that were made at the time.
Yep, that propeller was radical for the day, and for good reason; there was not a lot of proof of them working successfully.
And they had a great deal of trouble working out the propeller for that boat, but figured it out in the end, and made the right choice I think from a design standpoint.

I wonder about the original direct-acting engines, and and not sure exactly what format they were in, but I suspect it was one of those pancake type steam engines.

And I keep seeing 4-cylinder, but I doubt that serioiusly.
I have never seen a big oscillator in a ship that was not a twin.
There would be no reason for a 4-cylinder, unless they wanted a smaller package or something.

The current engine looks like a twin cylinder.

Interesting boat and engine.


And I keep seeing 4-cylinder, but I doubt that serioiusly.
I have never seen a big oscillator in a ship that was not a twin.
There would be no reason for a 4-cylinder, unless they wanted a smaller package or something.

The current engine looks like a twin cylinder.


You must have missed it somehow, because it is definitely a 4 cyl now, and originally, although it went thru several config changes over the years.

I took the pictures and videos myself, of the model in the museum, and of the actual full size engine replical below decks.

Ive attached a video that shows the 4 cyl layout a bit more clearly.
In the video, the first view is an end view of the model in the museum (with the yellow structure and 4 yellow cylinders), in the fore-aft direction, in line with the crankshaft, showing the inverted "V" configuration.

The second view is taken perpendicular to the keel, and shows the two banks of "V"s. You can also see the chain drive with the big sprocket at the top to overdrive the prop shaft which is down below.

The 3rd view is of the crank for one of the banks of the "V" on the real engine below decks.

The 4th view is of the actual chain drive that is situated between the 2 banks of cylinders.

Yes, definitely 4 cylinders.

The screw you thought was cobbled together. But My understanding (often incorrect?) was that was how I.K. Brunel designed his first screw-propellers. ("Screws" are fitted to ships as they form a screw pattern in the water - at Brunel type speeds. "Propellers" are fitted to aeroplanes in t he UK).
Basically, he did not use cast screws at first, as there was a lot of experimentation with engine speed, screw speed, pitch at various points on the radius of the blades, etc. to develop the most efficient form of screw. Fabricated screws were cheaper and easier to adjust until the technology had matured enough to use cast screws.
Read also about how he did a tug-of-war between to ships - otherwise identically powered, but one with paddles and the other with a screw. Development of the Screw Propeller - Shipping Wonders of the World
I hope this clarifies my view of the "cobbled-together" screw to Brunel's design.
Interesting history of the screw on the SS gb. That does sound reasonable about modifying a smaller screw to handle the size required of the biggest ship of the day. Brunel was quite a brilliant risk-taker, but only when the odds were in his favor.

Regarding the article about the development of the screw propeller, I love that sort of geek stuff, and my wife will give me a good natured roll of the eyes and say, "I bet you are going to go watch something exciting like, " The history of ball bearings."
Well......... Uh....... Yes actually.
Wonderful to see such joyous reviews of the museum in the town that’s been my home since 1996. The work that has gone into preserving the SS Great Britain is astonishing and gives us a real insight into the development of steam ships. Not far away is the replica Matthew, the small ship that took Cabot to the New World in 1497 and has sailed the same route again in 1997. I was there, witnessing the start of that voyage under the Brunel suspension bridge….. in the sheds next to the Great Britain began the development work on Bloodhound, the car that aims to break the 1,000 mph speed record. Quite some stuff on my doorstep!
So now I am curious about the engines used in these great ships, and the more I look, the more it seems I lack knowledge for.
The Great Eastern apparently had sidewheels and a screw propeller?

I guess like the Titanic having two reciprocating steam engines and a single turbine; a hybrid approach to the power plant.

So it appears that the Great Eastern had a direct-acting screw engine of 4,886 hp, which powered a propeller (basically what I call a "suitcase" engine), and a 4-cylinder oscillating-type engine to drive the paddlewheels of 3,411 hp.

I had assumed (incorrectly) that there was a clean transition from the paddlewheel ship with oscillator engines, to the screw propeller driven ships with engines that were not oscillators, but that was not the case.
I had also assumed that all the big oscillator engines in ships were two-cylinder. (wrong again).

The big steam ships were much more complex than I realized.

A nice laugh is always a good thing!

Bristol seems like a nice place, and Brunel certainly has left his mark. We actually saw the Clifton suspension bridge first, walking across it. I does have a nice solid feel, and way above the bottom of the gorge. Then, when I saw the big chain drive on the SS GB, there is the obvious connection to the links of the suspension bridge. Interesting seeing an unusual engineering technique carried from one discipline to another. But I have to ask about the tidal flow in the Avon. While on the bridge, the Avon must have been very close to low tide, although the water was still flowing toward the sea. It almost looked like you could have walked across it if it weren't for the mud. But knowing that ships can come up the Avon to Bristol, what is the difference in water level at low and high tide? I saw pictures of the SS GB being towed under the Clifton bridge and might not have believed it otherwise.

I re-read your post, and now, after visiting the UK, and having a slightly better understanding of English understatement, I see that my haphazard use of the terms " cobbled up, propeller, and screw," was inappropriate, poorly thought out, and maybe even a little offensive. Please accept my apology (even though I will most surely make similar faux-pas in the future.) 🤣

Lee Webster,
My wife is facebook friends with a few people in Cornwall. No offense intended, but she says you can be a sensitive lot.
Wow, I am messing up the international etiquette all over the place! (Damn stupid Americans, LOL)

Several times, huh? Would a therapist call that "normal."

It's doubtful you'll find too many gas stations in the middle of the Atlantic, either.
Please tell me what an oscillator (steam type) is. (edit) I thought those all disappeared when the solid state ones hit the market.
All of this old technology, on such a huge scale, like trains and ships, does boggle the mind. Maybe the lack of modern-day distractions allowed them to stay focused on the task-at-hand.

Thank you all for indulging, or some might even say, "enabling", my ramblings.
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The tidal range in Bristol is between 12 to 14 metres (40 feet to 46 feet) so there's plenty of depth for even quite large ships. It's th second highest tidal range in the world - beaten only by the Bay of Fundy with up to 53 feet. The main navigational hazard was the bend between Avonmouth and Bristol where longer vessels could go aground - if that happened on an ebbing tide the ship could break its back.
Hi Lloyd,
No need to apologise for being "a Colonial", with different use of the original English. In fact you could say "American" is simply a more progressive form of the English language, and what "parent" could ever be offended by their "child" being progressive and successful - as the US has become in the last 400 or so years? The banter helps keep me smiling - I hope I don't offend anyone in the process!
As to tidal range - I grew up (physically - I am still a stupid child in my head!) in Newport, or more correctly, the New Port of Caerleon. A roman fortress built about 2000 years ago to keep the Welsh in and tax everything that crossed the border between Roman civilisation and the Welsh - well Welsh anything? (The Romans were more invaders we had to suffer - who brought us straight roads, flush toilets, Latin laws and Civil organisation - Akin to a Federal government! Who needs all that?).
Caerleon Roman Fortress and Baths | Cadw (
At Newport, the Normans built a castle - on the border between England and Wales.
Newport Castle - Wikipedia
The castle was at the lowest fording point, at low tide, when the water was less than 4 ft deep, so a horse and cart could get across the rock paved road - A roman legacy? - then be taxed at the toll gate in the castle! (The Danes taught us taxation! - then Income tax! -"lovely people" but thankyou - not.). At the dock gates in Newport, the rise and fall of tides could be as much as 44 feet. (Maximum high tide recorded in the tide tables for Newport is 13.1 m and a minimum height of -0.4 m . ) As the tide comes in over the mud flats, (about 1 1/2 miles), it runs as a wave about 10mph.
But when the tidal waters travel above Newport and Bristol, past the mouth of the river Wye, the tidal wave develops as much as 10 ft high and runs at up to 15mph. - for Miles! - Twice a day! (We English call it a Bore - or to help others, a Tidal Bore). Home (
Just a bit of "Engineering"- a railway in the sky? Newport Transporter Bridge:
Transporter Bridge (
Incidentally Lloyd, as you bear a Welsh name - and they are a very proud people - I hope I have not offended you with any of my aspersions towards the Welsh people. They are after all, the remnants of the original Britons, before Angles, Saxons, Norwegians, Danes, French and other Europeans invaded to make us "English"?
And as I am being a bore, as in "an English Bore", I shall sign off.
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