Liner Speeds Olympic Mauretania & Leviathan

[Mark Chirnside]

An issue recently left me pondering.

It regards the speed of liners, both their “designed” or service speed and their maximum speed in service, or the maximum speed that they are able to attain for a short period. I have several examples of liners greatly exceeding their service speeds and wondered if anybody could provide any insights.

Firstly, liners regularly exceeding their “intended” service speed:

• Mauretania maintaining for seventy-seven crossings an average speed of some 25.5 knots
• Olympic maintaining general averages of 21.8 knots on Westbound crossings and 22.5 knots on Eastbound crossings, throughout her life
• Leviathan, ex. Vaterland, maintaining during her 1927 voyages an average speed of 23.3 knots

Now, comparing their service speeds to their actual usual average speeds:

<table border=1>[tr][td]Liner[/td][td]Service speed[/td][td]Average speed[/td][td] Flat-out speed [/td][/tr][tr][td]Mauretania[/td][td] 24.5 knots[/td][td] 25.5 knots[/td][td]28 knots [/td][/tr][tr][td]Olympic[/td][td] 21 knots[/td][td] 21.8 and 22.5 knots[/td][td] 24.5 to 25 knots [/td][/tr][tr][td]Leviathan[/td][td] 22.5 knots*[/td][td] 23.3 knots[/td][td] 26 knots[/td][/tr][/table]
*N.B. The Shipbuilder stated 22.5 knots as an intended service speed, but other sources state a speed of 23 knots.

It seems to me that no attempts were being made for the liners to average higher speeds than intended, but the engines were just run at the designed speed, giving a higher average speed than expected. I know designers made sure that there were adequate power reserves to maintain the intended service speeds in many weather conditions, but does this explain the higher averages? If these vessels had been run at their utmost speeds, I believe Leviathan for example could have achieved an average crossing of 25-26 knots.

And, for the main issue: liners reaching considerably higher speeds than was ever expected:

• Olympic apparently attaining 27.8 knots in July 1922 (though I have my doubts)
• Majestic (II) attaining 27 knots for five hours in the mid-1920s
• Mauretania reaching 31 knots in the early 1930s

I am assuming that in each example the liners were running flat-out, but nevertheless the speeds seem too high. All I could think of by way of explanation is that these speeds are aided by strong winds and currents, but is this a viable explanation?

And, any thoughts regarding the higher average service speeds?

I would be grateful for any contributions. For the next few days I will not have internet access, but I will get back after that.

Best regards,

Mark.

 

[David G. Brown]

Mark -- just an observation regarding why ships may have been faster than their "design speeds." I have noted that the propellers installed on ships between 1890 and 1900 are only marginally improved over those of John Ericsson. After that, there seems to be a quantum leap into modern propellers with regards to blade shape, twist, and cross section. Since all motion of a steamship originates with the propellers, even a small improvement in their design would produce significant results in higher speeds and better fuel consumption. Can't say that I'm right...wish I had the time to do some serious research. But, I do know that marine propeller technology benefitted from what was being learned about aeroplanes.

-- David G. Brown

 

[Michael H. Standart]

Mark said; "Olympic apparently attaining 27.8 knots in July 1922 (though I have my doubts) "

You and me both. Would the hull have even been capable of doing so? Even with improved propellors, length to beam ratio remains the same and so does the resistance that comes with it.

Any idea where does this claim come from?

Cordially,
Michael H. Standart

 

[Mark Chirnside]

Hi Dave and Mike!

Thanks for the responses, and sorry for this rapid reply.

Since all motion of a steamship originates with the propellers, even a small improvement in their design would produce significant results in higher speeds and better fuel consumption. Can't say that I'm right...wish I had the time to do some serious research. But, I do know that marine propeller technology benefitted from what was being learned about aeroplanes.

Thanks for the ideas/suggestions. It's a good area to explore -- we always hear about vessels having propeller modifications during refits, etc.

"Olympic apparently attaining 27.8 knots in July 1922 (though I have my doubts) "
Would the hull have even been capable of doing so? Even with improved propellors, length to beam ratio remains the same...

The claim apparently came in the press, and a number of first class passengers I know stated such. However, I found out recently that Olympic's much-cited November 1921 crossing was *not* her fastest; it was the quickest, as in days and hours, but she later clocked-up even faster averages, in 1924 and 1926, to name two examples. However, as her total westbound half was well over 22 knots for the whole trip, it was likely her fastest *round trip*.

But back to the exact topic: Olympic's July 1922 crossing home averaged 22.6 knots, a little higher than usual, but certainly not with the ship at full speed. The average might have been raised by a brief run flat-out. Olympic acheived 25 and 25.1 knots in 'emergency' situations, pre-World War I; in actual service she could work up to 24.2 knots with a favourable current, but not really straining. Let's assume in July 1922 she was coming home, and had worked-up to 24.2 knots: how could she attain 27.8 knots?

Well, in an 'emergency' attempt she could do 25+ knots, but there was no reason to make such an attempt in this instance. Boredom? Say the current was better than usual, two knots (yes, freak circumstances) -- that takes her to 26.2 knots, plus a strong wind in her favour -- to 27 knots? Captain knows favourable circumstances may never be repeated -- let's take the ship really flat-out for a few hours -- to 27.8 knots?

Could these circumstances, strong wind, current, full speed, raise the speed enough? The problem is, 27.82 knots is as exact as measured in those days -- okay, perhaps a bit out, but not three knots. Now, Mauretania attained 27.75 knots on the measured mile in 1907 -- but in 1929 for four or so hours she made a dash at 29.7 knots; in 1933 she ran at 32 knots for some time. How the difference there? Yes, some engine work, but that isn't enough. Could freak conditions have raised her speed, and Olympic's? Any opinions welcome.

Best regards,

Mark.