The following is correct by my reckoning:

Hello List,
I have come up with
1.-Kaiser Wilhelm der Grosse
2. Deutschland
3. Kronprinz Wilhelm
4. Kaiser Wilhelm II
5. Kronprinzissin Cecielie
6. France(1912)
7. Lusitania
8. Mauretania
9. Titanic
10. Olympic
11. Aquitania
12. Brittanic
13. Windsor Castle(1922)
14. Arundel Castle

-Bob

The last two are often overlooked; and were converted to two funnels in
1937-38 refits.
This question arose because I saw an ad for a book on the four stack
liners, the ad stating that only 14 four stackers were built, so I had to
look them up myself…. I found them in Kludas vols. 1&2.

The answer to Trevor Kenchington’s question, as to which had 5 funnels,
would be the very first entry in Kludas, the GREAT EASTERN.

-Brooks