An instance of good straight racing between individual vessels occurred in 1866 with Taeping docking 20 minutes ahead of Ariel , the Serica being a few hours later on the same tide. The times were 99, 101 and 99 days respectively from Foochow.

The 1867 race was remarkable in that seven ships, Whiteadder, Ziba, Taitsing, Black Prince, Yangtze, Chinaman and Deerfoot arrived on the same day in London after 123, 121, 120, 119, 117 and 115 days from Foochow, with Deerfoot 125 days from Whampoa.
1868 saw Ariel, T aeping and Sir Lancelot leaving Foochow together , followed the next day by Spindrift, and arriving in London 97, 102, 98 and 97 days later.
In 1872 Cutty Sark and Thermopylae left Shanghai together, Thermopylae arriving in London seven days ahead, due only to the Cutty Sark having lost her rudder and having to finish with a jury one.

  A great deal of controversy had been aroused in the past as to the actual speed of the clippers, and sailing ships in general. The methods used for computing speeds varied from a patent log to the old style log and glass, and it has been stated that the inaccuracies of the latter allowed exaggeration; but one could also logically say it may have underestimated speed as well.
Lord of the Isles was reputed to have reached 18 knots, Spray of the Ocean 17, and Cutty Sark 17.5 knots with a day's run of 363 miles. Ariel and Thermopylae did 16 knots, and 14 to 15 knots was quite usual with many clippers.
  Speeds of 21 knots have been claimed and disputed by experienced mariners, in the correspondence columns of seaport newspapers at various times. Donald McKay specified his Sovereign of the Seas as being a 21 knot ship, so it must have been a reasonable figure for such an experienced designer to forecast it. In recent years I was informed by an officer of the USS Eagle that during a gale the ship had logged 21 knots measured by the most modern recording apparatus, and this was in a fairly full-Iined vessel with a high deck structure and a feathered propeller. The sailmaker of the three-masted steel ship Brenda of 1891, a full-bodied cargo carrier, used to tell me that on a number of occasions she logged 19 knots.
  Captain Clark, in his book The Clipper Ship Era, records the American Lightning and the James Baines Blackball liner on the Liverpool-New York run logging speeds of 18! and 17 to 21 knots. These Donald McKay creations, together with his other noble ships, were probably the finest and fastest sailing vessels ever built. The whole value of the clipper ships, however, lay not only in their ability to attain high speeds under ideal conditions for short periods, but in being able to move at all when most other vessels were becalmed, and in maintaining good average speeds for