Books like The Riddle of the Sands
Erskine Childers
The Riddle of the Sands is 301 pages, about 5 hours 31 minutes at 250 words a minute.
12 books to read next
How long each takes
For Your Eyes Only 4.4 h 
Casino Royale 3.5 h 
Tinker Tailor Soldier Spy 6.8 h 
Thunderball 4.8 h 
Storm Warning 5.1 h 
Assegai 8.9 h 
Mr. Midshipman Hornblower 4.7 h 
On Her Majesty's Secret Service 5.3 h 
Diamonds Are Forever 4.5 h 
The Human Factor 5.8 h 
Captain Blood 6.5 h 
The Sea-Hawk 6.7 h Bar height shows length. Estimated at 250 words a minute.