“Smooth seas make poor sailors”

“Smooth seas make poor sailors” is a nautical proverb that dates to at least 1863. The saying means that smooth seas don’t provide sailors with a proper challenge or test to make them into better sailors.
 
The financial proverb of “smooth seas make poor sailors” was used during the economic storm of 2008-2009.
   
Other water-related financial sayings include “Anyone can steer the ship in calm waters,” “A rising tide lifts all boats” and “When the economic tide goes out, you find out who is swimming naked.”
 
   
Google Books
December 1863, The Ladies’ Repository, pg.736:
Smooth seas make very poor sailors.
 
Google Books
Reading Made Easy for Foreigners
Second Reader
By John L. Hulshof
New York, NY: Hinds, Noble & Eldredge
1909
Pg. 86 (Wise Sayings):
Smooth seas make poor sailors.
   
MarketWatch
Re-Framing the Recession for 2009: A Three Point Plan
by Small Business Authority Jay Goltz
Last update: 8:11 a.m. EST Dec. 16, 2008
(...)
A long time believer in the African proverb that smooth seas make a poor sailor, Mr. Goltz explains how to navigate the current rough waters in three key areas: your customers, your product and your people.
 
iStockAnalayst
Words from The Wise
By: Financial Armageddon   Wednesday, February 11, 2009 11:59 PM
(...)
There’s an old saying, “Smooth seas make a poor sailor.” Once you’ve weathered a few economic storms, you learn how to adapt.