When Hurricane Katrina mangled its Louisiana coffee-roasting plants in 2005, Procter & Gamble Co. chose a nontraditional route to getting its sub-rosa systems running again. In addition to tapping into its own vast force of experts, it turned to outsiders.

Within hours, three retired engineers were en route to New Orleans, joining a P&G team to perform triage on the woebegone facilities. Together, they got fresh water flowing; in two months, the lines were up and rolling.

The engineers’ origin: YourEncore, a Cincin­nati- and Indianapolis-based collaboration of almost 6,000 retired scientists and researchers. The brainchild of P&G, YourEncore—now a private company—works with dozens of such corporations to firefight needs ranging from natural disasters to package design.

Today, YourEncore is a significant component to, and product of, P&G’s flourishing Connect & Develop program, launched in 2000 to goose up innovation by linking P&G’s own talent with outside experts.

“We’ve discovered we have virtually hundreds of ways that retired scientists and engineers can help P&G,” said Karen Kreutz, section head of Connect & Develop’s R&D. “They’ve been continuously rising to the challenges that P&G sends their way.”

YourEncore’s performance recently earned it an “enabling partner of the year” award from P&G.

But YourEncore experts service more than P&G. Since its founding, YourEncore helped complete roughly 2,000 projects for more than 30 companies. And in 2008, it expanded its network to Europe. But P&G remains its largest client, accounting for 600 projects.

It operates as an online “innovation community,” where technical virtuosos are matched with corporate needs. Often, these are highly specialized needs that require the retirees to collaborate with the client company’s own staff. Sometimes, the clients are suppliers that seek out P&G retirees specifically—to help them better prepare to do business with the consumer products maker.

“From Procter’s perspective, their belief is that some of the best-found ideas are outside of the company,” said Ali Dibadj, an analyst covering P&G for Sanford C. Bernstein in New York. “That has been part of their process for years: to be more efficient in R&D.”

Which explains the genesis of YourEncore. P&G hatched the idea back in 2003, as its Connect & Develop program was yielding its earliest crops of fruit.

P&G discovered much promise in the minds of retired scientists and engineers of the world and looked to see if other companies would as well. Many—including Eli Lilly and Boeing Co. —said yes. Soon after, General Mills joined too.

Boeing alone has recorded 65,000 project hours with YourEncore—in its commercial and defense businesses—as well as R&D activities, said Lynne Wenberg, a senior manager at Boeing Research & Technology. Boeing has tapped its own retirees to mentor and coach employees and has used retirees from other organizations to help with proposal work and process improvements.

“We’ve used some experts from P&G, which you would think is a very different company from Boeing,” Wenberg said. “But we found ways to leverage their expertise, and vice versa.”