According to the French newspaper Le Figaro, Nargeolet had expressed skepticism about the Titan's safety, telling a former colleague that he "didn't have total confidence in this submarine made of composite materials."
Part of the reason for Nargeolet's hesitancy was the Titan's relatively large porthole, which is two feet in diameter. While this feature makes it easier for passengers to get a good look at the Titanic, it represents a potential point of failure in a vessel that has had to endure pressures of nearly 6,000 pounds per square inch.
"He was a little dubious about this new technology but, at the same time, intrigued by the idea of piloting something new, a bit like being a test pilot," his former colleague Michel L'Hour told Le Figaro.