Why Royal Navy constructors bet on G3 speed

Why did senior Royal Navy constructors make bets about the G3 battlecruiser's speed?

Speed trials tested their hydrodynamic calculations, while the small wagers supplied professional rivalry and bragging rights.

The proposed G3 speed wager tested confidence in the constructors' hull calculations. Nelson and Rodney are used as evidence that the related calculations may have underestimated what the G3 hull could achieve. On that interpretation, Goodall would have won. A follow-up gives the stakes as one pound if the Director of Naval Construction won and five pounds if he lost. The discussion treats such wagers as professional rivalry and motivation, recalling that nominal cash bets could end in buying a round at the pub.