Mike the brakes on a PBY are very powerful and need to be applied very carefully or you will rip the tires right off the thing.
The laws of physics dictate that to stop an object in motion requires less force as the weight of said object is reduced....my decision to dump ten thousand pounds of fire retardant was based on that simple law of physics.
The following was not my most pressing worry at that point in time....
as the weight leaves the aircraft, the effectiveness of the brakes is further reduced
Maximum braking is achieved just prior to the wheels locking up.....I had enough experience on type to ensure I did not lock up the wheels during the time I was bringing the thing to a complete stop, therefore an empty airplane will stop in a shorter distance than a fully loaded one.
Empirical evidence would indicate that the decision to reject the take off was sound.
Ergo my advice to think before acting is also sound advice.