Dan,

Bill tested a planing hull once and as a result he decided not to use this feature in his designs.

In his post he described his test, noted that it was limited and that the idea could be put to work, pending further development and tests. He even offered suggestions on how to develop it. He is not bashing a feature only because it didn't work once.

Compare this to the other designer who tested foils once and now says that he doesn't use them because they didn't work at that time.

This is true, but not the whole truth. He tried only once, had limited experience with foils, probably did not have the resources for further experimenting, was not aware about relevant ressearches on the subject, etc. - all this is ommited.

The difference is that Bill told the truth with great simplicity, without fear of this affecting the sales of his designs, with genuine interest in the development of faster boats.

The other designer simply skiped those details, in my opinion only because it could hurt business.

Bill's posts on theoretical issues tend to be those of a scientist: totally unbiased.
The other guy's are those of an educated salesman: correct but partial or biased.

That's why I affirm that Bill's post says a lot about his credibility (no dictionary now).

Cheers,