Rough rule of thumb for max lengthening of an aluminum hull?

[gonzo]

The cost/benefit analysis is honestly very complex, variably-specific to individual areas, and highly counter-intuitive for those who do not have experience with frontier medical needs and availability. Our costs will not be small, but the fee we would charge to break even is significantly cheaper than what a government would spend on a year of transporting patients from areas that do not have health care.

That is very evasive. There is nothing counter -intuitive about cost/benefit analysis, but the opposite. It is a tabulated comparison of several alternatives. We do that for large projects. Sometimes they are after a disaster and the response has to be as fast as possible. For example, three winters ago the whole northern area of Nebraska had ice damage throughout. The ice sheet was up to 4 FT thick and moved like a glacier. Almost all the bridges were down and most of the roads. Bulding were also destroyed. We did the initial damage inspection, focusing on underwater, streambed and stream boundaries. That report was the foundation for the cost/benefit analysis on repairing the infrastructure and future modifications to prevent the extent of the damage. Any engineer is familiar with that kind of analysis.