Maybe the TV age is too late for such developments, but I was hoping you'd write your own rules based on your general understanding of the game which might over years diverge into a uniquely Brazilian flavor of American football, and possibly, given long enough (generations), an entirely new kind of football. After all, as long as you don't play with foreign touring sides or use imported officials, your rules don't have to match anyone else's in any particulars.
If you want an American football rule book that reads very easy (at least in English) and is fairly simple to remember & administer, see if you can obtain one of the National Federation of State High School Association's from the late 1970s or circa 1980. (If you want one that's just as short or shorter, but largely because it
leaves much to interpretation, get one from the Canadian Football League from that same era.)
All of the US American codes derive from that of the NCAA. The Federation simplified theirs starting in the 1940s, but after 1980 began complicating it again. The NFL just kept complicating theirs, although I understand they've been doing some comprehensive rewriting lately to rationalize it.
You might want to make certain changes just for convenience's sake. Other than these beach "fields", you might want to use rugby pitches with their existing goals. Then you have a decision to make, providing the rugby field is at its maximum allowable dimensions:
- Make its goal lines your goal lines, and have your goals on your goal lines.
- Make its goal lines your end lines, and have the distance between your goal lines equal 110 yards minus the depth of 2 end zones, or 90 yards if you want to have 10 yards deep end zones.
- Use USA lengths for field of play and end zones, and have goals stuck in the center of each end zone.
Any of the above saves you having to erect goals on fields you'll occupy only temporarily, provided the rugby field has permanent goals.
BTW, the British American Football Assoc. chose to base their rules closely on those of NCAA. I don't know whether they stay with NCAA's changes or started those of a particular year and gone their own way from there.
Robert