There have been no less than a hundred different firefinder alidades invented since the creation of fire lookouts. While the Osborne was the most widely used, it seems that each state, and even individual national forests, came up with their own version; no doubt due to the high cost of the Osborne.

The first Koch Board in 1915 was simply a narrow strip of tin pivoting on a nail driven in the center of the map board; the ends bent upright and notched to serve as front & rear sights. Elers Koch was one of the earliest USFS top level regional foresters in Missoula, Montana. Whether he invented it or not, it got his name.

In 1917 Fred Colburn created an alidade board capable of drawing the panorama in relief on the outer edge of a circular map in New Hampshire. The idea found wide use from Maine to Montana in the next decade.

The 1928 Bosworth Firefinder was invented in northern Idaho by Jim Bosworth (no relation to Dale, the USFS Chief). It was built like an army tank, but also weighed "a ton", so it found little acceptance outside USFS Region-1. The 1930s saw the use of telescopes, transits, and several other innovative contraptions.

With the War years of 1942-1945 came some thrifty non-metal firefinder alidades, as Aircraft Warning Service (AWS) lookouts were established to watch for enemy aircraft along our coastal states. In 1942, the Washington state Division of Forestry came up with one made entirely of wood.

The post-war years saw numerous different versions. Wisconsin designed an 8-sided wood & plastic protractor. Maine, Arkansas, Minnesota, New Jersey, Pennsylvania, Kentucky, Michigan, Texas, Klamath California, Boise Idaho, and a host of other states, nations and individuals came up with their own "better" version. There were even binoculars with azimuth bearings that locked in on the fire.

One might say, almost as good, and certainly the least expensive at 10 cents, is used yet today in Australia... a string hanging from the ceiling, precisely above the center of the room, with pencil marks, 0 to 360, around the windows.

1915 Koch Board