Accuracy of dead reckoned positions

Weems  pages 172 & 173 gives the accuracy of dead reckoning as 5% of the distance traveled from last fix.

TM 1-205 (1940) Page 134  gives the accuracy as 1 degree course error and 1 minute ETA

The following texts give the accuracy of dead reckoning as 10% of the distance traveled from the last fix.

AFM 51-40 (1951)

Page 150

Page 309

AFM 51-40 (1973) Page 16-7

H. O. 216 (1967) recommends that beginning navigators use a value of 20 nautical miles per hour plus 1 % of the distance traveled since the last fix as an estimate of the accuracy of dead reckoning until they develop enough experience to make an accurate judgement for themselves. It states further that 50% of the time the error should be only one-third of that amount.

H. O. 216 (1967) Page 184

H. O. 216 (1967) Page 185