🔍 Key Concepts

• Set and drift of current – drift is the distance the current moves you from your DR track; set is the direction it moves you • Difference between DR (dead reckoning) position, fix, and EP (estimated position) • How current is actually determined on a plot: comparing the DR position (no current) to the observed position (with current) over a known time interval

💭 Think About

• Look at each choice and ask: does this describe how navigators really measure or use current on a standard plotting sheet? • Which position pair do you use to determine current: DR-to-fix, DR-to-EP, or something else? Why? • If you have found current once, would a prudent navigator ignore it for later plotting, or would they carry it forward (with caution)?

✅ Before You Answer

• For each option, verify whether it uses the correct pair of positions (simultaneous DR and fix vs DR and EP) to determine set and drift • Check your definition: drift = distance of the current’s effect over a known time, not a rate unless divided by time • Ask yourself if a statement that calls current an "unknown variable" matches good navigation practice once you’ve just measured it on the chart