Crucially, that's 63 miles North of Virginia. Latitude is relatively straightforward to measure. It's pretty well given that if you sail west from Northern Euro

Crucially, that's 63 miles North of Virginia. Latitude is relatively straightforward to measure. It's pretty well given that if you sail west from Northern Europe, you'll hit North America. Hitting it at your intended latitude might depend on the winds, but one you bump into it, it should be pretty easy for a competent navigator to tell you how far off your target you were in latitude. Given decent maps, figuring out longitude is probably not a tall order either if you know your latitude and you're on the coast.