Ressupply Ship Question

Alrighty Kaulens, here goes;
Im in my second patrol and I am now using realistic O2, CO2, Batt. and Fuel, I was ordered to patrol AM41 from Wilhelmshaven and ended up chasing 2 merchants and wasting alot of fuel, now I am within range of Belchen and it is supposed to be in the area (by greenland) at this time date.

So first, are the supply ships EXACTLY on the dot where they should be at? or am I going to have to search for her?? (I hope its close to there because once I reach that spot Im only going to have about 300-400km worth of fuel left

Second, I assume docking is the same as a in port??

and third are the number of days spent docked changed or anything??

thanks guys Cant really fudge this up or Im stuck in the atlantic with no fuel