Further supporting notes from Pablo, posted at the Lair:
Regarding the question of U-boat ranges, here are some potentially useful comparisons between the real world and the world as it is modeled in Silent Hunter III:
The surface area of the earth
Real life: ~510 million square kilometers (km^2).
SH3: ~933 million km^2 (180° N-S x 360° E-W x 14400 km^2/deg^2)
Distance per degree of longitude at 5° N/S latitude (Penang/Jakarta)
Real world: ~111 km
SH3: 120 km
Distance per degree of longitude at 45° N/S latitude (La Spezia)
Real world: ~79 km
SH3 World: 120 km
Distance per degree of longitude at 63° N/S latitude (Trondheim)
Real world: ~50 km
SH3 World: 120 km
Distance per degree of longitude at 74° N/S latitude (Svalbard)
Real world: ~31 km
SH3 World: 120 km
Distance per degree of latitude (all latitudes)
Real world: ~111 km
SH3 World: 120 km
The complicating game factors are:
Almost all of the gameplay in SH3/GWX occurs between 74°N latitude (Svalbard) and about 40°S latitude (Cape Town, South Africa; Melbourne, Australia)
U-boat bases can be found from near the equator (Penang) to over 60 degrees N latitude (Trondheim).
Silent Hunter III entails a lot of east-west sailing as well as north-south, so I don't think we should base range changes solely on the effect of changing latitude.
I suggest basing the new range on the extent to which the SH3 world is larger than the real world at the point where the U-boats are operating, as follows:
SH3: the distance from Point "A" to Point "B" is always square root of (120^2 + 120^2), or about ~170km by the Pythagorean Theorem.
Real: distance obtained from "Latitude/Longitude Distance Calculator,"
http://www.nhc.noaa.gov/gccalc.shtml
Case 1: 45°N latitude (La Spezia)
Real life: the distance from Point "A" to Point "B" is ~136 km
The "SH3:Real" ratio is 170:136, or about 1.25:1
Case 2: 54°N latitude (Kiel)
Real life: the distance from Point "A" to Point "B" is ~128 km
The "SH3:Real" ratio is 170:128, or about 1.33:1.
Case 3: 63°N latitude (Trondheim)
Real life: the distance from Point "A" to Point "B" is ~122 km
The "SH3:Real" ratio is 170:122, or about 1.39:1