All ranges are measured 1:1 in inches
This is actually a good estimate of the Leviathans map. In essence, the normal hexagonal shaped range profile is turned into a circle averaging the same area. The tips of the hexagon are cut short and the sides are bumped out slightly. This keeps ranges the same as on a hex map on average.
The Torpedo Launch and Resolution phases proceed as described in the Commander’s Manual and in exactly the same way. The only difference is the ranging placement of the Torpedo Target Token.
The Torpedo Launch Token is placed under the firing location hex as normal. It will remain in this location as ships move around until the Torpedo Resolution phase.
The matching Target Token is placed a full 18 inches out and in arc. If the full 18 inches is not possible it is placed out as far as can be.
The line of sight string is used to draw a direct line from Launch Token to the matching Target Token as normal.
This shot results in a Port Location roll of 3DRed against the 3 Hex ship.
Range for guns is found by placing a ruler in contact with the base of the firing ship and measuring to the target ship.
For example, the Offensive Screening Token below is placed at the 8 inch mark for a Bow gun with a long range of 8.
The short range of 4 is shown by the Defensive Screening Token placed at the 4 inch mark.
There are guns with ranges longer than 12, like the Bow guns on most 4 Hex ships.
In this instance the HMS Leviathan is ranging its Bow guns with 16 long and 8 short. This translates to 16 inches long range and 8 inches short range. To measure this, first place a marking Token the full 12 inches of the ruler. Then advance to ruler 4 inches [12+4=16], the marker Token will now be at the 8 inch mark [12-4+8]. Move the Marker Token the remaining 4 inches to the end of the ruler, this is the full long range of 16 inches. Without moving the ruler a marker can be placed at the 4 inch mark to find the short range of 8 [4+4+8].
It is not necessary to mark each of these lengths every time a gun is fired. The above example shows all ranges for completeness only. In reality you only need to know if a target is in range and which dice, short or long, will be used.