If my tug has a range of 100 billion km, when it tractors another ship will it still have that range or will fuel use account for the newly added tonnage?
For a tug design with range
R, tugging a ship
N times its own size:
The one-way range is
R/(
N+1). The tug can go that far before running out of fuel.
The round-trip limit is
R/(
N+2). The tug can go that far, release the payload, and still have enough fuel to return.
For example:
My tugs tend to be around 50kt.
My large stations tend to be around 125kt.
125kt/50kt = 2.5.
Therefore:
The one-way range of my tug while towing a large station is the tug's design range divided by 3.5.
The round-trip range of my tug while towing a large station is the tug's design range divided by 4.5.