I have just created a CT Bk2 LASH tug and lighters, with an economic analysis, and I find my numbers to be a little unbelieveable, so I am posting my work here for others to check. Frankly, this ship makes too much money.
Book 2 1000-ton LASH (Lighter Aboard SHip) tug (type TL)
A classic example of the LASH (Lighter Aboard SHip) concept, where a tug carries other non-jump-capable vessels through jump, the type TL uses a custom 1000-ton unstreamlined hull. Mounting jump drive-W, maneuver drive-W, and powerplant-W, the tug is capable of jump-5 and 5-Gs acceleration by itself, jump-2 and 2-G acceleration carrying a single 1000-ton lighter, or jump-1 and 1-G acceleration carrying two, three or four 1000-ton lighters. The tug's onboard fuel tankage of 550 tons supports all these drive/load combinations without any external fuel sources. A Model/5 computer is installed next to the tug's bridge.
As is typical of LASH designs, which are intended to spend most of their time in jump, each of the 10 people in the crew have individual staterooms. This design also allows the lighter crews to live aboard the tug, and there are also individual staterooms provided for them, giving 26 staterooms altogether. An additional 26 displacement tons of space has been given over to additional crew space, including a recreation room, workshops, and a small sauna. The tug has 50 tons of cargo space to be used for ship's supplies, allowing for long-duration operations without resupply. A 30-ton ship's boat is carried to serve as a liberty craft and general support boat.
The type TL costs MCr641, which does not include any lighters.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Type TL specifications: tonnage MCr
Hull (1000 tons, 1000 100
unstreamlined)
Jump Drive W 110 210
M-Drive W 41 84
Powerplant W 64 168
Fuel 550
Bridge 20 5
Mod/5 computer 5 45
26 staterooms 104 13
Ship's boat 30 16
Cargo/supplies 50
Rec space 26
Totals 1000 641</pre>[/QUOTE]Book 2 LASH 1000-ton lighter (Type LH)
Intended to be "self-propelled cargo bays" for the Type TL tug vessel, the type LH lighter is build on a standard 1000-ton streamlined hull. Mounting maneuver drive-E and powerplant-E, the lighter is capable of 1-G acceleration and carries 10 tons of fuel to support the powerplant. A Model/1 computer is mounted next to the bridge. Two staterooms are shared by the crew of four during in-system operations, however staterooms are provided aboard the tug for all lighter crews during jump, to allow for social interaction. The staterooms in the lighters do remain accessible during jump, allowing lighter crews to have some private space if they wish it. The lighter has a 936-ton cargo bay. There are no ship's vehicles.
The type LH costs MCr178.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Type LH specifications: tonnage MCr
Hull (1000 tons, 1000 110
streamlined)
M-Drive E 9 20
Powerplant-E 16 40
Fuel 10
Bridge 20 5
Mod/1 computer 1 2
2 staterooms 8 1
Cargo Bay 936
Totals 1000 178</pre>[/QUOTE]Economics of the LASH concept.
The LASH tug is assumed to charge a fee of Cr500 per ton of vessel carried through one jump and is assumed to jump 35 times a year (three times a month for eleven months, with the last month taken up with two unpaid jumps getting to the shipyard and then having the annual maintenance performed). Refined fuel costs twice as much, since it is assumed to be delivered.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">LASH tug expenses (yearly): Credits
Fuel (35 jumps x 500 tons fuel/jump 18,100,000
+50 tons pp fuel x 12 months
x Cr1000/ton refined fuel)
Life support (26 s/r x 12 months) 1,248,000
Annual maintenance 641,000
Salaries (Cr44,000x12 months) 528,000
Bank payment (MCr2.671 x 12 months) 32,050,000
Total annual cost for the LASH tug: 52,567,000</pre>[/QUOTE]</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">LASH income (yearly): Credits
Carriage fees: (Cr500/ton x 4x1000 ton 66,000,000
lighters/jump x 33 paying jumps/year)
Gross profit: Cr 13,433,000 per year.</pre>[/QUOTE]</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">LASH lighter expenses (yearly): Credits
Fuel (10 tons/month x 12 months) 60000
Life support (2 s/r X 12 months) 96000
Annual maintenance 178000
Salaries (Cr17,000/month x 12) 204000
Bank payment 8,900,000
Carriage fees: (Cr500/ton lighter 16,500,000
x 33 jumps/year)
Total annual expenses for lighter: 25,938,000</pre>[/QUOTE]</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Lighter income (yearly): Credits
Cargo fees: (936 tons x Cr1000/ton 30,888,000
x 33 jumps/year)
Gross profit: Cr 4,950,000 per year.</pre>[/QUOTE]In short, under this system the LASH tug earns MCr 0.5 for every lighter she carries for one jump. The LASH tug can only afford to miss 26 such carriage fees in a year's operation before she starts to lose money, so there must be plenty of lighters and they must make rendevous smartly so the tug can quickly get back into jump.
The lighters also need to make three jumps a month, implying the existence of enough LASH tugs to allow this. Each jump a lighter fails to make costs Cr 436,000 in profit (Cr936,000 in unearned cargo fees, minus the Cr 500,000 in carriage fee not spent). Lighters can afford to miss 12 jumps before they start losing money. If 33 jumps a year can be guaranteed, LASH lighters can even afford to undercut the standard Cr1000/ton freight charge and still make money.
