Book 2 small craft design system, by Steve Osmanski
This system is intended to allow players to produce small craft (non-starships under 100 dtons in size) compatible with the CLASSIC TRAVELLER system. It will produce craft close to but not identical with the small craft provided with Book 2. All "tons" mentioned are Traveller displacement tons of volume, all costs are in MCr.
HULL
Designers must specify a hull size, in whole displacement tons (dtons). The smallest practical hull size is 4 dtons, the largest is 99 dtons. All small craft hulls are made of metal alloys. Small craft hulls are usually streamlined.
HULLS</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Name Cost/dton
Hull 0.1
Streamlining 0.01</pre>[/QUOTE]CONTROL
Designers must specify either a bridge, or a pilot's seat and a computer. Small craft must have one or the other for control. Small craft may have a bridge and a computer if desired to assist with weaponry. Pilot's seats and computers may be used on craft up to 25 dtons. Small bridges may be used on craft up to 49 dtons in size, large bridges may be used on craft up to 99 dtons. A pilot's seat includes one small craft couch and the avionics necessary to fly the craft. Small bridges include two small craft couchs, a small airlock, a small fresher, and the avionics and access spaces needed to fly and maintain the craft. Large bridges include two small craft couchs, a small and a large airlock, a large fresher, and the avionics and access spaces needed to fly and maintain the craft.
A pilot's seat gives only 24 hours of life support for one person. Small bridges provide 1 week (7 days) of life support for 10 persons. Large bridges provide 1 week (7 days) of life support for 20 persons.
Computers from Book 2 or HIGH GUARD may be added, use the stats from the HIGH GUARD rules to determine size, cost, and energy points required. Small craft may use "/bis" and "/fib" computer models if desired.
CONTROLS</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Size Cost per
Name (dtons) dton of craft
Pilot seat 0.5 0.025 Includes one small craft couch
Small bridge 4.0 0.025 Includes 2 small craft couchs, small airlock, small fresher.
Large bridge 10.0 0.025 Includes 2 small craft couchs, large and small airlock, large fresher.</pre>[/QUOTE]Designer's Note: This is a major change from Book 2 and HG. I did it since using straight HG rules for small craft bridges resulted in breaking the designs of the Book 2 Slow Pinnace and the Book 2 Shuttle. I also decided to allow the use of the advanced computer models (/bis and /fib) because I just couldn't see any reason why not. After all, Book 2 allowed small craft to use /bis models.
DRIVES
Designers must specify a drive system (which includes a powerplant and a maneuver drive) for the small craft. Each drive system is rated for size (in dtons), cost (in MCr), dtons of thrust produced, energy points produced, and fuel volume required for 1 week (7 days) operation at full thrust. A small craft may only have one drive system. Sufficient fuel for 1 week's operation must be included in the design, but designers may add more fuel tankage for increased endurance. There is a minimum size of 1 dton for any fuel tank, no matter the fuel requirement of the drive system, and so some small craft will have more than 1 week's endurance even with just 1 dton of fuel. Additional fuel tankage above 1 dton may be added in fractions of a dton if the designer desires.
To determine the acceleration of the small craft, divide the dtons of thrust produced by the drive system by the size (in dtons) of the small craft, rounding any fractions down. There is a maximum acceleration of 6Gs, if a drive system should produce more thrust than is needed to give a small craft 6Gs of acceleration, the drive system is considered to be automatically "downrated" to produce just enough thrust to push the small craft at 6Gs (find this "downrated" value by multiplying the craft size (in dtons) by 6). The fuel requirement for a "downrated" drive is reduced by the same proportion as the drive is downrated (as an example, if a drive producing 200 dtons of thrust is downrated to 180 tons of thrust, the fuel requirement for that drive is reduced from 2 dtons per week to 1.8 dtons per week).
The energy points (EPs) produced by the small craft drive system are "excess" energy points, they are not needed to propel the small craft and may be used to power any additional systems the designer requires. Use the EP costs from the HIGH GUARD rules to determine what can be powered. It is possible to add more powerplant to increase EPs available, see the table below. As much additional powerplant may be added as desired but sufficient fuel must be allocated to power it for the entire endurance of the small craft's drive.
SMALL CRAFT DRIVE SYSTEMS</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Size Thrust Cost Fuel needed
Name (dtons) (dtons) (MCr) EPs (dtons/week)
Pod 1 15 4 0 0.15
Launch 2 30 6 0 0.3
Fighter 3 60 8 1 0.6
1/2A 4 100 10 1 1
A 5 200 12 2 2
Shuttle 8 300 20 3 3
B 10 400 24 4 4
Heavy 13 500 30 5 5
C 15 600 36 6 6
Power
Plant 3 0 6 1 1</pre>[/QUOTE]Designer's Note: Here's another big change, although it's more of a deconstruction of the known small craft drives and an extension of them. The "1/2A" drive is from Ken Pick's excellent analysis and extension of Book 2 small craft. Note that the "A", "B", and "C" drives are right out of the Book 2 drive table.
The fuel consumption is a major change. If you use the standard Book 2 rules, small craft drives are five times more fuel efficient than standard starship drives, even when they are using the same drive system. I've always been uncomfortable with the long endurance of TRAVELLER small craft and so I decided that since the small craft were unbelieveably fuel efficient, I'd cut that to a more managable level and reduce the endurance to something I could accept. If you don't like it, just allow the fuel from the table to last 4 weeks instead of 1; that would match up exactly with Book 2 fuel usage.
I added in the 1 EP powerplant for those people who just have to overgun or overcomputer their small craft, effectively it's the same size as a TL 9-12 powerplant from HIGH GUARD.
By the way, I would love it if someone could come up with better designations for the added drive systems, something that would better fit with the Book 2 drive table. The Shuttle drive might be called a "1/2C" drive and the Heavy drive a "1/2E" drive (thus keeping with Ken Pick's designation of the "1/2A" drive as having 1/2 the thrust of the "A" drive), but I couldn't think of what to call the smaller drive systems.
And if starship designers want to use the larger small craft drives to push their starships, go right ahead.
ADDITIONAL COMPONENTS
Designers may add other components from Book 2 or HIGH GUARD to their small craft designs. Unlike the Book 2 system, designers must explicitly pay for whatever additional components are added, there is no "customization" possible without paying for it.
Weapons - Hardpoints must be added if the craft is to mount weapons. A craft with a hardpoint may mount up to three weapons. Turrets are not needed to mount weapons, but if no turret is mounted all weapons mounted can only fire in one direction (forward or aft, side-mounted weapons are not allowed), although the weapons do not all have to fire in the same direction, so a small craft could have a laser pointed forward and a missile rack and sandcaster pointed aft for example. A single person (pilot or gunner) can only fire one kind of weapon pointed in one direction in one combat turn. Sandcasters are not included in this rule, a pilot or gunner can fire a sandcaster (pointed forward or aft) while also firing some other kind of weapon pointed in the other direction.
I offer the following additional components, especially for small craft.
Airlock - Small craft do not have to have an airlock. If they do not, crew and passengers can only enter or leave the small craft if there is atmosphere on the other side of the small craft hatch: from a planet or an enclosed and pressurized small craft bay or a hatch leading directly into the other vessel, unless the crew and passengers are wearing vacc suits.
Small airlocks take up 0.5 dtons and cost MCr 0.025. Most small craft have only one small airlock which is used for passengers and crew. A small airlock has a hatch size of 1 meter by 2 meters, usually oriented vertically for humans, although Hiver airlocks are often oriented horizontally. On a deckplan a small airlock takes up one 1.5 meter square.
Large airlocks take up 1.5 dtons and cost MCr 0.1. Large airlocks are normally used for cargo, although K'Kree use them for personnel airlocks. They have a hatch size of 4 meters by 2.5 meters. They can be oriented vertically or horizontally, depending on the need of the designer. On a deckplan a large airlock takes up three 1.5 meter squares, side by side in a line.
Freshers - Small craft do not have to have a fresher. The crew and passengers of small craft without a fresher are limited to 12 hours of endurance (no matter how much fuel and extra life support is included in the design of the small craft) unless the crew and passengers wear vacc suits in which case their endurance is extended to 24 hours. Having a fresher aboard allows the crew and passengers to use the full life support endurance available in the small craft.
Small freshers take up 0.5 dtons and cost MCr 0.025. They provide facilities for one person at a time.
Large freshers take up 1.0 dtons and cost MCr 0.05. They provide facilities for two people at one time.
Life Support - Small craft without bridges have very limited life support but are usually intended for short duration operations anyway. Small craft with bridges have more life support, sufficient for large groups for a short operation or smaller groups for extended periods. If more life support is desired, a designer may allocate additional life support tonnage to a small craft.
Additional life support takes up 0.5 dtons and costs MCr 0.025. Each unit of additional life support adds 1 week (7 days) of life support for 5 persons. As many additional units as desired may be purchased.
Recharging life support for a small craft costs MCr 0.001 (Cr 1000) per person supported per week. Life support must only be recharged if it is used, and may be partially recharged to save money.
Small craft couchs (like those used for pilots and passengers) provide 24 hours of life support for one person at no additional cost in tonnage or credits. Small craft staterooms provide 1 week (7 days) of life support for one person at no additional cost in tonnage or credits. Regular staterooms provide 1 week (7 days) of life support for 2 people at no additional cost in tonnage or credits.
ADDITIONAL COMPONENTS</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Size Cost
Name (dtons) (MCr) Notes
Hardpoint 0 0.1 Up to three weapons; if no turret weapons are fixed
Small airlock 0.5 0.025 1.5 meter square
Large airlock 1.5 0.1 Three 1.5 meter squares
Small fresher 0.5 0.025 One occupant
Large fresher 1.0 0.05 Two occupants
Life support 0.5 0.025 One week (7 days) for 5 persons
Small craft 0.5 0.025 Life support for one person for 24 hours
couch
Small craft
stateroom 2.0 0.1 Life support for one person for one week (7 days)
Regular
stateroom 4.0 0.5 Life support for 2 persons for one week (7 days)
Emergency
low berth 1.0 0.1 One conscious person for 24 hours, or 4 people in suspended animation.</pre>[/QUOTE]Designers' Note: The weapons rule is somewhat changed to make one-person fighters more interesting. Now they can have mixed weapons but a single pilot can't use them all in one combat turn. The additional components were deduced from the deckplans in Supplement #7 and are provided to allow designers a little more freedom to build unique small craft.
I dispensed with the Book 2 "customization" rule because I just couldn't figure out how to allocate the right amount of money. As far as I could tell there was no set amount the original small craft designs had to spend on "customization" and so I decided the simplest thing to do was to drop the whole idea.
And the rule about freshers was added because I just couldn't imagine spending more than 12 hours confined in a small space without some way to go to the bathroom.
EXAMPLE SMALL CRAFT</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Size Bridge Fuel Drive Weapons ComputerExcess Cost(MCr)
Fighter 10 0.5 1 3 1 1 3.5 11.225
Launch 20 4 1 2 0 0 13 8.8
Ship's Boat 30 4 1.8 5 0 0 19.2 16.15
Slow Boat 30 4 1 4 0 0 21 14.15
Pinnace 40 4 2 5 0 0 29 17.5
Slow Pinnace 40 4 1 4 0 0 31 15.5
Cutter 50 10 2 5 0 0 33 18.85
Shuttle 95 10 2.85 8 0 0 74.15 32.925</pre>[/QUOTE]Here are the Book 2 small craft, built in this design system. As far as tonnage goes, the Launch, Cutter and Shuttle are just about right, having nearly the same (or exactly the same) excess tonnage as the Book 2 designs. The Fighter, Ships Boat, and Pinnace gain quite a bit of excess tonnage, the Slow Boat and Slow Pinnace lose some. Costs vary quite a bit, although the Ships Boat, Slow Boat, and Shuttle are just about the same.
Here are some additional small craft designed by myself to test this design system.
ADDITIONAL SMALL CRAFT</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Name Size Bridge Fuel Drive Weapons ComputerExcess Cost Notes
Jolly Boat 20 4 1 3 0 0 12 7.45 3 Gs
Work Pod 5 1 1 1 0 1 1 6.775 3 Gs, two crew, Mod/1
Lifepod 10 .5 1.5 1 0 1 0 8 1 G, one crew, Mod/1</pre>[/QUOTE]Jolly Boat: Using a 20-dton hull, the jolly boat is capable of 3-Gs acceleration, carries one ton of fuel (giving 1.67 weeks endurance for the power plant) and has a small bridge allowing a crew of two and providing life support for 10 people for one week. A jolly boat may mount missile racks and sandcasters, it may not mount lasers. The maximum computer for the jolly boat is the Mod/2bis. The jolly boat has twelve tons excess space available and costs MCr 10.8.
Work Pod: Using a 5-dton hull the work pod is capable of 3-Gs acceleration, carries one ton of fuel (giving 6.67 weeks endurance for the power plant) and has a crew of two (in small craft couches) with life support for two people for 24 hours. The work pod does not have an airlock; crew and passengers must embark from/disembark into a pressurized area. A work pod may mount missile racks or sandcasters, it may not mount lasers. Usually the work pod's hardpoint is used to mount various work arms and remote-operated tools. The work pod comes with a Computer Mod/1 and may have up to a Mod/2bis computer. The work pod has one ton excess space available and costs MCr 6.775.
Lifepod: Using a 10-dton hull the lifepod is capable of 1-G acceleration, carries 1.5 tons of fuel (giving 10 weeks endurance for the power plant) and has a crew of one (in a small craft couch). Six emergency low berths are installed, acting as seats for up to 6 passengers in regular service with life support for all crew and passengers for 24 hours, or acting as low berths for up to 24 passengers for as long as the power plant endurance. The lifepod has no airlock; crew and passengers must embark from/disembark into a pressurized area. The lifepod has no hardpoint and may not mount any weapons. It has a computer Mod/1 to control the craft while the crew and passengers are in suspended animation; the craft may not mount any other computer. The lifepod has no excess space and costs MCr 7.95.