Vehicles and Constructs

For the most part, adventures in Yags will revolve around people and sometimes animals. Objects such as vehicles and buildings exist, but only as part of the backdrop, or as mechanisms to get from one event to another.

Occassionally however, such things become a focal point of the game, and it becomes useful to know a bit more about how vehicles and buildings fit into the world as described by Yags - especially if the are used in combat situations.

These rules cover the description and use of vehicles within the game. Also covered are buildings and other non-living things. The generic term used is Construct. Also covered are the use of large vehicle mounted and infantry support weapons. Most characters will never need to worry about these, even in modern campaigns, but the occassional scenario will call for their use.

Scaling Vehicles

Yags uses a generic Size attribute for all creatures within the game, and this is extended to cover vehicles as well. Since Size is logarithmic, it will rarely get above 20 for ground vehicles, it will generally be below 100 (even objects such as the Death Star or Skylark of Valeron). This does lead to a degree of imprecision at the higher levels, but at that point a large level of abstraction is probably a good thing.

A Size of 10 is considered to be a vehicle of 10m^3, and each +5 Size increases this by a multiple of 10. Size 10 is more than enough for a family car, Size 15 is adequate for a large tank and a WWII battleship would be in the high twenties. Some example sizes are shown in the list below, to give an idea of how sizes increase.

Vehicle	Size
Motorbike.	5
Family car.	10
T-34 Tank.	11
X-Wing (Star Wars).	14
Train carriage.	16
F-16.	17
200t Free Trader (Traveller).	22
Boeing 747.	26
Bismark.	28
USS Enterprise CVN-65.	32
Star Destroyer (Star Wars).	44
Death Star (Star Wars).	80
Skylark of Valeron (EE 'Doc' Smith).	94
Earth.	110

Weapons and armour have a special Vehicle property - Vc - which mark them as being of Vehicle Scale. Standard weapons do considerably less damage to vehicles, and vehicle weapons pretty much ignore the armour and soak of people.

Soak

A construct will normally have a base soak equal to its size. If it is stronger or weaker than usual then this can vary. The following guide can be used to determine the base soak of a vehicle or building. These are guidelines only, and any values inbetween (or outside) those given can be used.

Soak	Type of construct
x0.5	Weak. A very weak object, normally poorly constructed or delibrately designed to be light.
x1	Average. Any typical building or vehicle will have a base soak equal to its size.
x1.5	Reinforced. If the object has been reinforced, such as a rally car, SUV or heavily constructed building. About the strongest most flying vehicles will be.
x2	Strong. Object has been designed from the start to be tough and durable. A tank, battleship or bunker will tend to be this strong.
x3	Very strong. A heavily built vehicle, such as the strongest tanks, or a heavily toughened bunker. The entire design of the construct is geared towards making it strong, rather than pretty or fast.
x4	Super strong. A heavily built vehicle made from ultra-tech materials (TL10+), or one which is designed to do little more than resist damage at the expense of being very space inefficient.
x5	Ultra strong. Ultra-tech object which does little more than resist damage which is also very space inefficient, but also highly resistant to damage.

This is the base soak of the construct, and is not affected by heavy weapons or other effects.

As for characters, vehicles and buildings may be armoured. Many heavily armoured vehicles will have two armour ratings - one for the heavy front armour, and the second for the lighter sides and rear. Most armour on vehicles is considered to be Light vehicle. Heavy vehicle weapons (normally armour piercing weapons, such as HEAT) halve such armour.

Armour	Examples of armour
5-30	Armoured vehicle. Armoured vehicles (such as APCs, armoured limo) will tend to have armour in the 5-20 range.
20-30	Light tank. Heavily armoured vehicles, such as tanks, will tend to have up to 30 points of front armour.
30-50	Heavy tank. The toughest of tanks will have armours in this sort of range.
40-60	Battleships. Heavy battleships.
-10	Tech -6. At tech levels prior to 7, materials are limited so reduce armour values by 10.
-5	Tech 7. For tech level 7 era vehicles, reduce armour levels by 5.
+5	Tech 9-10. At tech levels 9-10, increase armour by +5.
+10	Tech 11+ At tech levels above 10, increase armour by +10.

Damage

Vehicles have a single damage track, with a number of states: Okay, Superficial, Medium, Critical and Destroyed. The latter is equivalent to Fatal wounds for characters, and results in the vehicle being rendered completely inoperable.

All damage is applied to this track, and is of two types - Major and Minor. All vehicle scale weapons cause Major damage to vehicles. Such damage is equivalent to wounds against characters, and is additive.

Character scale weapons may cause Minor damage to vehicles. This is treated like stuns, in that it is non-cumulative. If the damage caused is less than half the current damage, then the attack is ignored. If it is more than half, but not more than the current damage, then one level of damage is caused. If the damage is greater than the current damage, then the total damage is equal to the damage caused.

Major damage may cause critical hits against the vehicle. Minor damage is normally superficial.

The damage levels for a vehicle are split equally between Superficial, Medium and Critical, with extra levels going to the lower bands first. A size 10 car would have 4 levels of Superficial, 3 of Medium and 3 of Critical.

Hitting Vehicles

Most vehicles tend to be much larger than normal human targets, and so are easier to hit. Vehicles suffer the normal penalty to their 'to be hit' number, of -3 per point of size about 5. A size 20 vehicle for instance will have a 'to be hit' number of -30. This makes vehicles very easy to hit at long range.

Vehicle weapons are also affected by this, and suffer a penalty to their attack bonus based on their size - larger weapons are harder to aim, and generally no good for shooting at people. A vehicle which is 'size 10' for example will have a penalty of -15 to its attack bonus, which may give it a negative attack bonus. This will be factored into the weapon's statistics.

Vehicle Attributes

All vehicles have the following attributes.

Acceleration

How quickly the vehicle accelerates, in metres per round per round.

Critical

The threshold at which the vehicle suffers criticals. It is equal to the number of damage levels the vehicle has in its Superficial level.

Move

How fast the vehicle can move, in metres/round. This is normally the top speed of the vehicle in metres per round. This is about 2.2 times (or twice) the miles per hour speed.

Size

The general size of the vehicle, normally based on the volume. Volume is used instead of Mass (which animal Size is based on) because this is normally easier to obtain for real world vehicles.

Soak

How good the vehicle is at resisting damage. This normally defaults to the Size of the vehicle.

Using Vehicles

Generally, driving or piloting a vehicle will use dexterity x Drive or a dexterity x Pilot skill check, depending on the type of vehicle. In either case, your Dexterity is capped to the Agility of the vehicle, meaning big and slow vehicles generally don't require fast reactions, just skill, and even that doesn't make much difference.

Very large vehicles, such as battleships for example, won't have a 'pilot' as such, and tend to be controlled by a number of people down in engineering, or a group of computer operators. In this case, controlling the vehicle uses an operation skill, such as Ship operation or Spaceship operation.

When making a manouevre, a pilot or drive check is often required, and the difficulty depends on the speed that the manouevre is performed at.

Speed of manouevre	Target
Careful. A slow and safe speed.	-10
Moderate. A safe speed.	+0
Quickly. A bit faster than is advised.	+10
Fast. Somewhat fast.	+20
Very fast. Dangerously fast.	+30

You're generally better off slowing down before making a tricky manouevre, however you can try to force a persuer to crash or lose you by taking a bend at high speed.

Spaceships

Spacecraft movement is given as an acceleration and a delta-vee. The acceleration is in metres per second per second, and the delta-vee is the maximum velocity the ship can attain in km/s if it were to accelerate for as long as possible.

Example Vehicles

Listed below are some sample vehicles, showing a range of sizes and capabilities from the modern day and recent history.

Modern

Family Car

5 door hatch back.

TL: 8; Mass: 750kg ; Cost: 15000 Cr

Speed: 180 km/h; Accl: 10 km/h/s; Range: 600 km

Land Rover

Sports Utility Vehicle

TL: 8; Mass: 3t ; Cost: 25000 Cr

Speed: 220 km/h; Accl: 15 km/h/s; Range: 500 km

Motorbike

Typical average motorbike.

TL: 8; Mass: 250kg ; Cost: 5000 Cr

Speed: 160 km/h; Accl: 20 km/h/s; Range: 360 km

An typical good performance motorcycle from the late 20th century.

SUV

Sports Utility Vehicle

TL: 8; Mass: 1.25t ; Cost: 35000 Cr

Speed: 220 km/h; Accl: 15 km/h/s; Range: 500 km

WWII Tanks

M-3 Halftrack APC

Light infantry transport.

TL: 6; Mass: 10.2t ; Cost: 2600 Cr

Manufacturer: US; In-Service: 1942

Speed: 64 km/h; Accl: 3 km/h/s; Range: 450 km

A half-tracked armoured personel carrier with an open top.

Panzer IV

German medium tank.

TL: 6; Mass: 27.5t ; Cost: 26000 Cr

Manufacturer: Germany; In-Service: 1939

Speed: 46 km/h; Accl: 3 km/h/s; Range: 280 km

German tank common at the start of the war, over ten thousand were constructed, with varying models being based on the standard design.

Panzer VI - Tiger

WWII German heavy tank.

TL: 6; Mass: 62.6t ; Cost: 56000 Cr

Manufacturer: Germany; In-Service: 1942

Speed: 46 km/h; Accl: 3 km/h/s; Range: 140 km

The best of the German tanks.

Sherman M4

Medium tank.

TL: 6; Mass: 33.2t ; Cost: 31000 Cr

Manufacturer: US; In-Service: 1941

Speed: 45 km/h; Accl: 3 km/h/s; Range: 330 km

The standard US tank, which was used throughout the war by the US and her allies.

T-34

WWII Russian heavy tank.

TL: 6; Mass: 28.6t ; Cost: 65000 Cr

Manufacturer: Russia; In-Service: 1940

Speed: 58 km/h; Accl: 3 km/h/s; Range: 180 km

Russian heavy tank.

WWII Ships

Bismark

German Battleship

TL: 6; Mass: ; Cost: Cr

Water Speed: 30 km/h; W Accl: 1 km/h/s; W Range: 17200 km

Vehicle Weapons and Armour

Weapons which have a property of Vehicle (Vc) completely ignore the Soak of standard targets unless they are in Heavy armour. This means that the total soak roll is always zero for these targets. Standard targets with heavy armour have their total soak roll halved.

Heavy vehicle weapons always ignore the soak of character scale targets, regardless of the armour they are wearing.

Any target which has Vehicle armour halves the damage from standard weapons, and all damage done is Minor.

Big Guns

From the point of view of large vehicles, pretty much any weapon that is considered man-portable is tiny. This includes heavy machine guns and similar weapons which may be vehicle mounted but which are used and pointed by people. Tiny weapons are considered to be Size 5, and do less damage against anything of Size 15 or more. Effectively, Major damage becomes Minor damage, and Minor damage is ignored.

A Tiny weapon cannot effectively harm any vehicle (or creature) of Size 20 or greater. However, they may be able to harm individual turrets or other surface points.

Dedicated anti-armour weapons, such as the main gun of a tank, are considered to be Small. For Size purposes they have a Size of 10.

Naval guns and artillery weapons are considered to be Medium weapons, and have a Size of 20.

The size of the gun affects the size of target it is designed to hit. The base difficulty to hit a target is 15, modified by +5 per point of Size the target is smaller than the weapon. A medium naval gun base a base difficulty of 90 (15 + 75) to hit a person. Of course, a near miss is probably going to be good enough.

Starship Combat

If a battle is being fought between large vehicles, such as battleships or spaceships, it is suggested that a turn of 5 minutes is used instead of the usual 5 second rounds. Most weapons which are of use at this scale will tend to have very slow rates of fire, comparable to 1 per 5 minute turn.

How well a spacecraft moves is measured by its acceleration, which is given in 'g'. Every 'g' of acceleration allows the ship to accelerate up to (roughly) 1000km/turn/turn. For this reason, all ranges are measured in multiples of 1000km.