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Published by Samuel Penn.

Also, see my profile for things that interest me.

Glendale Website - My main web site.

Yags - Main site for yet another game system, a generic GPL'd tabletop RPG.

Yagsbook - Documentation on the Yagsbook RPG documentation format, a Sourceforge project.

Mapcraft - Documentation on world mapping tools, another Sourceforge project.

Midnight Saga - An Ars Magica campaign.

Active Topics

The current topics are currently under active development (relatively speaking).

Yags is Another Game System - Game design notes for Yags, a Free roleplaying game system I use as the core system for most of my campaigns.

Yagsbook - Notes on an XML based documentation system I use for documenting Yags and related campaigns.

Full Thrust - Notes on Full Thrust

Stargrunt - Notes on Stargrunt.


Ship Design

There is not a rigid ship design system (yet), however the following guidelines are being used in order to try and achieve some consistency in the various designs.

Ship Size

The volume of the ship is measured in displacement tonnes (t). 1t is about 14m^3 (14.12 at 20K). All ship components have a tonnage rating, which is how much space they take up.

A ship also has a limited surface availability. This is assumed to be the square of the cuberoot of the ship's volume. Modifiers may apply at a later date according to shape. This is assumed to be just a unitless number (it's probably in the order of 6m^2 for a cube shaped ship).

The surface availability limits how many weapons can be fitted to the outside of the ship.

Ship Mass

The mass of the ship, by default, is equal to the volume. A stronger hull will increase this by the same multiple that Soak is increased by, e.g.:

Hull Strength Weak Average Reinforced Strong Very Strong Super Strong
Mass Multiplier 0.5 1.0 1.5 2.0 3.0 4.0
Health 2 3 4 5 6 7

Any armour that the ship has is added to that. Decide on how many tonnes of armour to add, and add this to the ship's mass.

To work out the soak value this armour gives, it is log(Mass / Surface available) * TL modifier. See the chart below for the TL modifier.

TL 1-5 6 7 8 9 10 11 12
Soak x10 x15 x20 x25 x30 x40 x50 x60

Manoeuvre Drive

Determine the size of the drive in displacement tonnes. Multiply this by the thrust provided by the given tech level.

TL 8 9 10 11 12
Thrust 10 20 30 40 50

An Advanced drive provides a 25% bonus to thrust. Experimental drives have a 50% bonus. Even advanced drives are rare, only available on a few standard ships. Experimental drives will be one-off (or heavily modified) designs.

The acceleration is equal to total thrust / total mass, in 'g'.

Delta V

Drives need fuel (to power them, reactionless drives are power hungry). 1t of fuel provides a 1t drive with enough power for 1000 turns of maximum thrust. Advanced drives are assumed to use this more efficiently. To find the delta v of the ship, this is “acceleration * (fuel tonnage / drive tonnage)”.

Jump Drive

Used for FTL. A ship must be at least 100t in size in order to effectively mount a jump drive. Jump drives are rated from J1 to J6, and they take up a percentage volume of the ship depending on tech level and capability.

Jump Rating J1 J2 J3 J4 J5 J6
TL 10 35%
TL 11 20%
TL 12 15% 20%
TL 13 10% 15% 20%
TL 14 5% 10% 15% 25%
TL 15 5% 5% 10% 20% 30%
TL 16 3% 5% 5% 15% 25% 40%
TL 17 3% 3% 5% 10% 20% 30%
TL 18 2% 3% 3% 5% 15% 25%
TL 19 2% 2% 3% 5% 10% 20%
TL 20 2% 2% 2% 3% 5% 15%

This volume does not include the fuel required.

yags/starships/design.txt · Last modified: 2015/02/04 22:40 (external edit)