User Tools

Site Tools



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.


Spaceship Combat

Combat is assumed to use 1” = 1km, and 1 turn = 10 seconds.

Attack roll

To hit, roll skill (Perception or Dexterity x Spaceship gunnery), plus attack bonus of the weapon.

The base difficulty is 15, +5 per increment, -3 per point of size of target over the size of the weapon.

Size Weapon type
10 Fixed mount, small turret (1t).
10 Light missile (1t).
15 Large turret (3t).
15 Heavy missile (5t).
25 Bay emplacement (50t) .
30 Large bay emplacement (100t).
30+ Spinal mount weapons.

If the weapon is larger than the target being aimed at, then the -3 applies the other way (+3 to the difficulty per point the target is smaller than the weapon's size).

If the weapon is more than 5 size points larger than the target, then halve the attack roll if the target is within point blank range of the weapon. If the target is more than 10 size points larger, then attacks within close are impossible except on a natural 20, and halve attacks at all other ranges.

Point blank range is very close to the target, well within 1”.


The target probably wants to try to evade. Multiple evasions are possible as for multiple defences. A single ship counts as one attacker, regardless of the number of weapons, unless at point blank range. At point blank range, each weapon counts as a separate attacker.

Roll Dexterity x Spaceship piloting or Perception x Spaceship systems to evade, modified by range and size. A full roll is always made, even against lasers, since these weapons need prolonged focusing on the target to cause full damage.

Remember than attribute is capped to the Agility of the ship.

Stealth does not make it harder to hit (even though it modifies Size), since if you can see it, then you're aiming for the centrepoint anyway.

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