GT Fixed Mount Weapons

Kenneth Witt:

Using Bay Weapons as Spinal Guns

The GURPS Traveller Starship design rules suggest that warships too small to use a conventional spinal mount weapon may use a bay weapon in a fixed mount as a scaled down spinal weapon. There is only one major difference between a bay mount and a fixed spinal weapon and that is, of course, the mount. A bay weapon always has either a full rotation universal (external) or a limited rotation casemate (internal) mounting to allow the weapon to rotate or elevate to track targets independent of the attitude of the ship. The mount (either universal or casemate) masses half as much as the base weapon and displaces one cubic foot per 50 lbs. A spinal weapon has no mounting of any type. It is welded to the frame of the starship and forms the ship's major fore to aft structural element. The only way to track a target with a spinal mount weapon is to point the nose of the ship at the target. So, to convert a bay weapon for use as a spinal mount, you need only subtract off the mass, volume, and cost the 'Mount'. That is where the table below comes in. It shows revised values for the standard bay mount energy weapons redesigned as spinal mount weapon systems. These small spinal mount guns are suitable for use on warships with displacements of around 1,000 to 2,000 dTons. Note that all these weapon systems include a dedicated hardened mainframe computer of complexity: Tech Level minus three. The dedicated fire control computer provides a targeting bonus of Tech Level minus two for the weapon.

Weapon Description TL Compact Volume Mass Cost Power (MW)
Sm Particle Beam/ 9 7.4 GJ 9 No 44 293.5 68.04 246.7
Sm Particle Beam/10 12.8 GJ 10 No 34 336.8 23.13 427.0
Sm Particle Beam/11 23.3 GJ 11 Yes 41 345.5 57.50 776.7
Lg Particle Beam/ 9 14.9 GJ 9 No 88 590.8 136.88 496.7
Lg Particle Beam/10 28.5 GJ 10 No 76 749.2 51.40 950.0
Lg Particle Beam/11 46.7 GJ 11 Yes 81 692.4 115.18 1556.7
Sm Meson Beam/12 12.8 GJ 12 No 34 336.6 20.95 427.0
Sm Meson Beam/13 23.3 GJ 13 Yes 41 345.2 56.67 776.7
Lg Meson Beam/12 23.3 GJ 12 No 76 748.6 46.54 950.0
Lg Meson Beam/13 46.7 GJ 13 Yes 81 691.9 113.51 1556.7

 

Weapon Description TL ROF Damage Half Range Max. Range Acc
Sm Particle Beam/ 9 7.4 GJ 9 1/60 4d x 1,000 10,201 / 1 30,603 / 3 32
Sm Particle Beam/10 12.8 GJ 10 1/60 6d * 1,000 14,642 / 1 43,925 / 4 33
Sm Particle Beam/11 23.3 GJ 11 1/60 8d * 1,000 21,392 / 2 64,177 / 6 34
Lg Particle Beam/ 9 14.9 GJ 9 1/60 5d * 1,000 14,475 / 1 43,426 / 4 33
Lg Particle Beam/10 28.5 GJ 10 1/60 8d * 1,000 21,839 / 2 65,518 / 7 34
Lg Particle Beam/11 46.7 GJ 11 1/60 5d * 2,100 30,286 / 3 90,858 / 9 35
Sm Meson Beam/12 12.8 GJ 12 1/60 6d * 1,000 14,642 / 1 43,925 / 4 33
Sm Meson Beam/13 23.3 GJ 13 1/60 8d * 1,000 21,392 / 2 64,177 / 6 34
Lg Meson Beam/12 23.3 GJ 12 1/60 8d * 1,000 21,839 / 2 65,518 / 7 34
Lg Meson Beam/13 46.7 GJ 13 1/60 5d * 2,100 30,286 / 3 90,858 / 9 35

Fixed Weapons on Fighters and other Small Craft

Small craft, such as fighters can also make use of fixed weaponry, but the volume of the much smaller weapons (typically lasers) used by fighters will change by only a fraction of a displacement ton when the mount is removed. However customized fixed lasers with no mounts can be designed for this application. By holding the volume constant and using the space that is occupied by the mount in a conventional design, each type of fixed mount laser may be made marginally more powerful than a weapon designed for a turret. Each laser on the following table includes the base weapon with full stabilization, the required fusion power slice plus long term access space, and a rechargeable power cell. Unlike the larger spinal mounts above, no provision for a dedicated computer or gunner is included in the design. When a fighter is built around one of the weapons in the table below, the gun must be operated by a pilot or gunner manning a crew station on the bridge (cockpit) of the fighter and the Targeting program needs to be run on the ships computer.

Weapon Description TL Compact Volume Mass Cost Power (MW)
Fixed X-Ray Laser/10 360 MJ 10 No 1 8.95 1.20 16.0
Fixed X-Ray Laser/10 1,000 MJ 10 No 3 24.86 2.70 44.3
Fixed X-Ray Laser/10 1,800 MJ 10 No 5 44.74 4.86 79.8
Fixed X-Ray Laser/11 490 MJ 11 Yes 1 7.19 1.44 21.7
Fixed X-Ray Laser/11 1,600 MJ 11 Yes 3 23.17 4.58 70.0
Fixed X-Ray Laser/11 2,600 MJ 11 Yes 5 38.13 7.52 115.3
Fixed X-Ray Laser/12 510 MJ 12 Yes 1 7.48 .85 22.6
Fixed X-Ray Laser/12 1,500 MJ 12 Yes 3 21.99 2.49 66.5
Fixed X-Ray Laser/12 2,600 MJ 12 Yes 5 38.11 4.30 115.3
Fixed X-Ray Laser/13 505 MJ 13 Yes 1 7.40 .85 22.4
Fixed X-Ray Laser/13 1,600 MJ 13 Yes 3 23.00 2.6 69.6
Fixed X-Ray Laser/13 2,600 MJ 13 Yes 5 38.10 4.30 115.3

 

Weapon Description TL ROF Damage Half Range Max. Range Acc
Fixed X-Ray Laser/10 360 MJ 10 1/60 5dx60(2) 20,455 / 2 61,364 / 6 32
Fixed X-Ray Laser/10 1,000 MJ 10 1/60 5dx100(2) 34,091 / 3 102,273 / 10 33
Fixed X-Ray Laser/10 1,800 MJ 10 1/60 6dx100(2) 45,738 / 5 137,213 / 14 34
Fixed X-Ray Laser/11 490 MJ 11 1/60 5dx90(2) 26,250 / 3 78,750 / 8 33
Fixed X-Ray Laser/11 1,600 MJ 11 1/60 5dx150(2) 47,137 / 5 141,410 / 14 34
Fixed X-Ray Laser/11 2,600 MJ 11 1/60 4dx220(2) 60,467 / 6 181,401 / 18 35
Fixed X-Ray Laser/12 510 MJ 12 1/60 4dx140(2) 29,215 / 3 87,645 / 9 33
Fixed X-Ray Laser/12 1,500 MJ 12 1/60 6dx150(2) 50,103 / 5 150,310 / 15 34
Fixed X-Ray Laser/12 2,600 MJ 12 1/60 6dx180(2) 65,964 / 7 197,892 / 20 35
Fixed X-Ray Laser/13 505 MJ 13 1/60 6dx110(2) 31,494 / 3 94,482 / 9 33
Fixed X-Ray Laser/13 1,600 MJ 13 1/60 6dx180(2) 55,531 / 6 166,592 / 17 34
Fixed X-Ray Laser/13 2,600 MJ 13 1/60 4dx320(2) 71,461 / 7 214,383 / 21 35

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This page originally found at http://www.elvwood.org/Traveller/FixedMount.html
Last updated: 28 July 2007