Citizens of the Imperium

Citizens of the Imperium (http://www.travellerrpg.com/CotI/Discuss/index.php)
-   The Fleet (http://www.travellerrpg.com/CotI/Discuss/forumdisplay.php?f=16)
-   -   Hardpoints and surface area (http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=3797)

mike wightman April 9th, 2005 12:13 PM

What if hardpoints and their associated weapons were limited by available surface area only?

No need to worry about EPs and all that, can you fit them on your hull and in your hull?

A bit like LBB2 really ;)

I dug out FF&S and put this together:
hull..hp
100 2
200 3
300 4
400 5
500 5
600 6
700 7
800 8
900 9
1000 9
2000 14
3000 19
4000 23
5000 26
6000 30
7000 33
8000 36
9000 40
10000 43
20000 66
30000 86
40000 106
50000 123
60000 140
70000 156
80000 170
90000 183
100,000 196
200,000 313
300,000 406
400,000 495
500,000 576
600,000 650
700,000 720
800,000 786
900,000 850
1,000,000 913

1 hardpoint can mount either a 1 ton turret, a 5 ton barbette, or up to a 35 t weapon bay.

50 and 100t bay weapons cost two hardpoints to install.

Note, one hardpoint requires 300 square metres of hull area. I chose this so that the Gazelle becomes legal ;)

My idea is to use this table for LBB2, High Guard, and T20 design systems. TNE, and T4 already use surface area in their design systems.

edited note - GT:ISW does something like this :) with the configuration modifier that pops up later in the thread which I will add now for completeness - thanks to Dan :)
hp mod
x2.0 for Open Frame/Dispersed
x1.3 for Needle
x1.5 for Slab/Wedge
x1.1 for Cylinder
x1.2 for Box
x1.0 for Sphere
x1.2 for Disc/Flattened Sphere
x1.4 for Close Structure

The Oz April 9th, 2005 09:52 PM

Shouldn't the available surface area be altered by the hull configuration? A sphere is the space with the least surface area for a given volume (as my old geometry textbook says) and so I'd think there'd be more surface area available for other shapes.

Does this seem like a reasonable order to put the HG configurations, from lowest surface area/hull volume ratio to the largest?
Quote:

Configuration (HG USP Code)
Sphere (5)
Planetoid/Buffered Planetoid (8/9)
Flattened Sphere (6)
Close Structure (4)
Cylinder (3)
Cone (2)
Needle/Wedge (1)
Dispersed Structure (7)
I'm sure it's possible to calculate the relative "efficiency" of the configurations in giving surface area per unit volume, but I'm too tired to play with that tonight.

far-trader April 9th, 2005 11:26 PM

I also think that a couple other big features should impact usable surface area/hardpoint availibility.

Externally mounted craft and drop tanks. I'd say lose half the hardpoints for civilian ships. Military ships might get away with a system of structural bracing to avoid the loss of hardpoints but probably at the cost of lost volume.

Large hatches such as for small craft bays and cargo holds. I'd say 1 hardpoint lost per such feature on civilian ships. And again military ships could avoid the loss of hardpoints with added structural bracing.

Just a couple thoughts.

far-trader April 9th, 2005 11:28 PM

As for the surface area of different shapes you're corrrect but I think a single surface area rating based on the most efficient shape might serve well enough. Yes your flat shape has more surface area than a sphere but is it all useful surface area?

far-trader April 9th, 2005 11:47 PM

Ah, it was my own house rule [img]smile.gif[/img]

I was just checking FF&S1 because it has the shapes and modifiers and surface area. However the way it did surface area didn't take the shape into account. Unless it was some errata I missed.

Surface area was strictly 100 times the material volume which was based on displacement. I added the material volume modifier from the configuration table, as well as for the streamlining (x1.0 for US, x1.1 for SL, x1.3 for AF). FF&S1 only modified the surface area for Airframes (to account for the lifting surface/wing area).

So, for what it's worth, using the FF&S MVM as a guide for the surface area of the configurations:

2.0 for Open Frame/Dispersed
1.3 for Needle
1.5 for Slab/Wedge
1.1 for Cylinder
1.2 for Box
1.0 for Sphere
1.2 for Disc/Flattened Sphere
1.4 for Close Structure

Except for the Open Frame/Dispersed hull form all the others are fractional and round down to 1 if you don't want to be fussy. And the Open Frame/Dispersed hull form while having more surface area may not be the most useful of surfaces, much of it pointing inside at your other hull structures [img]smile.gif[/img]

mike wightman April 10th, 2005 02:10 AM

Quote:

Originally posted by The Oz:
Shouldn't the available surface area be altered by the hull configuration? A sphere is the space with the least surface area for a given volume (as my old geometry textbook says) and so I'd think there'd be more surface area available for other shapes.
Yep, the tables are for spherical hulls and configuration should be taken into consideration, I just haven't got around to that bit yet ;)

mike wightman April 10th, 2005 02:12 AM

Quote:

Originally posted by far-trader:
I also think that a couple other big features should impact usable surface area/hardpoint availibility.

Externally mounted craft and drop tanks. I'd say lose half the hardpoints for civilian ships. Military ships might get away with a system of structural bracing to avoid the loss of hardpoints but probably at the cost of lost volume.

Large hatches such as for small craft bays and cargo holds. I'd say 1 hardpoint lost per such feature on civilian ships. And again military ships could avoid the loss of hardpoints with added structural bracing.


Two very good ideas.

castlebravo April 10th, 2005 02:15 AM

Sigg- I think your surface area vs. hard points ratios are right on the money.

Quote:

Originally posted by The Oz:
Shouldn't the available surface area be altered by the hull configuration?
I calculate surface area by configuration. I also try and estimate surface area based on a configuration of multiple substructures. So one ship is built around a number of basic geometric substructures. For instance a single ship might be three large cylinders (cargo holds/propulsion systems) mounted underneath an oblong box (main superstructure) with another smaller oblong box mounted on top (forecastle/bridge decks). I use the general dimensions of the substructures to calculate total dimensions, mass, volume, surface area. I also try and guesstimate the number of hard points that can engage by direction or line of sight—bow guns, stern guns, port guns, starboard guns, dorsal guns, and ventral guns—based on the layout of the substructures.

Quote:

Originally posted by far-trader:
I'd say lose half the hardpoints for civilian ships.
For me, this is not a engineering rule, but a design consideration. Civilian ships have less mounted weapons because the ship is not intended for combat, but for economic profit. Every credit spent on weapons and their associated systems and supplies makes a civilian ship less profitable. There is an implicit economic impulse to only mount the number of weapons absolutely necessary for self-protection. Since there is no physical/engineering reason why the surface area couldn’t be used for a mounted weapon, there should not be a engineering rule that demands it. In other words, don’t tell the naval architect how to suck the egg. He is compelled not to use hard points anyway.

Quote:

Originally posted by far-trader:
Large hatches such as for small craft bays and cargo holds.
Agreed. I also think sensor and communication arrays, and propulsion nozzles should reduce available surface area and therefore available hard points.

mike wightman April 10th, 2005 02:16 AM

Quote:

Originally posted by far-trader:
So, for what it's worth, using the FF&S MVM as a guide for the surface area of the configurations:

2.0 for Open Frame/Dispersed
1.3 for Needle
1.5 for Slab/Wedge
1.1 for Cylinder
1.2 for Box
1.0 for Sphere
1.2 for Disc/Flattened Sphere
1.4 for Close Structure


And this saves me some effort, thanks Dan ;)

mike wightman April 10th, 2005 02:28 AM

Quote:

Originally posted by Castlebravo15:
Sigg- I think your surface area vs. hard points ratios are right on the money.
Thanks [img]smile.gif[/img]

Quote:

I calculate surface area by configuration.
<snip of useful stuff>

What I was aiming for was an alternative way to balance the number of weapons available to a ship, without having to track EPs for the weapon systems.
Following some excellent suggestions I'm wondering if max. hull hardpoints can be used as a much more versatile accounting system in simple ship design?

Quote:

For me, this is not a engineering rule, but a design consideration.
<snip again>

I agree completely.
Quote:

I also think sensor and communication arrays, and propulsion nozzles should reduce available surface area and therefore available hard points.
More to add to the list ;)

Thanks for the feedback.


All times are GMT -4. The time now is 09:25 PM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright (c) 2010-2013, Far Future Enterprises. All Rights Reserved.