A ship’s hull is much more than a wall keeping air and stuff inside and vacuum out. Unfortunately I haven’t found a lot about hulls and the way they affect their ships. Classic Traveller started out with two types of hulls: streamlined and not (the default.) Streamlined hulls could enter atmosphere or even refuel in the atmosphere of a gas giant. Other hulls could not enter atmosphere.
That means for practical purposes only streamlined ships could land on worlds with 8000 kilometer or greater diameter. Larger than that and they had to have at least a trace atmosphere.
Then High Guard came out and gave us oodles of new ship hull types. We now had partially streamlined as well as some descriptions of general shapes. We now had wedges, needles, cones, and flattened spheres (saucers!) for streamlined hulls. Cylinders, spheres and close structures were partially streamlined and dispersed structures and planetoid hulls were not streamlined in any way.
We now learn that streamlined and partially streamlined hulls can refuel from gas giants. Streamlined ships can land on any world. Partially streamlined ships can land on any size 0-1 world. Other types can’t land.
I was going to start introducing all kinds of devices like contra-grav, wings, thruster variations and such. Then I chucked it because the three types of hulls work fairly well as is.
Where the system breaks down is it doesn’t differentiate between the hulls much. You get a price modifier, a description and a defense against meson weapons. In MTU beam masers are cutting edge and meson guns remain science fiction. I still want a bunch of ship types. So here are my tweaks.
Type One Cost Mod: +20% Description: Needle/Wedge Streamlined
This is the ultimate in streamlining. This hull can refuel from a gas giant in one pass, dropping into the deeper regions of the atmosphere. The hull can hover indefinitely and has extensive control surfaces (possibly wings.) Flying this ship in atmospheres of 2 or greater gives the pilot a +2 DM to all rolls. This hull can launch one small craft per turn per 10,000 tons.
Type Two Cost Mod: +10% Description: Cone Streamlined
The conical hull is not as maneuverable as a wedge or needle. It is cheaper. Refueling from gas giants requires 1D3 passes. Because the hull is sloped the ships receives a -1 DM to be hit in combat. Ships can hover on worlds whose size code is no more than double their maneuver rating (so a ship that can make 4 gees can hover over a size 8 world.) This hull can launch one small craft per turn per 10,000 tons.
Type Three Cost Mod: 0% Description: Cylinder Partial Streamlining
The cylinder design is built for deep space operations. It can scoop fuel from gas giants taking 1D6 passes. It might even land on size 3 or larger worlds by standing on its tail and thrusting directly downward but this is not a stable configuration. The ship’s control systems are not made for it (10+ to hover or land + Pilot skill, -1 if world size 5, -2 if world size 7 and -3 if world size 9 or larger.) Other maneuvers in an atmosphere are at -1 DM. This hull can launch one small craft per turn per 10,000 tons.
Type Four Cost Mod: -40% Description: Close Structure Partial Streamlining
A close structure removes the engines and generators from the main hull and sticks them on booms. This trades distance for radiation shielding saving on mass and cost. generally speaking you want the stuff on the booms and arms to be securely fixed despite what you see on Firefly. This design can refuel form a gas giant in 3D6 passes. It can launch small craft very easily, generally 2 small craft per 10,000 tons or less.
Type Five Cost Mod: -30% Description: Sphere Partial Streamlining
The sphere is able to refuel from gas giants with some difficulty due to the wind resistance its shape creates. It refuels by skimming the highest reaches of the atmosphere and takes 2D6 passes. In space the sphere can pivot in any direction with equal speed and presents the smallest target for a given volume giving it a -1 DM to be hit. This hull can launch one small craft per turn per 10,000 tons.
Type Six Cost Mod: -20% Description: Flattened Sphere Streamlined
The classic flying saucer makes its debut in CT. This also covers oblate spheroids. Unlike the plain vanilla sphere the type six has a bunch of thrusters and control surfaces to let it operate in an atmosphere. Unlike the type one and two it receives no bonus to operate in an atmosphere. It can hover with the same restrictions for the type two. Flattened spheres require 2D6 passes to refuel from a gas giant. This hull can launch one small craft per turn per 10,000 tons.
Type Seven Cost Mod: 0% Description: Dispersed Structure Not streamlined
Dispersed structures and most planets do not mix well. These vessels are much longer than their tonnage would indicate. Engines and generators are placed very far from crew and cargo sections letting the ship use very little shielding to protect the crew. The radiation hazard from these sections make EVA activities (like boarding actions) dangerous to vacc suited crew. A dispersed structure might be able to land on a size S world. It risks tearing its radiators panels, sensor arrays, and similar systems off. Dispersed structures carry all their small craft on their hulls in recesses. All craft can launch in a single turn making them excellent carriers.
Maneuvering a dispersed structure in space is no joke. A long skinny ship has a huge arm of momentum and turning without warping structures must be done carefully. This hull is +1 to be hit in combat and has a -1 DM to all pilot rolls.
Type Eight Cost Mod: 0% Description: Planetoid
Planetoids are essentially free. The bad news is tunneling and carving compartments costs 1000 cr. per ton. The planetoid also requires 20% of its space be used for structural purposes. Boarding actions on planetoid ships are a joy for the attackers. There’s plenty off bulletproof rock walls for defenders to duck behind. Think dungeon in space. If you aren’t using High Guard planetoids are -1 DM to be hit due to natural armor. Forget about tight maneuvering. This hull can launch one small craft per turn per 10,000 tons.
Type Nine Cost Mod: 0% Description: Buffered Planetoid
Buffered planetoids have 35% wasted space to provide the ship with armor. If you aren’t using High Guard planetoids are -2 DM to be hit due to natural armor. This hull can launch one small craft per turn per 10,000 tons.