Technology 108 - The Hull and Internal Bulkheads

The hull is perhaps the most obvious feature of a ship, defining it's overall shape and colour. Combined with the internal bulkheads and members it forms the structural skeleton and skin of the vessel.

Structural members

These are the very first thing laid down in a shipyard, and comprise the skeletal structure onto which everything else is attached. They are the strong core which to a large extent determines the health of the ship.

Structural members comprise a lattice of strong metal frames. These frames are often hollow, to save weight and to allow field emitters to be slung inside them, making them stronger still. Sometimes the main skeletal structure (the spaceframe) is joined to smaller sub-structures that are either lighter to give certain areas a different level of protection, or stronger to provide local extra strength for special systems. The SIR is often mounted within a structural frame designed to protect it from impact, for example.

The spaceframe is designed to hold the ship in its correct shape under given stresses that the designers have calculated. It is an unavoidable fact of physics that a ship will resist acceleration from the engines, and this generates compression stress within the frame. Ships are designed to acept a certain amount of compression stress, and usually with generous leeway for alterations and upgrades. It must be observed that these stresses are limited and are often the reason why a given ship cannot exceed certain values of speed and acceleration.

All other componants and elements that make up the ship are bonded to the spaceframe by a wild variety of methods.

Upgrading a spaceframe is invariably a much more difficult task than building a new ship, and commensurately costs a great deal more, for this reason alone tampering with one is foolish at best.

There are a very great number of destroyed ships that were lost solely because a captain decided to cut through a load-bearing member - ships can rarely survive having their key strengths removed.

Internal Bulkheads

Inside the ship there are several types of rigid structure. Bulkheads form upright surfaces within a ship to define discrete areas, or to protect users from exposure to various bits of engineering. Decks are horizontal plates intended to provide a smooth surface to walk on, as well as most often inducing the AG field. Deckheads are the under sides of decks and are a common location for various passive features (such as lights, air conditioning and other sundries) to be placed as they rarely intrude on the occupant's space.

The internals are often designed with a certain amount of 'crush' and can distort to a degree whilst retaining an airtight seal.

Rearranging internal bulkheads isn't especially tricky, but two things must be remembered;

A - Hatches are very difficult to move.

B - Structural Members ought never be touched, let alone moved.

The Hull

What is referred to as the hull is generally several layers of actual skin and systems.

The innermost layer is a thin metal form designed to provide the correct outer shape on one side, and house fittings to join the spaceframe on the other. These pieces are often quite large, and provide the basic airtight seal. Most external devices (such as landing gear and sensors) do not pass through this layer instead bolting to it. Most designers try to keep penetrations of the inner layer to a few power and command and control (C&C) lines. Obviously external hatches, cargo loaders and airlocks all have to go through, too, and in practice the inner seal often ends up looking like a collander, but IN THEORY, it is breeched in only a few places.

On to this layer a gridwork of frames, spacers and supports is grafted. These define spaces within the skin of the ship for needed systems and generally are around thirty centimeters thick. A lot of this space is given over to fuel tanks in most designs.

Any ship system that needs to protrude from the hull is fixed here. A well designed ship will tend to have redundant power cabling and various C&C conduits so that repairs can be affected more easily, as threading new cabling is extremely time consuming (because you're working in a gap a few centimeters think and covering the whole hull) and dangerous (because unless the seals are perfect you're going to be letting air escape).

Many designs feature power and control 'hubs' where almost any number of devices can be attached and powered without needing new cables. These features tend to be gaps between the outerskin and the inner seal, and if their covers are left off look like pits and dips in the hull.

The outer skin is much stronger than the inner seals. This is bonded to the external framework and the inner spaceframe with strong molecular bolts. The outer hull is designed to protect against bangs, crashes, scrapes, impacts, blows, dents and angry people.

On top of the outer skin some designers and many end users attached panels of armour. This is usually excess sheet metal cut and welded to provide greater resistance to adverse forces than the outer hull alone.