The form of a spelljamming vessel is its overall shape and design, and plays a significant role in how maneuverable the ship is. A ship designed by a spacefaring shipwright is shaped to best work with the way a helm functions, so the ship moves with the helmsman, rather than fighting him. Ships not designed to take advantage of the freedom and three dimensional aspects of space are less maneuverable.

There are three broad categories of ship form: space, terrestrial, and poor. There is no cost difference between then, nor does it take longer to build; what determines the difference is who designed the ship. Spacefaring engineers create space ships, while groundling engineers without knowledge of the workings of spelljamming create terrestrial ships. Poor designs are the results of people without any real engineering skills designing and building ships. They are also common amongst gnome ships, who think they know what they are doing.

At this point also determine the tonnage of the ship.

To illustrate how the system works, we will build a ship as an example…
   

A successful band of mercenaries and privateers have recently come into a lot of money and three major helms, and so wish to purchase some ships that can make better use the more powerful helms. They look at the standard designs, but decide to have three custom built ships, better designed for warfare. They decide to call the ship class the Tiger Shark, since they will base it on the Hammerhead.

The ship will be designed and built by spacefaring shipwrights, and so will be a space design. After some consultation, they decide on a tonnage of 60, since this allows them to maintain a slightly better Maneuverability Class.

The frame is the internal structure of the ship, the skeleton upon which all other components are built. It is the only part of this system a ship must have to be considered a ship. It is also the most important, since it determines how big the ship is, and thus how many people and weapons it can carry, and is the primary component in determining how much damage it can take.

There are two factors in frame design. The first is the materials that make up the frame; better, stronger materials make a ship more durable. They also cost more gold. Chart 1-1 has the costs by tonnage.

The second factor in frame design is how much of the material goes into the frame: the more materials you use the stronger the frame becomes, at the expenditure of gold and space. The more space used to build the frame, the less space you have in the ship to house people or cargo. There are five types of frames: light, standard, heavy, extra heavy and super heavy. Each frame type is generally found on ships serving a particular purpose.

A light frame is the lightest type, and is found mostly on ships designed to carry large amounts of cargo or on shuttles and small pleasure craft. The frame is basically just enough structure to mount a hull upon and support cargo. The lack of material saves both money and space, but drops the durability of the ship severely.

A standard frame is the most common type, used for most ships excepting those expecting to see a large amount of combat. This includes most traders and groundling ships.

Heavy frames are used on ships designed to be combat capable, but whose primary use is not always combat. They are often used as trading ships in rough territories, or as secondary trade ships providing protection to a caravan. Heavy framed ships are also the most popular with adventurers and freebooters. Some examples of heavy framed ships are the Hammership and Squidship; both can hold their own in a fight, but they also are multi-functional enough to see non-combat use.

Extra heavy frames are almost always found on ships whose primary purpose is warfare. Their lack of space and high cost make them impractical for most other purposes.

Super heavy frames are found mostly on ships made from hollowed out objects, such as the asteroid-carved Citadels of the dwarves. Super heavy frames have very thick walls, varying from two to five feet. For walls beyond this thickness, such as asteroids that have only a small percentage of their interior hollowed out, see the option Asteroid Ships in Section XV. Note that the cost for the super heavy frame assumes that the materials are being assembled like any other ship. For hollowed out objects the price may drop or rise, depending on the extent of work that needs done.

The type of frame used will affect the cost, figured as a multiplier to the base cost from material type. This is shown on Chart 1-2.

The type of frame will affect how much internal space it uses; a heavier frame uses more space. See Section X for more on internal space usage.
   

Looking over the materials available, they find that metal is far to expensive, and stone is expensive and impractical, so they stick with the standard of thick wood. An extra heavy frame seems a natural, but since they tend to carry a large number of mercenaries and supplies for them, they decide to go with heavy, so they don't have to give up on space.

At 750 per ton for thick wood, the 60 ton frame will cost 45,000 gold. Modified by the x2 multiplier for a heavy frame, the total cost is 90,000.

Rams are common weapons on warships in space, and adding one is fairly simple. To mount a ram a ship must have at least a standard frame, since a light frame is not up to taking the shock from ramming, making it likely to break off and take a sizable chuck of the ship with it. Even with a standard frame a certain amount of reinforcement needs to be done. Heavy and extra heavy ships are considered reinforced.

There are three types of rams: piercing, blunt and grappling. The cost of piercing and blunt rams is based on the frame material and the ship's tonnage, as shown on Chart 1-3. The cost of a grappling ram is different, being based only on tonnage: 200 gp per ton. In addition, 5% of the ship's internal space is taken up by the grappling ram's operational mechanics.

If the frame is standard and needs reinforced, add 25% to this cost.
   

A ram is a must for any sort of combat ship, and sticking with the shark theme they decided upon a blunt ram, with the nose as the ram. The frame is already heavy, so overall reinforcement is not needed, just the reinforcement of the nose.

The cost for this is 6,000 gold.

Whereas the frame is the skeleton of the ship, the hull can be considered the skin. It provides protection to the crew and cargo of the ship, both from attacks and the elements. Unlike the frame, there is only one type of hull. Using more or less materials is considered plating and increases the ship's Armour Rating. The only decision in hull design is type of material used. The cost for the hull, per ton of the ship, is shown on Chart 1-4.

A ship is not required to have a hull, which will reduce the cost and construction time, but reduces durability and the Armour Rating, as well as allowing attackers to target specific internal sections of the ship. It also prevents the ship from being able to land in water.
   

Again, the mercenary company would like metal, but the cost is prohibitive for the full hull. They decide to go with thick wood, and will look at metal plating later. The cost is 15,000gold.

Most ships in space have an open top deck, much like any groundling sailing vessel. This makes the mounting of weapons and rigging much easier and more space efficient. Some ships instead opt to have their ship partially or fully enclosed, reducing their deck space but increasing the ship's level of protection, and thus Armour Rating. The drawbacks of a reduction of deck size is a reduction of the amount of weapons and rigging a ship can mount without complication.

Enclosure of any kind is fairly uncommon, most often seen on ships designed either for warfare or vessels that try to avoid warfare, depending on other ships for protection, such as large cargo ships and passenger liners.

To have either partial or full enclosure the designer simply decides; there is no change in cost or construction time. Partial enclosure reduces the number of weapons a ship can carry by half. Full enclosure drops it to zero; all weapons must be mounted internal or on the hull of the ship. See Section VII for how enclosure affects rigging choices and Section IX for the affects of enclosure on Armour Rating.

It is also possible to have more deck space. This is simply a function of widening the deck while making the ship more shallow, or adding decks to other parts of the ship, such as the underside. The benefit of this is that it increases the amount of weapons that can be added. The drawback is that it decreases the Armour Rating, as flat surfaces are much worse at deflecting shots, and bigger deck makes it an easier target. See Section IX for the affect on Armour Rating.

There are two levels of deck expansion: partial and full. Partial increases the number of weapons that can be added by a third, and full increases it by two thirds. This extra deck space can also count as a second deck, usually on the other side of the ship, but this will likely preclude the ship from landing in water.

Expanded decks and enclosure are mutually exclusive.
   

The Tiger Shark will not have more than standard rigging, so they opt for partial enclosure. This will reduce the number of weapons they can mount, but they expect to mount some internally anyway. This costs nothing.

At this point the Hull Points of the ship can be calculated. To do this add…

(Hull Material Factor) x (.25) x (Tonnage)

...to...

(Frame Material Factor) x (Frame Strength Factor) x (.75) x (Tonnage)

...where Hull and Frame Material Factor is shown on Chart 1-5 and Frame Strength Factor is shown on Chart 1-6. Round all fractions normally.

If the ship does not have a hull, do not add the second portion of the formula.

The Tiger Shark has a thick wood hull, giving it a HMF of 1, and is a 60 ton ship, so plugging these into the first formula would be 1 x .25 x 60, which is 15.

The frame of the ship is thick wood, giving a FMF of 1, and is heavy, giving a FSF of 1.25. Plugging these into the second formula would be 1 x 1.25 x .75 x 60, which is 56.25. Adding the two together is 71.25, rounded down to 71 Hull Points.

Because the helm's primary use is propulsion, it makes a relatively poor steering device on its own. Nearly all ships rely on other steering devices to help maneuver the ship. Although some ships use rudders and fins rather than sails, they are all referred to as rigging. There are five types of rigging: none, minimal, standard and topped-out, all of which have an effect on the Maneuverability Class of the ship.

No rigging is just what it sounds like, a ship that does not use any sort of additional steering device beyond the helm. Almost no ship is designed this way intentionally, since it makes the ship extremely sluggish while maneuvering. Those few that are tend to be small, to offset the penalties, or extremely large, since rigging after a certain size tends to do no good. On the other hand, any ship can end up without rigging if it is destroyed or the crew are all dead.

Minimal rigging uses just barely enough steering devices to allow the helmsman to put most of the maneuvering work into the hands of the riggers. It is fairly rare, mostly found on ships that depend on other ships for defense, such as large cargo ships and transport ships beneath 100 tons, or on small pleasure and shuttle craft, which are designed to stay close to a larger base or craft.

Standard rigging is found on the majority of ships in Arcane Space, representing what is considered by most the optimal ratio of maneuverability and manpower requirements.

Topped-out rigging adds additional steering devices, but also increases the manpower to use them properly. The additional rigging allows the crew to use more specific steering devices for certain situations, which increases the Maneuverability Class of the ship. There are two drawbacks to topped-out rigging. First, it requires 50% more riggers to operate. Second, if all of these men aren't available, the ship drops to minimal class rather than standard. This is due to the fact that the rigging has been thoroughly optimized, and a lack of a few men throws the system far off.

Terrestrial Rigging is required for any ship of terrestrial origins (i.e. galleons, cogs). This will be most ships with the terrestrial design form, but there are exceptions (e.g. a ship built by a spacefaring shipwright, but has a terrestrial from due to an oddly shaped forecastle would not need terrestrial rigging). Spacefaring design ships require far less rigging and men to maneuver than do terrestrial ships, as such ships have rigging designed for seafaring rather than spacefaring, which needs more sails to function. It takes all of those sails used at their maximum potential just to maneuver in space as well as they do. Anything less and they are considered to have minimal. Ships that require terrestrial rigging cannot have topped out rigging, and standard rigging functions as minimal, but has the standard crew requirements. On ships that don’t require it, terrestrial rigging counts as standard.

Ships of 101 or more tons gain no benefit from minimal rigging; it can be added, but counts as none. At that size minimal rigging is not enough to be useful. A ship larger than 201 tons gains no benefit from any rigging,

A ship that has either full or partial enclosure is limited by the amount of rigging it can have, since decks space is the primary location for steering devices. A ship with partial enclosure can not have more than standard rigging, and one with full enclosure cannot have more than minimal rigging. The only way around this is by installing the rigging internally, which takes up space. The space requirements are all a percentage of the ship’s size, based on the type of rigging: 5% for minimal, 10% for standard, and15% for topped-out. Terrestrial rigging cannot be mounted internally.

Note that this internal space usage represents the spatial requirements for crew and the portion of the steering device they directly handle. The fins, rudders and sails still stick out of the ship and can be attacked. On the other hand, the crew cannot be directly attacked, although they can be damaged by attacks to the area they occupy.

The cost of rigging depends on the type and size of the ship, as shown on Chart 1-7

Now that the various factors involved with maneuvering a ship have been decided, we can calculate it's Maneuverability Class. Simply look up its tonnage on Chart 1-8 to find its base MC, then modify it according to its form with Chart 1-9 and is rigging type with Chart 1-10.

For a ship of 101 or more tons, the design of the ship does not affect the Maneuverability Class. At that size the design means very little. A ship of this size that has no rigging has an MC of G. The War Captain's Companion lists an MC G, but this system calls that H, with the new stats for G being shown here.

Maneuverability Class G
Hex Face Change 1
Speed Change 1
Initiative Modifier +5
Reverse Speed 1
Crash Save Modifier -4

An MC G ship must move 2 hexes forward before changing facing, if moving.
   

The Tiger Shark is a 60 ton ship, which is MC D. They are of a space design and have standard rigging, neither of which modifies Maneuverability.

Although the term "armour" tends to conjure images of things such as knights in plate mail or tanks covered in slabs of steel, all ships with a hull are considered to be armoured. The hull serves to protect the internal frame of the ship, as well as crew, passengers and cargo. A ship can also have additional materials added to the hull, improving its Armour Rating.

It is uncommon to find most merchant vessels or cargo ships with any additional plating, simply relying on their thick wood hulls to protect them. Ships that expect to see combat but are generally designed to be useful in other situations, such the Hammership and Squidship, add additional thick wood plating. Metal plating is typically reserved for ships either designed completely for combat, or as an upgrade for other ships (see Chapter 2 for more on upgrading a ship).

Another factor in a ship's Armour Rating is how maneuverable it is; a more maneuverable ship is harder to hit. It should be stressed, though, that this modification is only applicable if the ship is moving and the pilot is skilled in Spelljammer piloting. In cases otherwise, the DM should disallow MC bonuses. In cases where a ship has an MC bonus, its AR without the bonus is written in parenthesis, such as AR 4 (6)

To calculate the base Armour Rating of a ship find its hull material on Chart 1-11. This is then modified by the ship's MC on Chart 1-12.

The modification to a ship's AR for plating is shown on Chart 1-13. Cross reference the ship's original hull material with the material it is being plated with to find the final AR. This number is still modified by the ship's Maneuverability Class from Chart 1-12. The cost of plating is shown on Chart 1-14.

Finally, ships with enclosure have a bonus to AR: +1 for partial, +2 for full. Ships with expanded decks will have penalties: -1 for partial, -2 for full.

A ship is not particularly useful without passengers and crew, and those passengers and crew require space to live and work in. So does everything else that goes inside of a ship, from space for cargo to facilities for dining. This space is rated in tons, and a ship has internal tonnage equal to its actual tonnage. Note that fractions are not rounded in the internal space section, as fractional tons are still useful.

A ship's frame will take up a portion of this space. The amount depends on its type; Standard and Heavy frames take up 10% of a ship's internal space. Light uses 5%, Extra Heavy uses 20%, and Super Heavy uses 30%. Remember, also, that a grappling ram takes up 5% of internal space for it's operational mechanics, and the space for the crew to operate those mechanics. Beyond this, the designer must decide to do with this free space. Space for the crew to rest, and eat in, as well as space to prepare food, is generally considered minimal.

Below are the descriptions of rooms and their uses. How much space they use and the cost is shown on Chart1-15. It does not include internal weapons, the rules for which are found in Section XI. Note that these numbers all include the various hallways used to access rooms, and thus the space allocated does not necessarily translate into exact room size for most rooms. Allocating one ton to am officer’s room does not mean the room itself is exactly 2700 square feet, as the one ton includes hallway space. The GM will have to determine the actual space of a room, should it be deemed necessary, but the basic rule of thumb is that a room is 75% of the space allocated to it. Cargo is an exception to this; the space allocated to cargo is the actual space available.

Keep in mind the minimum crew requirements when assigning internal space, and remember to include space for additional men that might be needed, such as cooks, astrogators, helmsmen, weaponeers, marines and passengers.

Note that these rooms are just examples, and the numbers can be tweaked with the approval of the DM. In particular, the space devoted to any of these rooms can be increased. If the designer is the captain and wants a 4 ton room, he can have it.

Anything not specifically allocated to a room becomes cargo space, which costs nothing.

Normally little consideration is given to weapon design when designing a ship, since most weapons are mounted on the deck of the ship, and is easily done post-construction. There are, though, a few considerations for certain specific situations.

A ship can normally have up to one half of its tonnage in weapons; each weapon has a tonnage rating. The ship’s deck type may modify this; see Section V Decks and Enclosure. The tonnage ratings for weapons can be found in Chapter 3. There are two options for surpassing this: mounting the weapon on the hull, off of decks, or mounting them internally. For the former, see Chapter 3.

Adding weapon space internally during initial construction is simple: the tonnage the weapon and its crew takes up is shown on Chart 1-16. The cost of these rooms are based on the cost of the hull, since shutters must be built into them. The cost is 25% of the cost of the hull material, per ton of the weapon. It should be noted that these tonnage numbers are not the same as in Chapter 3, as it includes space for the crew and factors in the ways in which it is used (i.e. catapults take up more space since there needs to be room for their arms, which is not a factor when on an open deck).

These prices do not include the weapon itself; it is merely a specific room for weapons. It is possible to mount smaller weapons in rooms meant for larger weapons, though not vice versa. It is also possible to mount weapons of different types in space meant for other weapons, as long as it is at least 2 tons less in space requirements.

By default, a ship is only capable of docking on a gravity plane or a special dry-dock; the capability of landing on either water or ground requires additional construction.

Water-landing capability requires that the hull be sealed, which can only be done for wooden or ceramic ships, unless magic is used. The cost of this is 50 gold per ton. It also requires approval of the DM, based on its shape. Some ships are not shaped properly and will capsize even if the hull is sealed. Some examples of these are the Cuttle Command and the Dolphin.

There are two forms of ground-landing capability: partial and full. The difference is in the type of ground they can land on. With partial ground-landing a ship can land on any clear, mostly flat surfaces without trouble. Any other kinds of surfaces can cause problems such as tipping over (as determined by the DM). Partial landing is mostly a function of reinforcing the hull and frame to support the weight of the ship. The cost depends on the frame type of the ship, as shown on Chart 1-17.

Full landing allows a ship to land on most fairly clear land surfaces, including hilly or mountainous areas. Full ground landing typically requires the addition of landing struts, like those seen on the Wasp. See chart 1-17 for costs.

A ship without landing capabilities that tries to land on ground risks serious damage. The helmsman must make a roll versus Spelljammer piloting, as well as a save for the ship against crushing blow. If both are made, the ship takes no damage for now. If both are failed, the ship loses 10% of it's hull points; if one is missed while the other is made, the ship loses 5%.

Every 24 hours the ship must save again, or lose 5% of it's hull points. As long as the ship does not move, this damage tops out at a total of 40% (including from the landing itself). Landing a second time starts it all over again. A ship with a heavy frame saves at +2. Extra-heavy frames save at +4.

At this point the designer can add other equipment from Chapter 4 (as of yet non-existant), or from other books.

At this point the ship itself is complete. The only thing left is figuring out a few other important statistics.

Minimum Crew
The minimum of crew required to run the ship is based on its rigging. This does not include things such as the captain, officers, support crew, weaponeers or other crew not necessary to flying the ship, nor does at include the helmsman. See Chapter 5 for more on crew. Chart 1-18 indicates the minimum number of riggers needed, based on ship size and rigging. Round all fractions up.

These numbers are how many riggers are needed to fly the ship at any one moment, but almost all ships carry extra men as back up, or for extra shifts. The actual number of extras carried varies; see Chapter 5 for more.

Saving Throws
A ship normally makes saving throws based on its hull material, but the GM may occasionally require the save based on frame material. Both should be noted.

Air Supply
Air Supply is the number of man-days of air the ship carries within its gravity. A ship can support one man for four months with fresh air for every ton of the ship. To find out the number of man-days this equals, multiply the ship's tonnage by 120 (days in four months). Every day a ship has to rely on its own air envelope, subtract the total number of air-breathing crew from this. If this number drops to zero, the air is considered stale. The ship then has the same number of stale man-days of air. After that the air turns deadly. See the Concordance of Arcane Space for more on the effects of stale and deadly air.
          

The Tiger Shark is a 60 ton ship with standard rigging, and so needs 6.

The players note down the saves for thick wood.

At 60 tons, the Tiger Shark can carry 7200 man-days of air. If they are carry a full crew with all their mercenaries, typically 79 men, they could go 91 days before their air became stale.

These are various options that can be used during ship construction. They tend to be either options that add a layer of complexity, or things that the DM might not want to allow in his games.

Composite Hulls
It is possible for a ship to have a composite hull, where different sections are made from different materials, such as a metal aft and a wooden fore, rather than one material over another. This can be used to protect specific portions of the ship, or to add a bit more durability. To do this simply decide how much of the ship's tonnage each material covers, finding the appropriate cost of each. Add these two together, plus 5%, for the final cost.

To calculate hull points for a ship with a composite hull, perform the second equation of hull point calculation for each section, adding the results together. For example, a ship with 20 tons of stone and 40 tons of thick wood would have 16 points from the hull, 6 (20 x .25 x 1.5) from stone and 10 (40 x .25 x 1) from the wood. Do the same thing if it has a composite frame.

Having a composite Hull can affect the ship’s Armour Rating. Use the AR of the material that makes up the majority of the ship, using the worst if it is an even split. Then move the AR of the ship one step closer to the secondary material's AR, unless this new rating would be equal to the secondary material's AR. For example, a ship with 20 tons of wood and 5 of stone would have an base of 7, from the wood, moving one closer to stone, for an AR of 6. If instead of stone they used ceramics, there would have been no bonus. A ship with a composite hull only gains this bonus if the superior material makes up at least 25% of the hull; you don't get a bonus for having only 10% of your ship hulled in metal. This bonus only applies for general attacks, though. Any area of a ship, if specifically targeted, has the full AR of the material it is composed of. This is why some ships will still hull certain smaller areas with better materials, such as a helm room or captains quarters.

Also, a ship gains additional Hull Points from superior materials, regardless of the area it covers, if it is at least a ton.

See Section IX for more on armour.

Ironwood
Ironwood is a rare type of tree that is known to grow on several worlds, including Toril, Oerth and Mystara. It is extremely dense and resilient, and while not capable of taking as much punishment as iron, is far stronger than normal wood. It is an eagerly sought after material for ship building. It is extremely rare, though, and is rarely found in groups; ironwood trees are typically found spread out across large areas in deep forests. This makes it hard to lumber.

The density of ironwood makes it impossible for most people to use it. It dulls axes after only a few chops, making normal lumbering techniques useless. The only way to cut and use ironwood is through magic.

Ironwood has an HMF and FMF of 1.5 for calculating Hull Points (see Section VI), and has the same Armour Rating as Stone. Ironwood hulled ships can be made water landing capable.

The cost of ironwood will vary widely, if it can be found at all. Few places will have it in stock, or even be able to get it. Three times the cost of Thick Wood should be considered the absolute minimum, and six times the cost is typical. It is also quite expensive to repair.

Composite Frames
While ships with composite hulls, made up of more than one material, are not uncommon, ships with composite frames are extremely rare. Most shipwrights see little use for it, and building a composite-framed ship can actually be dangerous. It is possible, though, and there are two types.

• Split Frames: these are ships that have two or more materials making up distinct sections of the ship, such as a metal aft and a wooden fore. Experienced space shipwrights will never purposely build a ship like this, and recommend against it to demanding customers. The reason is due to the problems with the point where one material joins the other. Such locations are more vulnerable and fragile than contiguous-material ships. Experienced captains will focus their attacks on such locations. Such attacks receive penalties for targeting specific locations, but if damage equal to 20% of the ship's Hull Points is amassed due to such attacks, the ship will split.

To find the cost for split frames simply find the cost of each section, then add them together, plus 10%.

• Shell Frames: More common than split frames, they are still very rare, A shell frame is a frame of one type of material wrapped around a frame of another material, completely or mostly enveloping it. This is done to protect certain key areas of the ship, such as cargo vaults or the helm room. The Hull Points are figured the same as for the split frame, but it does not have the drawbacks. The cost is figured the same, except add 20% to the total.

Shell Ships
Despite the name, this is not ship made from a giant seashell, but rather a smaller ship than somehow fits into a larger ship, in some sort of mooring cradle, and becomes its motive force. For example, a small 10 ton all metal ship could be built and outfitted with a major helm. Then a 90 ton ship with a sort of socket that the smaller ship fits in and is moored to could be built. As long as the smaller ship was firmly attached to the larger, it could propel and maneuver the entire ship as one. Then, if the larger ship becomes severely damaged, the smaller ship can be used as an escape craft.

To design such a craft build both ships, but the larger ship must designate a portion of its volume to holding the smaller. How much space is up to the designer, but the less space devoted, the more of the smaller ship's volume will be revealed, and the less sturdy the connection will be. Thus it may be possible to target the smaller craft and damage it. The DM determines the hit penalty to strike the moored craft based on how much is revealed. The larger ship does not count the mooring space in its volume when it calculates hull points. The designer could even allocate no tonnage, but the ship would then simply be lashed on, which is precarious at best.

It is possible to build two equal sized ships this way, with one being the propulsion unit.

Note that the shell ship is different from the shell frame in that it is actually considered two different ships, and do not combine their Hull Points.

Solid Mass
There are times when a ship wishes to add a large amount of bulk to a ship, without actually adding any usable space, to reduce the cost. The most common reasons for this are to increase a ship's gravity field, and thus air supply, or to achieve a certain appearance or motif. A good example of such is the Octopus, whose tentacles add a fair amount of mass, but no space.

This option is rarely used in ship construction, as it is not deemed particularly useful. While it would seem that the solid mass would add a fair amount of hull points, the truth is that on most ships the parts that are not solid mass are large enough to be targeted without penalty, and most ship crews of any appreciable experience can recognize this, and simply target the normal mass of the ship.

Solid mass sections of a ship have 5 times the hull points of a normal section with an extra heavy frame and a hull made of the same material (multiplied before rounding). So, a 10 ton section of solid (thick) wood would have 68 hull points. These hull points are calculated and kept separate from normal hull points. It will have an Armour Rating as a hull of the same material, plated with that material, plus 1. Solid mass has no internal space to be used, but decks can be built upon it, so the space does count towards weapon capacity.

The cost of solid mass varies, by material type. The cost of stone and wood is actually cheaper, as less work is needed to prepare the mass, while metal and ceramic is more expensive, as the cost of the material outweighs the reduction in work. Costs also do not include any magics or work needed to shape the wood into the desired form, such as with the Octopus' tentacles. The Woodcraft spell, though, is often used for this purpose, and its low level makes it common and cheap.

The penalties to hit the non-solid portions of such ships are determined by the DM, but ships with 10 or more tons of solid mass rarely have any penalties. If a ship does not target a specific area of the ship, roll randomly to see if the shot hits the solid or non-solid portion, based on percentages. For example, a 60 tons ship that has 20 tons of solid mass has a 33% chance of being hit in the solid portion.

Bone has no price listed as the only way to have solid bone mass is to find bones of sufficient size, which are very rare, and typically not found for sale. Ceramics would be even harder to find as a solid mass, and no mundane procedures could create it. Magical creation is possible, such as those known by the elves, but the DM will have to determine the prices based on the situation. The price of metal reflects the difficulty of using mundane means to create a section of ship 2,700 cubic feet in volume.

Asteroid Ships
Although some dwarven Citadels and similar ships can be created through the use of the super heavy frame, there are times when only a small percentage of the internal "space" of an asteroid or similar body is used. For example, a 20 ton rock that has a 2 ton helm room and a 3 ton cargo room, with all other facilities being on the surface.

In cases like these, instead of bothering with the frame at all calculate all non-used space as solid mass (as per the option, above) for calculating hit points. So, in the case of the 20 ton rock with 15 tons of non-used space and a super heavy frame, the ship would have 167 hull points. This may seem like quite a large amount, but considering how much solid mass this really is, as compared to a hollow shell — 40,500 cubic feet of solid stone — it makes sense.

As for armour, the ship is considered to be plated with the material it is made of, plus a bonus of one to account for the thickness of the hull, like a normal solid mass section. Most such ships are also at least partially enclosed, and often fully enclosed.

These type of ships typically have no rigging, but it can be added. The cost is doubled, since adding masts and such will require extra work. Unless extensive work is done, an asteroid ship is going to be of Poor design, and thus not particularly maneuverable. It might be possible to find a rock that could be classified as Terrestrial, but they are going to be quite rare. Anything beyond this will take radical redesign work.

Cost for such asteroid ships will be based more on mining costs than actually ship building costs, and is likely to be more expensive, especially if nice, flat walls and squared rooms are used. This should also be taken into consideration for other aspects of ship building and modification. For example, adding internal weapon may require some additional mining work to open a hole to fire through. Another example is landing capabilities: many asteroids will be fully capable of landing on the ground without paying for it, but are unlikely to land straight, due to odd their shape.

Ram Rings
While a ship with a ram has been designed to take the shock of impact, the people on board haven't. Those unprepared for the ram will typically be tossed around and stunned, sometimes even wounded. To help prevent this most ships with rams will have a large number of ram rings mounted throughout the ship. These are simply rings bolted to the walls and ceilings, in a manner similar to cargo rings (and are actually the same thing). They provide solid handholds for crew during ramming.

Properly outfitting a ship with ram rings costs 5 gp per ton of the ship that is not devoted to cargo. Cargo space already has the equivalent of ram rings.

Strengthened Internal Bulkheads
Unless all of its internal space has been categorized as cargo, a ship is going to have bulkheads (walls) throughout, and a ship designer may want to strengthen some of these. The most common use is for security of vital areas. The cost of the strengthened bulkhead depends on the materials being added:

A one ton cube has a surface area of about 1165 square feet.

Ceramics
The term "ceramic" in Spelljammer can be misleading as it does not refer to actually ceramics as most know them. It is instead a sort of catchall term for materials that have similar properties. Ceramics are good for deflecting shots, being rather hard, but aren't as good at taking actual damage, having a resiliency similar to that of thick wood.

The most common ceramic found in Arcane Space is the plant used to construct the ships of the Elven Imperial Fleet. Created by magically altering a spaceborne plant, this material is still alive and continues to grow. Some other examples of ceramic materials are the shells of large sea creatures, such as used for the gnomish Whelk, or the hardened silk excretions used to create the ships of the arachnid aranea.

The cost of ceramics materials listed for hulls or frames assumes the builder is acquiring his materials from someone else rather than creating it on their own. The elves, for example, do not pay 6,000 go per ton, but rather grow it from a seedling. The cost for those capable of creating their own ceramics vary, from 1,000 per ton for the elves, to free – but very time consuming – for the aranea.