3e SJ combat and needed stats

I expect we can all agree it would help our cause if we used the
official WotC rules for our combat system: either Arms&Equipment
vehicles, Stormwrack narrative combat, or d20 Future spaceship combat
rules. 1) a narrative system is good for groups that prefer their
characters to matter - boarding actions are the interesting part.  2)
the d20 future rules give all ships perfect manueverability, a distinct
break from SJ feel.  3) the Arms &Equipment vehicle rules use sectional
hitpoints that get burdensome quickly.
So I'll try to use overall 'fastplay' hitpoints for ships.  The rest of this info applies regardless.
For those who would prefer to keep hull points, see also Mongoose
publishing's Seas of Blood that gives ships structure dice based on size
and type.

For those who wish to capture vessels, I recommend the narative combat system be used.  

To fit with 3e combat systems: (many references to Stormwrack/Arms&Equipment Guide for similarities)
Speed: 1SR = 150ft move speed
MC:  new manueverability    Shiphandling check modifier (for narrative system, and ramming/crashing checks)
                                                                   turn
distance45  turn60    speed change: space    speed change atmosphere
    A        airial poor                 +6                         5
10                 3SR                               100ft*
    B        airial clumsy             +4                        10
25                 3SR                                50ft*
    C        nautical good            +2                        30
40                 2SR                                20ft
    D        nautical average        +0                        60
75                 2SR                                10ft
    E        nautical poor             -2                        120
150                1SR                                  5ft
    F        nautical clumsy*        -4                        240
300                1SR                                  5ft
notes: turn distance is the amount that must be moved between turns of
45 or 60 degrees (squares and hexes), ships still get a free turn at the
end of the round.  Turning does not cost speed (as 3e), but it is
noteworthy that the cost of turning in a 150' hex works out very close
to the distance that must be travelled while making that turn when
measured in much smaller units.
'nautical clumsy' does not appear in the books, but is extrapolated from the others
speed change is not listed for airial manueverabilities, and is thus
extrapolated since ships can't brake as fast as anything with wings.

Ramming and Crashing:
    a ram is now resolved by opposed SJPilot checks (plus shiphandling
modifier), the attacker must at least match the defender's check to
succesfully ram, head-on rams may still be responded to in kind.
    Crashes can be avioded by the helmsman making a SJPilot check (plus
shiphandling) DC 15 Huge, 20 Gargantuan, 25 Collosal, 30Collosal+, etc.
The damage is dependant on the speed and size of the active vessel, that
being the ramming ship or the smaller in a crash
    large 1d6, huge 2d6, gargantuan 3d6, collosal 4d6, collosal+ 6d6 per SR (or 10ft on water)
    a ramming ship takes only a quarter this damage (SJ rams are more
integrated into the frame than nautical rams, which take half)
    both vessels suffer Ship Shaken, and other crits as appropriate

new skill: SJPilot (trained only, Wis, see below) -
    used to perform special manouevers while at the Helm
    normal combat is a DC 10 standard action to maintain control
<untrained may do so as a full-round action><trained can always take
ten>
    DC 15 move action to add a +2 dodge bonus to your ship's AC (rises
by +1 if you also have 5 ranks in K(archetecture&engineering))
  special: if you are a spellcaster with 5 ranks in Concentration and
are using a spell-draining (standard) Helm, use your casting stat
instead of Wis.
    some specific Helms will use Dex as their prime stat (theese are mostly non-magical)
    synergy bonus from and to Prof(Sailor), and from Concentration

Ship weapons: double reload time, keep crew requirement
range increment of 'Range' x 30ft [the table presented is good for
balance, but not very sensible physics - heavy weapons are only a tiny
bit slower than light, there is that much more force involved]
    or balistae 150ft, catapults 100ft, bombards 50ft, Jettisons 50ft, fire projector 100ft line
the projectile then moves 5 increments each round forever (except jettison shot disperses after 10 increments)
        once the projectile succeds on a touch attack against an air
envelope (one size larger than the ship), it stops.
Attack roll = crew leader's Bab+Int (balistae and fire projectors use
Bab+dex)    {balistae are mounted in such a way that the weapon can be
aimed by one man's strength, most weapons require guesswork on pullies
and wedges} - since all weapons are actually direct fire they only need
to match the AC of the target
    or just use Bab+dex for all attack rolls
Stray projectiles make attack rolls using only magic bonuses on the
ammunition itself to hit any ship whose space they enter, the helmsman
adds half his ranks in SJPilot as dodge bonus versus theese stray due to
advance warning.
                                      dmg    ROF    crew    ship threat    personell threat
        Light Ballista            3d8     1/4        1            -                    19-20
        Medium Ballista       4d8      1/6        2          20                   19-20
        Heavy Ballista          6d8      1/8       4          19-20               19-20
        Light Catapult           3d6     1/4       1            20                    x3
        Medium Catapult      4d6      1/5       3          19-20                 x3
        Heavy Catapult         6d6      1/6       5         18-20                  x3
        Bombard                 3d10     1/6       3            20                   x3
        Fire projector            *          1/8       3           *                        -
        Light Dual Ballista     4d6     1/6        2           20                19-20
        Medium Dual Ballista 6d6     1/8        3        19-20               19-20
        Heavy Dual Ballista    8d6    1/10       5        18-20               19-20
        Accelerator               1d10*    1/1       1       19-20               19-20
*fire projector deals 6d6 fire in first round, and automatically starts a 3-die Fire
*Accelerator shot is at such speed it ignores the first 10 points of hardness
Jettisons: effect a 10x10 area on the deck of a ship
    Creatures in the area get a Reflex save to halve damage
    damage is represented by a number of hits per man-sized being
(listed number for medium, half for small, 1/4 for tiny, twice for
large, four times for huge or larger)
        -meaning that any hardness or DR is applied against each die
seperatly, making such tartgets (like ships) practically immune to this
weapon class
    Light Jettison 2xd4 R15
    Medium Jettison 3xd4 R20
    Heavy Jettison 4xd4 R25

Fire: 
When struck by fire damage a flammable vessel makes a reflex save
against the DC of the effect, or a DC equal to half the damage dealt
(for flaming arrows and the like)
on a failure, for every 10 points of damage in the initial assult 1d6 of fire is started
every crewman who can make a DC 10 strength check can douse 1d6 of fire
as a full-round action (2d6 for DC 15, 3d6 DC 20, etc.)
Create Water will douse 1d6 per two caster levels, other spells that
douse flames will extinguish a number of dice equal to that dealt to a
fire elemental by that spell.
for every 4 dice or fraction thereof at the start of the round, the fire
spreads another die unless totally extinguished [optional: make that 3
whole dice (to a minimum of one added), and every time a die rolls '1'
for its damage it goes out naturally]
the Fire! critical hit starts a 2d6 fire
One man-day of air is consumed per 2d6 per Round

Ship stats:
Size: a 1 ton or smaller vessel is always Large -1
        2 or 3 ton vessels are generally Huge -2 (unless the keel is at
least 30ft)(spherical 4 ton ships are also huge)
        a ship of keel 15 to 50ft and under 10 tons are Gargantuan -4
                so are all ships of keel and beam up to 25ft
        vessels with a keel up to 120ft and under 70 tons are Collosal -8
                as are all ships that fit in a 60ft diameter sphere
        vessels up to 300ft in keel and under 150 tons are Collosal+ -12
                or that fit into a 120ft sphere
        objects up to 700ft in keel under 700 tons are Immense (X-2, Collosal++) -16
                or up to 500ft keel under 2,000 tons
                or anything that fits in a 250ft diameter sphere
the negative number listed after each size class is it's penatly to AC
AC = 5 + size penalty + helmsman's dodge bonus if applicable + plating armour bonus
        plating/ barding adds smooth, tough material to the outer hull,
often with glacis angles, to deflect impacts.  Cost 100g times bonus
squared per ton. and reduce manueverability by one category per +3 AC or
fraction therof
(AC of ships is generally abysmal)
When making a called shot, at a weapon platform or crew member, use that
sub-target's size (and everything else) to find it's AC
    A called shot that does not touch its target checks against the
ship's overall AC at -2 to see if it made a general hit anyway

Hardness is the same as that of the constituent material: ceramic 1,
leather 2, ice/bone 3, wood 5, rock 8, iron 10, mithral 15, adamantine
20
        can add 1/5th by masterworking (Arcane, or racial specific (elves wood, leather, dwarves stone, iron))
        or double with magical augementations costing 3k (1,500gp + 750xp) per ton
Object Resistances:
    all piercing damage is halved (including balistae) --- this is why
balistae have higher damage ratings than in 2e
    damage from non-siege (large or smaller) ranged weapons is halved
    fire, electric, and acid damage is halved.  Cold damage is quartered
Sectional hp: (just for reference, if someone wants to make called shots)
    thin wood 50
    thick wood 60
    iron 100
    ceramic 50
    leather 30
    ice 50
    bone 60
    stone 150
    mithral 150
    adamantine 200
double by thickening
the force of an active Spelljamming Helm divides the hp of the ship by
5! (makes hull point damage numbers line up on wooden vessels)
a Ship breaks up when half it's sections are holed/destroyed
a Ship has one section per SJ ton
each section is a huge (-2) object for the purposes of called shots

total hp: (taken statistically, based on a triagonal grid of sections over the whole surface of the vessel)
    = tonnage * sectional hp * 1/5 (for the helm) * 1/3  for ships of at least five tons
    four tons is * 0.4 instead of 1/3rd
    three tons * 0.5
    two tons * 0.7
    one ton or less * 1
(fighter-class vessels are so small any structural damage destroys them,
so nearly all their resilliance is that of punturing the surface)
(most weapons in use will 'destroy' one section with a single hit, so
damaged sections are not a significant factor)

A hit that deals more than section hp damage after hardness and
resistance risks interior crew damage: crew in that area (randomly
dertemined) take half the weapon's rolled damage, Reflex 15 halves and
DR applies twice, from shrapnel.