Converting Spelljammer Hulls into Dragonstar Starships

Converting Spelljammer Hulls into Dragonstar Starships

Version 2.0

By Robert Blezard

Update: Mark “Neo” Howe’s Custom Ship Construction Rules v.1.1 PDF file has a great table on page 8 that gives an excellent breakdown of what each Size Class’s natural AC should be. Size class and general size categories (i.e. Large through Colossal VII) match. As I become more familiar with Mark’s ship construction rules, this document will be edited to better match the work he has done. I’ve already gone through and updated my tables to reflect his Size Class table.

Figuring out Hull Points

The table on page 163 of the SFH shows the Base Hit Points for different sized vehicles. This is the best starting point used in conjunction with the Keel Length of a spelljamming vessel. The Keel Length will determine, which size category a spelljammer starship will become. FYI… here is a new table showing the maximum lengths of each size category, as listed in Mark’s PDF file. As well as on page 163 of the SFH. Mark calls this Base Length in his table.

Table 0: Maximum Lengths

Size Max. Length Size Max. Length
Large 16 ft. Colossal III 512 ft.
Huge 32 ft. Colossal IV 1,024 ft.
Gargantuan 64 ft. Colossal V 2,048 ft.
Colossal 128 ft. Colossal VI 4,096 ft.
Colossal II 256 ft. Colossal VII 8,192 ft.

As an example, a Dragonfly has a Keel Length of 100 feet, which puts it in the “Colossal” category, in size. I could also reduce the ship to a “Gargantuan” starship but I prefer to stay with what I had done previously in the 1.0 version of this document and have done my Man-o-War as a Colossal II starship.

Table 1 shows the Base Hull Points for Large through Colossal VII. The only spelljammer entry from Lorebook of the Void that even comes close to Colossal VI this is “The Spelljammer” (1,575 ft. Keel; 3,100 ft. Beam). (And I’m not going to even try to convert that without access to the Legend of Spelljammer boxed set.)

Table 1: Base Hull Points

Size Base Hull Points Size Base Hull Points
Large 70 Colossal III 400
Huge 90 Colossal IV 600
Gargantuan 100 Colossal V 800
Colossal 200 Colossal VI 1,000
Colossal II 300 Colossal VII 1,200

The numbers in Table 1 have been updated using Mark’s construction rules. This change means I will have to recalculate each Spelljammer starship’s hit point total. Oh well, split milk and all that.

Maneuver Class Adjustments (Optional)

The following adjustments modify the basic hull types (or frames) listed in the Dragonstar Starfarer’s Handbook based on a spelljammers Maneuver Class. Thus, the man-o-war, with an MC of “C”, will have a +1 bonus to handle, +2 bonus to top speed, and a +1 bonus to both acceleration and deceleration.

Table 2: Maneuver Class Adjustments (Plus Costs)

SJ Maneuver Class

Handling Adj.

Top Speed Adj.

Acc./Dec. Adj.


Cost (Cr.)


Cost (Cr.)


Cost (Cr.)


+3 +300,000/sc +6 +600,000/sc +3 +300,000/sc
B +2 +200,000/sc +4 +400,000/sc +2 +200,000/sc
C +1 +100,000/sc +2 +200,000/sc +1 +100,000/sc
D +0 +0 +0
E -1 -100,000/sc -2 -200,000/sc -1 -100,000/sc
F -2 -200.000/sc -4 -400,000/sc -2 -200.000/sc

As Mark’s ship construction rules allow for additional customization of ships, this section of my SJ conversion rules doesn’t automatically apply. Instead, these are additional bonuses added as special installs. We’ll call them Maneuver Black Box Increases. You can simply select a stand “C” option or mix and match. Some captains are willing to lose some Handling in order to get an increased Top Speed.

Armor Class/ Hull Materials

Table 3: Hull Materials

Save As Converts To
Ceramic Biological */Bio-organic
Crystal Crystal */Glassteel
Metal Mithral */Mithralsteel
Stone Adamantine */Mithralsteel
Thick Wood Steel */Titanium
Thin Wood Steel */Titanium
  • (*) Refer to page 12 of Mark’s construction rules for these alternates. His mithral and my mithralsteel are different types of hull materials.

Titanium: This is the term I chose, and that Mark also uses (great minds think alike), for the regular hull material on the starships listed in the SFH. [However, there seems to be a difference between what each of us considers it to be in regards to standard AC bonuses (see below).] Close observation shows that vehicles and starships have the same Natural AC Bonus at the same Size Category (in most cases). Only the hovertank break this rule and has a +10 natural AC bonus.

Table 4: Natural AC Bonuses


Natural Bonus

to AC


Natural Bonus

to AC

Large +5 Colossal III +10
Huge +5 Colossal IV +30
Gargantuan +5 Colossal V +60
Colossal +6 Colossal VI +80
Colossal II +6 Colossal VII +100

I checked the Armor Bonuses to AC for the vehicles and starships, as well, but they aren’t as consistent. Large, Huge, and Gargantuan vehicle/starship armor bonuses tend to range all over. Here are the Armor Bonuses to AC for each of the standard spacecraft. Explorer: +3; Free Trader: n/a/; Freighter: n/a; Interceptor: +3; Corvette: +3; Destroyer: +5; Cruiser: +10; Carrier: +15; Battleship: +20; Dreadnaught: +40.

Noting Mark’s construction rules, I’ve decided to rework the following table:

Table 5: Standard Armor Upgrades (Titanium)


Armor Upgrade


Armor Upgrade
Upg Bonus Cost (Cr.) Upg Bonus Cost (Cr.)
Large See below See below Colossal III +10 6 Million
Huge See below See below Colossal IV +20 14 Million
Gargantuan See below See below Colossal V +40 32 Million
Colossal +3 1.2 Million Colossal VI +80 72 Million
Colossal II +5 2.5 Million Colossal VII +160 160 Million

Creating realistic numbers for the first three size categories is a numbers game. If you feel the need to have a standard upgrade value then I suggest sticking with a range of +3 to +10 depending on the type of vehicle being considered for conversion.

For example, the Strike Aircraft (pg. 165) has an Armor Bonus of +5, while the Interceptor (pg. 169-170) has an Armor Bonus of only +3. Both are Gargantuan and both are flight-type vehicles that need to be fast and somewhat sturdy. If converting a spelljamming vessel that is the same size category then an Armor Bonus of +3 to +5 would be standard.

For the larger spacecraft I have simply ignored the Carrier amount as an anomaly and doubled the armor values incrementally from +5 (Colossal II) to +160 (Colossal VII).

For more details, on the other types of hull material I have created and use, see my document. (Some of that is still a work in progress and needs to be modified to better reflect Mark’s construction rules regarding hull materials. Also see page 46 of Mark’s construction rules for details on Increased Armor.)

Cost Calculation

The cost of converted Spelljammers are changed based on what is in Mark’s Ship Construction Rules PDF file. No more having to strip the standard spacecraft and then rebuild.

Below are the standard costs in credits for the different Size Classes.

Table 8: Size Class Base Costs

Size Class Standard Cost (Cr.) Size Class Standard Cost (Cr.)
Fighter 1 Million Cruiser 105 Million
Shuttle 2 Million Battleship/Carrier 260 Million
Explorer/Free Trader 10 Million Dreadnaught 540 Million
Corvette/Freighter 28 Million Leviathan 860 Million
Destroyer 55 Million Space Station 1.4 Billion

However, Mark’s rules are a little more complex than what I was doing previously so there are more steps to calculating what my standard SJ converted starships will cost. My Man-o-War cost calculation will have to be completely redone, as will those I’ve posted on my Arcanum of the Stars yahoo group. It should be fun.