After re-reading the rules, I'd say the latter. The Extra Hull Damage language seems to suggest that the extra hull hit is in addition to any damage roll results, and thus is separate in my mind.

Each damage die would automatically inflict an extra hull hit, then you would roll for damage and double all those results.

20 hull, then roll 10 dice for damage, doubling the effect of each die.

Perhaps... but it's also consistent with the math.

Extra Hull Damage = x3 (because it takes an average of two additional points of damage to get an additional hull hit)
Double Damage = x2 (for obvious reasons)

A weapon with both these traits that inflicts 10 damage dice would result in an average of 30 hull hits; without these traits, the average is 5 hull hits. Thus, the two traits combined increase effectiveness by a factor of 6 (2 x 3).

You don't need that weapon. Just a simple 1/1/1, EHD, Double Damage, Catastrophic weapon. Now that would be scary as hell. Space would be prohibitive, but as we're talking about massively impractical weapons...:)

Heh, looks like someone is trying to do Hydrans...

I've built BFG-equipped ships but have never gone to that extreme.  Double Damage is sooo much fun.    Also, I prefer two smaller but similar weapons as I will miss with one shot, almost always. 

95% chance to hit?  That means I have a 50% chance to miss.  Believe me, that's how my dice math works.

I see such a weapon as similar to spinal mounts from the Traveller RPG ship design rules.

(1500)

Hull: 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1   
Engines: 6 6 6 6 6 5 5 5 5 4 4 4 4 3 3 3 3 3 2 2 2 2 1 1 1 1   
Screens: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0   
Weapons: 1:X 2:X 3:X 4:X 5:X 6:X

X: "Soul Lance"  10/20/30, 3/2+/1/1
Inv. Range-Based ROF; Piercing +1; Minimum Range
[AB][AB][AB][AB][AB][AB][AB][AB][AB][AB][G][G][G][G][G][G][G][G][G][G][G][G]

Special: Hyperdrive; Stealth; Anti-Fighter Batteries; Cargo (200)

This murders smaller ships, each one of its guns firing 9 times at long range. A grand total of 198 shots fired at little ships.

And by tech zero, that means all techs are zero, not the sum total of +'s and -'s;  so no -2 to Fighter tech and +2 to Weapon tech cheesiness.

I'm amazed that you guys haven't set up some "fleet restrictions" and tried some games that way.   One of the ideas for "fleet restrictions"is that each player gets to pick 2 weapon effects and 3 special abilities and one weapon effect for each other player.  So if you have 4 players, you get to pick two of your weapon effects and your opponents get to pick the other 3. 

The other idea is to build a fleet and then before the games, bid (in VP) for which fleet that you get to use.  The last player to get a fleet is awarded a 20% bonus in VP for taking the last fleet available.  Might be a nice change from your normal fleets.

-Bren

HELL YEAH

Maybe in a campaign game where each player controls a species/interstellar government, but for one-off scenarios... nah.

Then what would be the point of designing ships that I want to play?