Errata

Interstellar Wars says that 50-dton bay weapons displace 8 turret hardpoints and 100-dton bay weapons displace 10 turret hardpoints.

The problem with this is both the sample ships they give have negative hardpoints remaining when you're done.  -4 for both Kargash and Indomitable.

It appears that it was 6 hardpoints for the 50-dton and 8 hardpoints for the 100-dton in the playtest and someone forgot to update the sample ships.

I've made note of it.

I also remember when SJ Games kept up on the errata.

Figuring out how many turrets you could have was a lot simpler in LBB Traveller.

You got 1 turret hardpoint for every 100 dtons.  You got 1 bay slot for every 1,000 dtons, and this 1,000 doesn't count towards turrets.  You get 1 major weapon mount, period, and its dtonnage is subtracted from the hull tonnage for turret/bay slots.

So LBB Indomitable would have 25,000 dtons left over for bays and turrets once the 5,000 dton spinal A-meson gun was subtracted.  That leaves space for 25 bays or 250 turrets.  The 5 bays take off another 5,000 of allocation leaving "just" 200 turret hardpoints.

GT: Interstellar Wars uses a surface area calculation to figure out how many hardpoints you get and has a listing for how many are consumed by bay and major weapons.

She starts with 87.  The spinal meson gun uses 40, the repulsor and two fusion gun bays are supposed to use 10 each and the two light missile arrays 8 each; leaving just 1 hardpoint for the 5 heavy turrets and their 10 fusion guns.  Ooops!