Sanity checking my understanding of ships' weapons

[TheDark]

I'll lead this off with the disclaimer that none of my MegaTraveller experience has involved naval campaigns, so this is probably a bit basic of a question.
I'm trying to figure out some ship weapon layouts for personal conversion to other editions of the game. If I'm understanding correctly, ship weapons are in batteries that need to be backed through the UCP tables in the Referee's Manual to find the total number of emitters/tubes/whatever, correct? So using the Planet-class from page 83 of the Rebellion Sourcebook as an example:
Missiles are x93 with 20/10 batteries. At TL 15, only 50 ton bays are available, and they have a UCP of 9, so that's 20 50-ton batteries. Turrets are 3 tubes for 3 UCP (TL-13 turrets, since TL-21 isn't available), so it's 30 tubes split among various turrets.
Fusion guns are x04 with 5 batteries. With FG-14, you need 10 emitters for UCP 4, so there are 50 emitters.
Beam Lasers are xx7 with 3 batteries. That high of a UCP takes 15 emitters, so there are 45 total.
Particle Accelerators are 090, so also bays, but 100-ton bays this time, and there are 2 of them.
Meson guns are J0x, a single Type J spinal mount.
Sandcasters are xx7 with 15 batteries, so 150 'casters since TL-10 sandcasters are 10 launchers for UCP 7.
Repulsors are x9x. At TL-15, a UCP of 9 means 100 ton bays, of which there are 10.

So the total weapon layout of a Planet-class is probably 1 Meson spinal mount, 10 100-ton repulsor bays, 2 100-ton particle accelerators, 20 50-ton missile bays, 10 triple missile turrets, 15 triple blaser turrets, 50 triple sandcaster turrets, and 25 twin fusion turrets. Does that sound right to people with greater understanding of the system?

 

[warwizard]

Be carefull using cannon ships to understand rules, be sure to check the errata pages to see if the ship has been changed via errata. Next is to look at the tons of displacement that the installed weapons and defenses require.
Spinal mounts consume thier listed displacement.
Bays consume 1000TD per bay regardless if 50 or 100 TD bay. 32 bays = 32,000TD needed
turrets use 100 TD per turret. 100 turrets = 10,000TD needed.
I am assumming the type J meson gun needs 8,000DT
8k+32k+10K= ship must be 50KDT or larger.
Note: You picked the best selections of turrets the sandcaster and fusion batteries could have been. batteries of 10 single turrets as well for 150 single sand caster turrets, and the fusion guns could have been 50 single fusion gun turrets. That is why you also have to look at less efficient layouts they can help explain why the ship displaces 62,500DT instead of 50,000DT. (No, I did not look at the ship, just giving you some pointers.)

 

[AnotherDilbert]

So the total weapon layout of a Planet-class is probably 1 Meson spinal mount, 10 100-ton repulsor bays, 2 100-ton particle accelerators, 20 50-ton missile bays, 10 triple missile turrets, 15 triple blaser turrets, 50 triple sandcaster turrets, and 25 twin fusion turrets. Does that sound right to people with greater understanding of the system?

Yes, more or less. Turrets, not single weapons, are grouped into batteries (RM, p88), so 60 sandcaster turrets are needed. Note that a single Fusion Gun has factor 5 at TL-15, so 5 single fusion turrets are enough.

Something like this:


15 batteries of 4 turrets (60 turrets) each with 3 sandcasters are 15 batteries of factor 7.

 

[TheDark]

Yes, more or less. Turrets, not single weapons, are grouped into batteries (RM, p88), so 60 sandcaster turrets are needed. Note that a single Fusion Gun has factor 5 at TL-15, so 5 single fusion turrets are enough.

Ah, yes, I was looking at my dead tree book instead of the consolidated errata, which has a 3-point difference in UCP for all the fusion guns.

15 batteries of 4 turrets (60 turrets) each with 3 sandcasters are 15 batteries of factor 7.

I'm guessing this is an example of a case where you have to look at displacement so you know it's not 15 batteries of 5 twin turrets instead of 4 triple turrets, since both would provide factor 7 batteries? (Which basically requires rebuilding the entire ship, since system tonnages aren't provided?)

 

[AnotherDilbert]

I'm guessing this is an example of a case where you have to look at displacement so you know it's not 15 batteries of 5 twin turrets instead of 4 triple turrets, since both would provide factor 7 batteries? (Which basically requires rebuilding the entire ship, since system tonnages aren't provided?)

You don't know from the short description. I would generally assume the fewest turrets, hence the least tonnage used. Energy consuming weapons might minimise power consumption.

This ship in particular has over 200 hardpoints unallocated, so no clue there.

Five twin turrets would consume slightly more tonnage, but cost less, hence require fewer gunners, saving some tonnage. In this case it would seem that twin turrets are better, as the ship has hardpoints to spare.

 

[AnotherDilbert]

To see what is really going on you have to make a full reverse engineering of the ship:





The ship seems to be 35 000 kl overtonnage (even with the smaller crew of the errata), has a powerplant that is ~90 000 MW too large, and the mass is 50% too large. 290 hardpoints are unused.

About par for a MT ship...

 

[whartung]

Bays consume 1000TD per bay regardless if 50 or 100 TD bay. 32 bays = 32,000TD needed
turrets use 100 TD per turret. 100 turrets = 10,000TD needed.

This is badly worded.

Bays do not "consume" 1000TD, rather there is a limit of 1 bay per 1000TD. A 50 Ton bay consumes 50 tons in the ship. So, if you have a 10,000 ton ship you are limited to 10 bays. If you have 10 50 ton bays, you've only used up 500 tons of the total 10,000 available in the hull.

It's also a but more nuanced, the limits are based on tonnage available that not already allocated to other weapon systems (at least in HG).

So, if you have a 10,000 ton ship, and place a 1000 ton spinal in it, that leave 9000 tons left, which mean you can have 9 bays. If you add 9, 100 ton bays, you are left with 8100 tons of empty hull. That's enough room for 81 turrets (8100/100 = 81).

With Turrets, you can have 1 hardpoint per 100 tons, and 1 turret per hardpoint. and all turret are the same size, whether single, double, or triple, but, at least in High Guard, different weapon types require different size turrets. Energy weapons require 2 ton turrets, for example.

So, going with the above contrived example, a 1000 ton spinal, 9 100 ton bays, 81 energy turrets = 162 tons. So, 2062 tons allocated to weapons.

 

[AnotherDilbert]

So, if you have a 10,000 ton ship, and place a 1000 ton spinal in it, that leave 9000 tons left, which mean you can have 9 bays. If you add 9, 100 ton bays, you are left with 8100 tons of empty hull. That's enough room for 81 turrets (8100/100 = 81).

No, all weapons require hardpoints in MT. You are describing how LBB5'79 worked.

MT RM, p72:

 

[McPerth]

This is badly worded.

Agreed.

The wording in MT, where a ship has 1 HP per 100 dtons, and weapons consume them (1 HP/Turret, 10 HP/Bay, variable on spinals) is quite better and clearer.