OBT Forum

I just took a trip to the obt archive site : how does tonnage relate to what class ship is being viewed .

Short answer- it doesn't. 


Longer answer- One of the original Warship designs (i.e. from TR2750 the first book with warship stats) is the Vincent Corvette at 410,000 tons.  One thing you will note about the Vincent is it's huge cargo capacity.  Many years ago when Liam first started his navy project, which Takiro and I then began adding to, he made the decision that Taurian vessels were smaller then their Star League counterparts.  So a Taurian Corvette was typically between 100,000 to 200,000 tons.  Consequently the other classes tended to be lighter- a Taurian destroyer might be only 400,000 tons or so.  And so on for larger classes.  This was not a random decision but an intentional choice. 

Further adding to the confusion is that over the years (in game) weights have increased much like with real world navies today.  For example the Aegis at 750K tons was a heavy cruiser when it was introduced, in 2750 it would be a cruiser or even a light cruiser, as newer Heavy Cruisers (Luxor, Avatar and Sovetskii Soyuz) weight well over 800K tons. (You can even see where the Liberator- a rebuilt Avatar heavy cruiser was designated a cruiser given the existence of the Luxor Heavy Cruiser).  This is similar to the modern day where a WW2 Fletcher class DD was about 2500 tons, compared to a modern day Arleigh Burke which is 9000 tons.  As for the overlap in weight we even see that today with the Burkes and the Ticonderoga Cruisers which are not much bigger. 

The bottom line as Drakensis said is that in many cases we look at the role, not so much the weight when classifying ships. 

I use the following definitions when designing ships:
Battleships - heavily armored ships of the line
Battlecruiser- a faster, well armed ship intended to serve independantly, rather then as part of a battle line
Cruiser/Heavy Cruiser- depending on the fleet it is either intended to serve as the backbone of the fleet (such as the Taurian navy which has no BBs in most of my settings) or an escort for the heavier ships.  (like my Sword class cruiser for the Capellan Navy). 
Light Cruiser- I rarely use this. If I had to define it I would say a light cruiser is intended to serve as a heavy scout for the fleet. 
AA Cruiser- A cruiser outfitted with heavy anti-fighter weapons
Frigate- To me a frigate is a patrol vessel, typically it would be deployed independently.  It would have a decent cargo capacity and enough weapons to destroy lighter enemies and fast enough to out run heavier ones and get help.
Destroyer- Destroyers are jack of all trades which escort larger vessels and serve in a variety of attack and picket ship roles. They would also be used as a convoy escorts.
Corvettes- to me a corvette is a faster ship use for scouting, raiding, patrol and picket duty (yes it overlaps with the frigate)
Transport- these are ships which are mainly used to carry large numbers of troops and equipment. 

One last thought, when you look at most of the canon SLDF vessels, keep in mind that while they may be called Destroyers, Cruisers or Battleships, the vast majority are really transports and were deployed in that role. 

Hope that helps some.

while i was at the obt archive site the tonnage for the Winchester class cruiser was given as 650000 . was this for the block 1 Winchester , while tro:3057 revised , gives a tonnage for the Winchester as 740000 . is this for the FRAMed blk 1 and all blk 2 ?

The Winchester from the OBT site has nothing to do with the TRO3057R design. Back in the day before we had TRO3057R, we (liam, takiro & myself) designed many of the ships that were mentioned but not stated, such as the Pinto, Winchester, Wagon Wheel, Tharkad, Mako, Atreus, etc.  The TR3057R came out and our designs became trumped by canon.  We have done some block 2 designs, such as the refit Winchester and Dart mentioned in my FM:TC but those are based on the TR3057R designs, not our previous home designs. 

And don't worry about the rant, having been very frustrated by some of the naval aspects I understand where you are coming from.

There are varying definitions depending on the navy, which in turn depends on what role they're supposed to be taking. There's a very good essay in David Weber's House of Steel, discussing how navies are built.

To give an example, in the first Periphery Lords game a few years back, the Canopians and the Taurians both emerged as major naval powers. But comparing what each fleet called a battleship and the results were quite different. (due to technology advancing in the game well into custom rules territory, neither vessel would be legal under official rules as they stand).

The Calderon-class was a 2mt ship capable of 3g acceleration that cost the Taurians 34.5bn per hull. Primary armament was made up of 56 NAC, 60 NPL (naval pulse lasers) and 48 capital missile tubes. Secondary armament was 132 subcapital lasers and defensive armament was 144 pulse lasers and 96 AMS. To support this, the ship was fitted with 10,000 DHS, 5078 points of armour and carried a single wing of 18 fighters. There are six drop-collars and 28,671 tons of onboard cargo, with 14,000 tons of fuel.

In contrast the Warlock IIIb-class was 1.62mt, capable of 8g acceleration and cost the Canopians 14.2bn each. Primary armament was 16 N-Gauss, 12 NAC and 24 NPPCs. Secondary armament was 17 capital missile tubes and defensive armament was 75 PPCs and 120 AMS. To support this, the ship was fitted with 35,126 DHS, 4381 points of armour and carried 3 wings of 18 fighters. There were two drop-collars and 100,000 tons of onboard cargo, with 6,000 tons of fuel.

The two fleets never clashed in-game although they looked at each other uneasily. The Taurians were generally in the lead, which directly impacted the size and cost of a Canopian battleship: Warlocks had to be built fast and cheap to catch up with Taurian fleet numbers. The space left for cargo was at least in part to allow for later upgrades - the Warlock I class was out-dated before it left the drawing boards, the II and IIb both had to be retrofitted to keep up with technology...

The relative fighter strength seems to indicate the Canopians had a stronger fighter arm but actually Taurians generally used more fighters and gunboats. They, however, had dedicated carriers so battleships needed few onboard fighters. The Canopians needed the cargo space to support this and never built a warship-class of carriers.

As the faster ship, Warlocks could out-manuever Calderons (even mid-sized Taurian warships could rarely match the agility of a Warlock) but they had shorter legs, reflecting the expectation they'd be standing and fighting rather than launching offensives. This is also reflected in the larger ships having an LFB and the smaller ones lacking this. Calderons have just enough heatsinks to cover firing all weapons, whereas Warlocks were built with massive redundancy for heatsinks so that the AMS could maintain fire against the massive salvos of nuclear missiles expected to be used by a Taurian fleet.

So they're both battleships... but both built on quite different philosophies.