Pinnaces for the ANNIC NOVA

[Timerover51]

I was looking at the ANNIC NOVA adventure, both in JTAS No. 1 and in the Double Adventure book, working out how to put it into My Heretical Traveller Universe. I was looking at the pinnaces, trying to figure out how much room for drives was in them, so I got out my calculator and compass and did some measuring and number crunching. They are essentially cylinders of 4.5 meter diameter, based on the deck plans. That means that for every meter in length, they have a volume of 15.9 cubic meters, or 1.136 dTons per meter of length. They are rated at 40 dTons, so when you divide 40 dTons by 1.136 you get a length of 35.2 meters. Then, by dividing 35.2 by 1.5 meters, the standard deck plan square, I get 23.46 deck plan square in length, in theory.

When I started counting deck plan squares from forward to aft in the Double Adventure, I got 16, in the magazine article, 17. So the deck plans are about 50% percent short. When I add that additional room, all sorts of space for maneuver drives is available. From looking at the drive tables in Starter Traveller, it looks like a 5G Maneuver Drive for a 40 dTon hull should equate to a 2G Drive for a 100 dTon hull, so 1 dTon for the Maneuver Drive and 4 dTons for the Power Plant add up to 5 dTons, so only take up 4 meters of length, call it 3 deck squares. Put the contra-gravity field generators under the deck with the field plates on the outside of the hull, add some storage space under the deck for supplies and small package cargo, allow for maybe another deck square in length for life support, and you have still have 20 deck square to play with, but allowing for 2 deck squares for the bridge, you have 18.

Converting all of this into feet, and then looking at cargo plane volume in my FM101-10 from 1959, does get quite interesting. A deck plan square is 1.5 meters or almost exactly 5 feet, 59.05 inches to be precise. That makes the pinnace 15 feet in diameter, and 115.5 feet long, which is about the size of a passenger jet fuselage. The cargo compartment on the C-97 Stratofreighter, a cargo version of the commercial Boeing Stratocruiser, is 63 feet 8 inches long, 105.5 inches wide maximum with an 87 inch minimum, and a height of 96 inches maximum with an 87 inch minimum. I chose the C-97 as it has a circular fuselage. Eighteen deck squares converted into feet are, if you wish to be precise, 88.5 feet long, while 3 deck square wide convert to 14.75 feet or 177 inches. If the deck is exactly in the center of the cylinder, you would have 88.5 inches clearance in the center. Basically, I have more cargo volume, quite a bit more, than a C-97. Maybe for the next post I will list what a C-97 could carry. The allowable cargo load for the C-97 was 46,000 pounds or 20.86 metric tons.

Edit Note: I forgot to include the lower cargo compartments on the C-97.

Lower cargo compartments, two each: 264 in. long, 74 in.wide, and 60 in. high.

Those would be 22 feet long, so 44 feet total, but a lot less wide that would be available on the pinnace. The pinnace might have close to the same clear. As I said, all sorts of cargo space.

 

[Swiftbrook]

scratch that

 

[Timerover51]

I checked my FM55-15, Transportation Reference Data, December 1963, and the maximum load for a C-97 is 68,000 pounds or 30.8 metric tons. So the 40 dTon pinnace should be able to load 30 metric tons of cargo in the cargo version. That should cut into the 5G acceleration however, unless the 5G is in loaded condition. If that is the case, and assuming that the pinnace masses about 40 tons, then the acceleration in light condition should close to double.

 

[Hyphen]

You can also take a look at Winchell Chung's 3D update to his original pencil-and-paper design:
http://spaceart1.ning.com/photo/albums/annic-nova

Deckplans are on pg 2 (sadly, not of the pinnaces):
https://www.flickr.com/photos/nyrath/sets/72157626769746781/with/7489511316/

The green pic on his Deviant Art page has a grid which *may* (?) help with measurements:
http://nyrathwiz.deviantart.com/gallery/43345509/ANNIC-NOVA

 

[Timerover51]

Thanks for the links. I am working on a sister ship, the ANNIC FALCON.

 

[GypsyComet]

I checked my FM55-15, Transportation Reference Data, December 1963, and the maximum load for a C-97 is 68,000 pounds or 30.8 metric tons. So the 40 dTon pinnace should be able to load 30 metric tons of cargo in the cargo version. That should cut into the 5G acceleration however, unless the 5G is in loaded condition. If that is the case, and assuming that the pinnace masses about 40 tons, then the acceleration in light condition should close to double.

In the editions that care about mass, ships without significant armor run about 4 to 8 metric tons per displacement ton empty, with the average changing based on cargo capacity and drive ratings. While the Pinnace isn't in the TNE core book, the Ship's Boat and Cutter are, and both weigh in at around 10 metric tons per dton due to the drives. They'll still float in water right up to 14 metric tons per dton or so. TNE in particular required a recalculation of rated thrust if the mass per dton got above 15 tons.

So the Pinnaces are, under those assumptions, rated for 5Gs with any but a really dense cargo load. If you consider them to weigh 400 tons, then the equivalent thrust would be 2000 tons of thrust each. The statement in DA1 that one can push the Annic Nova around at 0.1G suggests that the AN weighs in at around 20,000 metric tons. That is rather heavy for a ship stated to be 600 dtons, especially when a big chunk of that volume is the very low density Collector. Something closer to TNE reality would be around 6,000 metric tons or less, suggesting that a Pinnace can actually push the AN around at 0.3 to 0.4G under ideal conditions. I'm willing to accept that the maneuver dock is not ideal, however, allowing the 0.1G figure to be used guilt free.

(EDIT: corrected my numbers and conclusions)

 

[Timerover51]

In the editions that care about mass, ships without significant armor run about 4 to 8 metric tons per displacement ton empty, with the average changing based on cargo capacity and drive ratings. While the Pinnace isn't in the TNE core book, the Ship's Boat and Cutter are, and both weigh in at around 10 metric tons per dton due to the drives. They'll still float in water right up to 14 metric tons per dton or so. TNE in particular required a recalculation of rated thrust if the mass per dton got above 15 tons.

So the Pinnaces are, under those assumptions, rated for 5Gs with any but a really dense cargo load. If you consider them to weigh 400 tons, then the equivalent thrust would be 2000 tons of thrust each. The statement in DA1 that one can push the Annic Nova around at 0.1G suggests that the AN weighs in at around 20,000 metric tons. That is rather heavy for a ship stated to be 600 dtons, especially when a big chunk of that volume is the very low density Collector. Something closer to TNE reality would be around 6,000 metric tons or less, suggesting that a Pinnace can actually push the AN around at 0.3 to 0.4G under ideal conditions. I'm willing to accept that the maneuver dock is not ideal, however, allowing the 0.1G figure to be used guilt free.

(EDIT: corrected my numbers and conclusions)

FOUR HUNDRED TONS for a 40 dTon Pinnace!!!!!! I assume based on your quoted figures that you are not kidding. What are they making these out of: Lead, Osmium, Iridium? Whoever came up with those figures did not know anything of naval architecture or aircraft structure. They simply through some figures together and called it "RULES".

Another reason for using the C-97 is that its fuselage is about the same length as the Pinnace, at 110.5 feet/33.7 meters to the PInnace at 115.5 feet/35.2 meters. Total weight of the C-97 empty, including 141 foot wings, landing gear, horizontal and vertical tail stabilizers, and four big and heavy Pratt & Whitney R-4360 engines is about 82.500 pounds or 37.4 metric tons. The fuselage was pressurized and the aircraft was cleared for operation to 35,000 feet, so had to handle a reasonable pressure differential between the inside and the outside.

Now treating the Pinnace as a cylinder, which it practically is, with the given length and diameter, I get 497.6 square meters for the cylinder sides, and 15.9 square meters for each end, so call it a surface area of 530 square meters. A square meter is equal to 10.76 square feet, and a half-inch thickness of steel plate weighs 20 pounds per square foot. Crunching the numbers gives me a hull weight of 50.9 long tons. However, the dimensions of the pinnace would make a nice sub hull, and if made of half-inch HY-80 steel plate, it would be good down to at least 200 feet or so, and if using HY-130 steel, more like 300. The pinnace is not going to have to handle a pressure differential of 75 pounds between the interior and exterior, so can be made of lighter plating, and including the insulation needed between the exterior plating and interior, interior plating, and the framing, I would figure the hull weight of the Pinnace at somewhere between 20 and 25 long tons, or 20.3 and 25.4 metric tons.

Cross-referencing that with one of my rules-of-thumb for water-borne vessels, 40 Traveller dTons equates to 200 gross register tons, that a break-bulk cargo ship would go about 45% of the gross register tons, that would put the mass of the Pinnace at 90 tons. However, the Pinnace is more of a tube, like a bulk carrier, so could go as low are 16% of gross register tonnage, or 32 tons. That feels too light, but the craft is not going to have to face a winter gale in the North Atlantic, so can be lighter than 90 tons. Based on my computation for hull weight, and the total weight of the C-97, a mass of around 40 to 50 tons seems about right. That would allow for about 20 to 30 tons of mass for drives, power plant, life support, and some light internal structure. Oh, and if you say that the drives and everything are a lot heavier than 20 to 30 tons, then you have a pinnace that may float, but because of these nasty things called center of gravity and center of buoyancy, it will look like a pencil sticking up out of the water vertically.

As for your figures for mass compared to Traveller dTons, I figured out the mass of the Azhanti High Lightning-class ships, based on the information given in the AHL game for the Haunting Thunder scenario. My analysis on that is already 3 pages long, so to make it short, the mass of the AHL comes out at 98,000 tons for a 60,000 Traveller dTon ship. That makes for 1.63 mass tons per Traveller dTon. That would also make it 0.3267 mass tons per gross register ton, so more than a little light in terms of structural weight for a water-borne ship of the stated dimensions, especially as it is supposed to be a warship.

 

[GypsyComet]

FOUR HUNDRED TONS for a 40 dTon Pinnace!!!!!! I assume based on your quoted figures that you are not kidding. What are they making these out of: Lead, Osmium, Iridium? Whoever came up with those figures did not know anything of naval architecture or aircraft structure. They simply through some figures together and called it "RULES".

Cast aspersions aside (you'd need to talk to the architects of TNE), these are space-rated vehicles that are not particularly worried about aerodynamic lift but may have to enter a variety of hazardous atmospheres, including the possibility of being strapped to the outside of a ship during jump. They are sheathed in multiple centimeters of steel or heavier, not 6mm aircraft aluminum. That said, the Pinnace is likely getting most of that weight from its powerplant. That 5G rating needs a lot of power, and fusion plants run, since CT's Striker, about the density of water as an average (steel and tougher in some places, vacuum in others). That's 14 metric tons per dton.

By comparison, the typical Far Trader is a lot less dense when empty. Without cargo it comes in at a little over five metric tons per dton.

 

[Timerover51]

Cast aspersions aside (you'd need to talk to the architects of TNE), these are space-rated vehicles that are not particularly worried about aerodynamic lift but may have to enter a variety of hazardous atmospheres, including the possibility of being strapped to the outside of a ship during jump. They are sheathed in multiple centimeters of steel or heavier, not 6mm aircraft aluminum. That said, the Pinnace is likely getting most of that weight from its powerplant. That 5G rating needs a lot of power, and fusion plants run, since CT's Striker, about the density of water as an average (steel and tougher in some places, vacuum in others). That's 14 metric tons per dton.

By comparison, the typical Far Trader is a lot less dense when empty. Without cargo it comes in at a little over five metric tons per dton.

My initial hull calculation was based on 12.7mm steel plate, not 6mm Aluminum, and before claiming how tough jump space is, I suggest that you look at the G-loading for ships operating in the North Atlantic in the winter.

Why in heaven are they using multiple centimeters of steel? Give me a sound reason for that. As for fusion plants being heavy, the fusion plant on the 4 ton air raft is capable of supplying sufficient power to put the air raft in orbit. How much does that weigh?

Concerning CT Striker, I will not make any comments on that. I do have it.

Also, I notice that you did not address the mass of the Azhanti High Lightning class. The rules for the game specifically state that the ship is insufficiently strong to ever be landed, even on an airless planets. Based on that, the ship is unable to support its mass even when on a Size 1 planet. If the ship was constructed of multiple centimeters of steel, that would not be the case. Yet is it rated at Jump-5. Based on that, the rigors of Jump Space do not require that structurally strong a ship.

The following is part of a write up I did on analyzing the Paul A. Tregurtha, currently the largest bulk carrier on the Great Lakes compared to building it to Mongoose water-going ship rules. The Tregurtha has no problems whatsoever supporting its empty weight while in dry dock. If you check on the boatnerd.com Great Lakes Seaway site, I believe you can see photos of her in dry dock. I am not sure I would take her through a bad November gale on the Great Lakes, but she will handle anything short of that.

The dimensions of the ship are as follows, in both English and Metric. The length is 1,013 feet 6 inches or 308.91 meters, beam is 105 feet even or 32.00 meters, depth of main hull body (this is not draft but the depth from the keel plating to the top of the highest continuous deck, so does not include the aft superstructure) 56 feet even or 17.07 meters, loaded draft with 68,000 tons (long tons of 2240 pounds) or 69,092 metric tons of iron ore pellets is 30 feet 1 inch or 9.17 meters, and a light displacement, i.e. empty ship, of 14,497 tons (again long tons of 2240 pounds) or 14,730 metric tons, which would be the empty weight or mass of the ship.

The total volume of the main hull, not including after superstructure is about 169,000 cubic meters, or 12,072 Traveller dTons, Light ship weight is 14,730 metric tons, and she can carry a load of 69,000 metric tons of taconite pellets (iron ore). By the way, that light ship mass includes a pair of Diesel engines supplying 16,080 brake horsepower and a 1500 horsepower bow thruster, so the mass is not all hull weight. Mass per Traveller dTon is 1.22 metric tons. The dimensions of the Azhanti High Lightning are given in the game as:

405 meters long by 61.2 meters wide by 36.4 meters high.

That make the AHL-class about a 100 meters longer than the Paul A. Tregurtha, with twice the beam and twice the hull depth. If the AHL-class were built out of your

multiple centimeters of steel or heavier

,

they should have no problems whatsoever landing on any size of airless planet. According to the description in the game rules, an AHL-class ship can never land anywhere.

I will stick with my 40 to 50 tons mass for the Pinnace.

 

[GypsyComet]

I will stick with my 40 to 50 tons mass for the Pinnace.

Have fun, then.

 

[Timerover51]

I forgot to add that if you make the hull of the Pinnace out of 1 inch/2.5 centimeter steel plate, the weight of the hull does go up to 101.8 long tons or 103.43 metric tons. I used Maneuver Drive A and Power Plant A for the drive plant of the Pinnace, so if I use your figure of 14 metric tons per dTon for power plant and also for the maneuver drive plant, as they occupy a total of 5 dTons, that would add 70 tons to the mass of the Pinnace. That would bring the mass of the Pinnace up to 173 metric tons or so, a far cry from the 400 tons mass that you are quoting.

Now, in by the end of World War 2, US subs were being built of seven-eighths inch vanadium alloy steel plate, 2.22 centimeters, and were rated at a safe diving depth of 450 feet, with a crush depth of 900 feet. The vanadium alloy was equal to HY-65 steel. They could survive a standard 350 pound depth charge inside of 25 feet. (Yes, I have the exact distance in my declassified WW2 files, but it is still theoretically classified). An half-inch of HY-130 plating would be stronger than seven-eighths of an inch of HY-65 plating. Are you claiming that Jump Space is rougher than a 350 pound depth charge at 25 feet, or worse than a pressure differential of 385 pounds per square inch?

Also, you have the 200 ton Far Trader at a mass of 5 metric tons per dton. That would give a mass of 1000 tons. The Pinnace has a mass of 400 metric tons per your quote, and gives 5G acceleration. Put the Pinnace Drive A in the 200 ton Far Trader, and you have 2G acceleration, not 1G as per the rules. Something is not adding up in the figures from the rules you are citing.

 

[GypsyComet]

That would bring the mass of the Pinnace up to 173 metric tons or so, a far cry from the 400 tons mass that you are quoting.

I made it clear that I was estimating the Pinnace based on the Ship's Boat and Cutter from the TNE main rulebook.

You have played the "this game is stupid for not matching the real world" card, which means your topic has lost my interest.

 

[Timerover51]

I made it clear that I was estimating the Pinnace based on the Ship's Boat and Cutter from the TNE main rulebook.

You have played the "this game is stupid for not matching the real world" card, which means your topic has lost my interest.

I concede that I should have used the word, "estimating", rather than "quoting". My apologies. As for matching the real world, in theory, Real World physics still sort of apply in Traveller, and I do not recall saying that the game is "stupid". There are some massive inconsistencies in the game, however, which is why DonM keeps busy with errata.

One massive case in point is the whole Haunting Thunder scenario in the Azhanti High Lightning game. In the ship description, the following statement is made.

The ships, constructed using an outer frame system, were unable to withstand the uneven stresses of gravity at a surface were they ever to land, even on an airless world. From Page 2, Supplement 5, Lightning Class Cruisers.

The Haunting Lightning scenario has the ship down, INTACT, on as liquid surface of a Gas Giant, with the ship flooded with liquid ammonia from decks 70 to 84, which are at the stern. Presumably, the ship is floating vertically, nose up, stern down, based on the description in the scenario. The 15 decks comprise, at 4.5 meters deck height, again per the ship description, one-sixth of the volume of the ship, which works out to be displacing 98,000 tons of liquid ammonia. The forward gooseneck is reported to be gone, so the ship may mass a little more than 98,000 tons.

Would anyone care to try and reconcile the statement from Supplement 5 with the game scenario?

 

[Hyphen]

Dear Folks -

Hi! The only bit of info I can inject in this discussion are the MT weights for these ships.

I know, this is a TNE discussion, but it's still filed under "General" rather than the TNE-specific thread. Besides, I can't see the AHL given the TNE treatment, apart from maybe appearing in the Battle Rider ruleset. And since each Trav version is derivative of the previous - even if not directly compatable - at least you'll have a ball-park figure to argue against.

Here are those stats (taken from Arrival Vengeance):

Azhanti High Lightning-class Frontier Cruiser
Disp=60,000, Unloaded=717,229, Loaded=775,596, Cargo=400 tons, Fuel=28,358 tons

Note: Unloaded - Loaded = 58367 metric tons = 28358 tons of fuel + 60 fighters, 4 fuel shuttles, 6 gunboats

Rampart light fighter
Disp=10, Unloaded=4.6, Loaded=18.7, Cargo=6.75kl, Fuel=33.6kl

Fuel Shuttle, Disp=400, Unloaded=2248, Loaded=4069.6, Fuel=4500kl

No stats for the gunboats.

Unless noted, weights are in metric tons. ;-)

 

[elbmc1969]

The Haunting Lightning scenario has the ship down, INTACT, on as liquid surface of a Gas Giant, with the ship flooded with liquid ammonia from decks 70 to 84, which are at the stern. Presumably, the ship is floating vertically, nose up, stern down, based on the description in the scenario. The 15 decks comprise, at 4.5 meters deck height, again per the ship description, one-sixth of the volume of the ship, which works out to be displacing 98,000 tons of liquid ammonia. The forward gooseneck is reported to be gone, so the ship may mass a little more than 98,000 tons.

Would anyone care to try and reconcile the statement from Supplement 5 with the game scenario?

Umm, 'cause ships are designed for thrust along the long axis?

In the case of the AHL, it has no landing skids and there are no hard pads on the hull to support it on the surface of a world. It has no contragravity. It's not designed to support its own weight on a planetary surface. This would be like putting your car on the lift at the garage by randomly placing the lift pad on the underbody. The car won't simply fall apart, but you're almost certain to suffer local damage, and it may be effectively fatal, say by rupturing the fuel tank or putting enough weight on the drive shaft or a CV joint that something snaps in a very bad way.

It might be able to sit on its tail on a solid planet, except that it would almost certainly fall over ...

 

[elbmc1969]

Another reason for using the C-97 is that its fuselage is about the same length as the Pinnace, at 110.5 feet/33.7 meters to the PInnace at 115.5 feet/35.2 meters. Total weight of the C-97 empty, including 141 foot wings, landing gear, horizontal and vertical tail stabilizers, and four big and heavy Pratt & Whitney R-4360 engines is about 82.500 pounds or 37.4 metric tons. The fuselage was pressurized and the aircraft was cleared for operation to 35,000 feet, so had to handle a reasonable pressure differential between the inside and the outside.

I'm not going to argue that everything in the Traveller ship building rules makes perfect sense, but ...

The C-97 is primarily weight-limited. You can load the pinnace chock-full with lead and it will still fly ... That alone argues for much greater structural strength.

The C-97 was g-limited to about 3Gs for turning with the wings. At full load, a 3G turn would have a pretty good chance of snapping the wings off ... The pinnace is rated to 5Gs. Of course, the much higher tech should allow a much lighter structure!

C-97 takeoff run is 6-7000 feet at 150,000 lbs and takeoff speed is around 110 KTAS. That's about 1829 m and 57 m/s. Working backwards to d=0.5at^2, where V(t)=at, V(t)=57m/s, so 1829m=0.5*57m/s*t, which means that 64s=t. Just over a minute for the takeoff roll, so a=0.9m/s, ~0.1G acceleration. Assuming purely linear thrust numbers, if you wanted to achieve 5G acceleration, you'd need 50 times as many engines.

Each of the P&Ws weighs about 3,800 lbs., the four weigh around 15200 lbs. 49 more sets will add 744,4800 lbs to the weight of the aircraft (~3700 tons), which will obviously require a lot more structure just to support the weight. Of course, the structure needs to be able to withstand the acceleration as well.

I guess I'd also try throwing out the excuse that the pinnace can make multiple hypersonic launches and reentries per day with minimal maintenance, which is pretty freaking impressive. People just don't realize how fast you have to go to get down to the surface in any reasonable length of time, or how much stress there is involved. Given buffeting and such, the pinnace needs to be stressed not only for 5G longitudinal acceleration, but also for extreme lateral acceleration. For example, an aerodynamically unbalanced ballistic missile can perform a 30G barrel roll during reentry ... that's pretty nasty on an empty airframe. A heavily loaded airframe won't accelerate nearly as fast, but the force on the vehicle will be the same. The missiles tend to break up under these circumstances, so you probably want the pinnace to be able to survive the same force, which means building it to survive 50% over-G.

The gravitic compensators probably aren't strong enough ... another flaw if FF&S

At a certain point, we have to grin, say, "It's a game," and realize that, as GMs, we can just stat things out however we want to fit the needs of the game, etc.

 

[Timerover51]

I am not sure why the Pinnace would be doing hypersonic launches and re-entries on a daily basis. In my Traveller Universe, any ship entering atmosphere first kills their orbital velocity in vacuum, and retains altitude using their contra-gravity lifters. They maintain just enough speed to retain position over the landing location on the planet, and let down using the contra-grav field. They may do some atmosphere travel if needed, but not at hypersonic speeds. Upon lift-off, that is done with the contra-grav lifters, and while they may pick up some speed in atmosphere, they hold off on maximum acceleration until pretty much in vacuum.

Your post does raise the question of how does a Pinnace maneuver, not just in the atmosphere but in vacuum, as your drive is aligned with the long axis of the craft. Have to give that some thought. I am assuming something on the order of the Dean Drive or reactionless thrusters for a drive plant, so do you slightly angle the axis of the drive beam, or do you have small reactionless thruster plates or micro-drives at the front and rear of the craft to change attitude? I do not see the Pinnace as pulling any High-G maneuvers in the atmosphere.

I am not sure about that 5G drive, as at full thrust/power, in about 10 minutes, you are moving at 20 miles per second, which is way over escape velocity for Earth.

Edit Note: Using this technique, I have no problems landing a Broadsword-Class mercenary cruiser on a planet with a Standard to Dense Atmosphere.

 

[elbmc1969]

Your post does raise the question of how does a Pinnace maneuver, not just in the atmosphere but in vacuum, as your drive is aligned with the long axis of the craft. Have to give that some thought. I am assuming something on the order of the Dean Drive or reactionless thrusters for a drive plant, so do you slightly angle the axis of the drive beam, or do you have small reactionless thruster plates or micro-drives at the front and rear of the craft to change attitude? I do not see the Pinnace as pulling any High-G maneuvers in the atmosphere.

Angling the drive sucks. You'll get 90%+ of your thrust forward, so small maneuvers are an intense pain in the ass.

Any vector ship has attitude controls. If you haven't fooled around with actual vector movement, do so and you'll see why.

 

[Timerover51]

Angling the drive sucks. You'll get 90%+ of your thrust forward, so small maneuvers are an intense pain in the ass.

Any vector ship has attitude controls. If you haven't fooled around with actual vector movement, do so and you'll see why.

Yes, I have done vector movement, since about 1972.