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CT Only: Supplement 7 Express Boat Tender

Howdy Patron Zero,

That's the basis for my upcoming attempt to rework the classic tender design as a more rough compound hull than the neat smooth package such appears.

Also my take on tenders, in particular those supporting the express boat network and the ships of the Imperial Interstellar Scout Service, are more a hybrid of tow-truck and mobile dry-dock facility.

Actually the tender is a tow truck, mobile gas station with a garage, post office, and a truck stop with a couple of bunks and showers for the pilot passing through.
 
That's the basis for my upcoming attempt to rework the classic tender design as a more rough compound hull than the neat smooth package such appears.

Also my take on tenders, in particular those supporting the express boat network and the ships of the Imperial Interstellar Scout Service, are more a hybrid of tow-truck and mobile dry-dock facility.
Since I flatly refuse to believe in X-boats that don't have maneuver drives1, X-boat tenders IMTU aren't meant for towing (though since they have maneuver drives, they can be used for such purpose in an emergency).
1 And I really, really wish Marc Miller would bite the bullet and retcon those silly things out of existence.


Hans
 
Howdy Hans Rancke,

Since I flatly refuse to believe in X-boats that don't have maneuver drives1, X-boat tenders IMTU aren't meant for towing (though since they have maneuver drives, they can be used for such purpose in an emergency).
1 And I really, really wish Marc Miller would bite the bullet and retcon those silly things out of existence.
Hans

You are correct that the x-boat tender does not physically tow an x-boat, however securing the boat in the ship/vehicle bay is similar to the tow trucks that have flat beds to load vehicles on and transport them to the owner's requested location.

Per the x-boat background material the custom jump drive provides approximately three days of life support after the ship drops out of jump space.

I'm really glad that I didn't know about the approximately 3 days of life support and that none of my characters where X-boat pilots. With my luck the character would have died an hour before the tender got to me.

Yep, another reason that the x-boat should be redesigned but not out of existence.
 
XT Navigation lights

Evening all,

On the last file I included navigation lights as part of the deck plan. After the file was uploaded I went back and did a drawing showing the lights. Of course my limited skills at drawing the side views of the hull looks like squares of varying lengths, are missing the bay window and the mobile turrets.

I don't want to take up anymore file space but I am willing to email the PDF to anyone interested.
 
... I'm trying to keep the same design and changed the length and redrawing the deck plans. ...

Oh, dude, you are brave.

You can revise the size and deck plans - but it is a daunting task to design it to take on four x-boats (which are about the worst possible shape for storing in what amounts to an oval box) and meet the other criteria.

My best effort stacks the four x-boats in a 39 meter long, 12 meter tall, 24 meter wide oval tube while eliminating that left-hand section with the elevator and the hallway, and it still comes out with 760 dTons for the boat bay. Personally, I like it: I moved the bridge/quarter deck aft between the boat bay and the fuel/engine decks, so that I didn't need that elevator to communicate between fore and aft. I switched from the canon H drives to E drives, which Book 2 says are adequate and which gave me some tonnage to work with. I lost the cargo bay, the extra tonnage I'd gotten off the drives, and most of my extra fuel in the effort to be able hold the 4 xboats, but it's long enough and wide enough to stack four x-boats and two scouts. I get 4 57 dTon decks aft of the boat bay: a 55 dTon engine deck with a couple dTons for fuel, a 57 dTon quarters deck with part of the bridge, and two 57 dTon fuel decks (with a half dTon cut out of each for an elevator through them from the engines to the quarters). It's 12 dTons shy of target, so a 12 dT bridge extension juts out below, just behind the boat bay doors. I get 115 dTons fuel, which serves the ship with only 5 dTon to spare; tempted to convert that to cargo. I don't have any other ideas.

If I had been designing this thing from scratch, I'd have designed the tender first then designed x-boats to suit my tender.
 
If I had been designing this thing from scratch, I'd have designed the tender first then designed x-boats to suit my tender.
There's no need to do that. Just put the X-boats in cone-shaped bays with domed hatches. That carries them at 100% of tonnage (or 105% if we follow another ship design system, as I would prefer). You do need to be able to utilize the space in between, and if you don't want to use if for fuel tonnage, you might have some waste space. Nowhere near double up, though.


Hans
 
There's no need to do that. Just put the X-boats in cone-shaped bays with domed hatches. That carries them at 100% of tonnage (or 105% if we follow another ship design system, as I would prefer). You do need to be able to utilize the space in between, and if you don't want to use if for fuel tonnage, you might have some waste space. Nowhere near double up, though.


Hans

That's fine if it's only an x-boat tender, but the bit about accepting x-boats or scout/couriers seemed to suggest it needed be dual-use. I could see the thing being sent out to bring home the occasional broken down scout.
 
That's fine if it's only an x-boat tender, but the bit about accepting x-boats or scout/couriers seemed to suggest it needed be dual-use. I could see the thing being sent out to bring home the occasional broken down scout.
Use the tonnage you save from a rational stovage of the X-boats to install a more conventional bay. And/or design your X-boats and scout/couriers to be the same shape.


Hans
 
Use the tonnage you save from a rational stovage of the X-boats to install a more conventional bay. And/or design your X-boats and scout/couriers to be the same shape.


Hans

Same hull, cone; the scout version has J2-M2, and the x boat j4 OR

Same hull, wedge:...

Actually, that makes production lines more efficient.
 
Morning Carlobrand,

... I'm trying to keep the same design and changed the length and redrawing the deck plans. ...

Oh, dude, you are brave.

Not brave at all considering I'm trying to minimize the changes needed to support the original background material by keep the tender's shape as shown on the deck plans.

My deck plan revision affects the bridge/accommodation deck and ship/vehicle bay.

The bridge/accommodation deck is being revised because I do not buy that 8 tons or 40% of a 20 ton bridge is dispersed as airlocks, ship lockers, and subsumed in to the bulkheads, decks, and overheads.

The ship/vehicle bay's dimension is 40 m x 28.5 m x 12 m which calculates to a volume of 13,680 m^3 or approximately 977 tons. The bay's tonnage doesn't leave room to install anything more than a 20 ton bridge and the Model/3 computer's 3 tons.

You can revise the size and deck plans - but it is a daunting task to design it to take on four x-boats (which are about the worst possible shape for storing in what amounts to an oval box) and meet the other criteria.

By volume a 600 ton bay does allow four x-boats or two scout/couriers to fit inside the ship/vehicle bay. Unfortunately, the dimensions and shapes of the x-boats and scout/couriers were not checked on how they would fit inside the bay.

My best effort stacks the four x-boats in a 39 meter long, 12 meter tall, 24 meter wide oval tube while eliminating that left-hand section with the elevator and the hallway, and it still comes out with 760 dTons for the boat bay. Personally, I like it: I moved the bridge/quarter deck aft between the boat bay and the fuel/engine decks, so that I didn't need that elevator to communicate between fore and aft. I switched from the canon H drives to E drives, which Book 2 says are adequate and which gave me some tonnage to work with. I lost the cargo bay, the extra tonnage I'd gotten off the drives, and most of my extra fuel in the effort to be able hold the 4 xboats, but it's long enough and wide enough to stack four x-boats and two scouts. I get 4 57 dTon decks aft of the boat bay: a 55 dTon engine deck with a couple dTons for fuel, a 57 dTon quarters deck with part of the bridge, and two 57 dTon fuel decks (with a half dTon cut out of each for an elevator through them from the engines to the quarters). It's 12 dTons shy of target, so a 12 dT bridge extension juts out below, just behind the boat bay doors. I get 115 dTons fuel, which serves the ship with only 5 dTon to spare; tempted to convert that to cargo. I don't have any other ideas.

First my apologies if I seem to be nitpicking the proposed re-design of the x-boat tender I'm just trying to make sure I'm understanding the design based on the background material presented in Supplement 7.

The hemisphere, the bow, of one x-boat has a diameter of 12m making that point the widest point all around the hull. At the stern, the smallest portion of the truncated cone, appears to be 3 meters in diameter.

The tender's bay of 12 m in height fits with the solid frame brackets used to secure any x-boats carried when the ship/vehicle bay doors are closed.

Putting the x-boat's 22 m length into the 24 m bay width works for me.

My hang-up is that I can't seem to visualize how the four x-boat hulls fit the length.

The primary purpose of the lift shaft/elevator is to move people between the decks and when the internal communications systems are down to run messages. Personally, I would have one lift shaft and the other one would be an enclosed walkway in case the lift was out of service. The observation platform/hallway appears to be where the tender's crew controls the docking of the x-boats in the bay, coordinates the minor repairs, and shifting material from the cargo deck.

Losing the cargo bay eliminates the storage space for consumables, food, repair parts, and replacement equipment used by the tender's crew and restocking an x-boat before sending it onto the next destination.

Yep, using the type E drives and power plant is a good idea since the second edition allows the change.

The "extra 40 tons of fuel" is dedicated to completely refuel one x-boat after a four parsec jump. One hundred tons of fuel is allocated for the tender's jump drive and ten tons to operate the power plant/maneuver drive.

Dipping into the tender's jump fuel allocation allows two additional x-boats to be completely refueled and prevents the tender from making a jump until being refueled.

My understanding is that the entire hull is 39 m long x 24 m wide x 12 high.

Each deck I am guessing is also 24 m wide by 12 m high.

What is the distance of the remaining third dimension, which is the space between the front and back bulkheads separating each deck?

Again apologies if I appear to be nitpicking.[

QUOTE]If I had been designing this thing from scratch, I'd have designed the tender first then designed x-boats to suit my tender.[/QUOTE]

That method works too.
 
Use the tonnage you save from a rational stovage of the X-boats to install a more conventional bay. And/or design your X-boats and scout/couriers to be the same shape.


Hans

Meh. I am slow of wit this week. :o

Okay, we can make an x-boat tender with dedicated x-boat bays and still have room for a multipurpose bay.

Let's look at another angle: making the existing design work. This might have been mentioned before. The ship can be made to work in more or less its current configuration IF .... dun dah daaaaaaaah ... you assume that stupid bay is open to space when it jumps. At that point the ship ceases to be 1400 dTons and becomes 1400 dTons less the volume of that bay (~975 dTons), plus the volume of the ships carried. In other words, it becomes a dispersed structure with externally docked ships in a kind of open well.

How to make that work:

Let's begin with the decks. At 30 meters by 12 meters, assuming a 3 meter deck, those decks are about 73 dTons. Ship has 400 dTons available after setting aside 600 for bay space. (We'll stick to that so we don't have to make too many changes.) That translates to 5 decks, plus 35 dTons elsewhere - maybe a half deck on the fuel deck, we'll think about it.

Engine deck: 73 dTons. Canon uses H-Drives, which are 85 dTons. Two choices: revert to the more correctly sized E drives at 55 dTons and pick up 30 dTons to add to our cargo or fuel, or add the 35 dT half deck to the engine deck. Let's stick with canon for the moment, keep things simple. 72 dTons engine room, a dTon elevator which I will say is included in the engine space because it's part of the working space the engineer needs, we need 12 dTons elsewhere.

Fuel deck: 73 dTons. Two of these, so 146 dTons. 143 dTons fuel plus a dTon for the elevator on each deck, plus here there be a pop-turret (we'll call it 2 dT), 146 dTons. 7 dTons of fuel needs to be elsewhere. (I'm not taking the elevator cost from fuel - I'll take it from the quarters later.)

Cargo Deck: 73 dTons. Errata puts cargo at 85 dTons now. Okay, the whole deck is cargo. There's an elevator running through here, so it's actually 72 dTons of cargo here (and the elevator charged to the quarters) and 13 needs to be elsewhere.

Bridge deck: 73 dTons. Bridge at 20 dTons. Computer at 3 dTons. 10 Quarters at 40 dTons - and we pay for the elevator on the cargo and fuel decks (did I mention I was nitpicky?*), so subtract 3, 37 dTons up here for quarters. 2 turrets at 2 dTons. If we move the 20 low berths upstairs, that's another 10 dTons. Comes to a total of 72 dTons, with 1 dTon for something else - a bit of cargo, maybe. That fit quite nicely.

Half deck: 35 dTons. Hmmm, let's see ... we needed 12 dTons more for the drives. We needed 7 more dtons for fuel. We needed 12 dTons for cargo (13 less the 1 on the bridge deck). I missed 4 dTons somewhere, never have been able to match canon numbers, they're in error, I think; we'll add that to cargo space. We'll sandwich the half deck between the engine and fuel deck, make those a wee bit taller, allow for a bit of cargo on the engine deck, we'll be fine.

Now we have that boat bay - 40 meters by canon - plus 5 1/2 decks totaling 16.5 meters, length becomes 56.5 meters. There's an elevator running through here, but I'll charge that to the bay volume - as with the engine room, it's part of the working space folk in the bay need to do their jobs.

And now the trick: the ship cannot jump with the x-boat bay closed. It's an open well. There are doors to close over the well when repair work is being done on a ship, but usually they are retracted and the little ships dock to docking ports within the well. If there's a sudden urgent need to jump, whatever ship is in the well is lashed down, the crew leave the well, and the well is opened for jump. There are three docking ports on that left-hand wall where x-boats can dock and the crew move directly from the x-boat to the elevator via the x-boat's airlock. Trick is that the x-boat does not dock in line with the ship; it docks with its butt end sticking out of what would be the bay doors. It's only flat in the bay if it's in there for repair work. Pilot exits his ship at a right angle to the up-down of the elevator.

If you look at the Supplement 7 deck plans, you will see an iris port to the left of the cargo elevator, in the ceiling of the cargo deck, leading to the bridge deck. Move it to the right side, put an iris port in the floor as well; cargo deck now accesses the bay via what is the bay's ceiling. If there's a boat docked at the elevator, a boat docked at the ceiling position right next to that boat lines up its airlock with that iris port.

A better solution is to add an elevator on the right side. Now the ship can dock six x-boats.

Et voila. 56.5 meters long, 30 meters wide, 12 meters high, minor modifications to the deck plan, overall external appearance is about the same, and the existing plan does what canon says it can do - it just needs to keep its well open for jump. An interesting side benefit is that, with those H drives and when not carrying ships, the tender can make 3G and jump-3 with its current fuel.

Now let's talk about those drives. Supplement 7 says it uses H drives. Book 2 says it needs E drives. 30 dTon difference. Replace the H drives with E drives, and you can add a 30 dTon ship's boat back near the engine room for fueling and other errands - something which the ship lacks. With E-drives, the ship can still make 2G and jump-2 when not carrying ships. It can be sent out to recover broken down scouts, following their route across two parsec gaps, and with a boat to handle refueling. It'll be limited to jump-1 and 1G for the return trip, so some thought will need to be given for fueling the return trip: perhaps collapsible fuel bladders in the cargo bay to allow it to make two consecutive jump-1's.
 
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...
The ship/vehicle bay's dimension is 40 m x 28.5 m x 12 m which calculates to a volume of 13,680 m^3 or approximately 977 tons. ...

Why are we getting different values? Oh, I see. You're calculating for a rectangular solid and then using 14 cubic meters to the dTon. If you look at the deck plan, you can see that the floors are oval. You have to calculate the volume as a half-cylinder on either side plus a rectangular solid in the middle. Therefore:

PiR2L for the two half cylinders, where L is the longest dimension, plus L*(W-2R)*H for the central block. R in this case is half of H, the smallest dimension.

So, Pi*(6)2*40+40*(30-12)*12=4524+8640=13,164 cubic meters. At 13.5 cubic meters per dTon (since I'm using the deck plan, where a dTon is a 1.5 by 3 by 3 volume), 975 dTons. Then you subtract the volume for that elevator, which is honestly a guesstimate 'cause I can only guess at the angle of the arc: I get about 7 square meters times the height of 40, or 280 cubic meters. So, 12,884 cubic meters for the bay less the elevator. At 13.5 cubic meters per dTon, 954 dTons. Elevator is 21 dTons through the bay.

But that depends on how fussy one wants to be about the bay volume. I just, you know, find the adding and subtracting and multiplying bit to be fun. One way or another, you could almost fit an x-boat tender in the bay of an x-boat tender, which is very much an Escher moment.
 
Hello Hans,

There's no need to do that. Just put the X-boats in cone-shaped bays with domed hatches. That carries them at 100% of tonnage (or 105% if we follow another ship design system, as I would prefer). You do need to be able to utilize the space in between, and if you don't want to use if for fuel tonnage, you might have some waste space. Nowhere near double up, though.


Hans

What other design system allows for carrying a big craft at 105% or 105/100 = 1.05 times hull tonnage?


Book 2 1st or 2nd edition does not specific how much space is required to carry small craft, vehicles, or hull >=100 tons. Small craft and vehicles are carried in a space equal to their own tonnage.

Supplement 7 gave the x-boat tender a 600 ton bay to carry 400 tons of x-boats. My calculations 600/400 = 1.5 x 100% = 150%

Book 5 2nd edition page 32 defines an 100-to x-boat or 100 ton scout courier as a big craft (hulls > 99 tons) and require the bay to be 110% or 1.1 tons the carried vehicles tonnage.

A 100 ton hull requiring 110% of space for a bay is 110 tons. The extra 10 tons is 135 m^3 of space around the x-boat's widest dimension of 12 m subtracting the points that are next to the ceiling and the inside of the bay doors. Per Supplement 7 each x-boat gets 50 extra tons or 675 m^3 of space surrounding the hull.

Pulling anthropometric data from my copy of AIA Architectural Graphic Standards Student Edition purchased in the early 1990s to help me in drawing a deck plan the average male has a standing height of 1770 mm x 450 mm at the shoulders x 195 mm between the forehead and the back of the head. If I'm doing the conversion correctly the average male is 1.77 m x 0.45 m x .195 m and occupies 0.1553 m^3 of space.

I'm guessing there is probably more than enough space to work around the hulls.

Having 250% or 150 tons of space to work in would I guess be large enough to remove the jump drive from the drive deck and have the replacement at hand. This would be in my opinion a major repair.

Per the Supplement 7 background data the tender provides minor repair services. Externally, I'm guessing would be replacing any antennas carried on the hull or repairing damaged sections of the hull. Internally, the repairs would be replacing seals on the airlocks, replacing blown fuses, or pulling/replacing a bad data storage component or communicator.

Somewhere in the past replies I tried finding good data on the set up for the hangar bay on an aircraft carrier. So far I've only found the one photo I linked to.

The mercenary cruiser's modular cutter bays are, I think anyway, similar to the suggestion being made for the x-boat.
 
Howdy Carlobrand,

Thank you for the math lesson, which I really like.

Why are we getting different values? Oh, I see. You're calculating for a rectangular solid and then using 14 cubic meters to the dTon. If you look at the deck plan, you can see that the floors are oval. You have to calculate the volume as a half-cylinder on either side plus a rectangular solid in the middle. Therefore:

PiR2L for the two half cylinders, where L is the longest dimension, plus L*(W-2R)*H for the central block. R in this case is half of H, the smallest dimension.

So, Pi*(6)2*40+40*(30-12)*12=4524+8640=13,164 cubic meters. At 13.5 cubic meters per dTon (since I'm using the deck plan, where a dTon is a 1.5 by 3 by 3 volume), 975 dTons. Then you subtract the volume for that elevator, which is honestly a guesstimate 'cause I can only guess at the angle of the arc: I get about 7 square meters times the height of 40, or 280 cubic meters. So, 12,884 cubic meters for the bay less the elevator. At 13.5 cubic meters per dTon, 954 dTons. Elevator is 21 dTons through the bay.

But that depends on how fussy one wants to be about the bay volume. I just, you know, find the adding and subtracting and multiplying bit to be fun. One way or another, you could almost fit an x-boat tender in the bay of an x-boat tender, which is very much an Escher moment.

Here is how I did my calculations, which falls under the keep it simple sailor, I know the final letter is for a different word but I figure being a retired sailor I can use it.

One ton occupies a space of 1.5 m x 3 m x 3 m or 13.5 m^3 or 14 if you round up. The drives and power plant require at least 55 tons or 13.5 x 55 = 742.5 m^3 or 14 x 55 =770 m^3 of space. The tender is 30 m wide and 12 m high.

?m x 30 m x 12 m = 742.5 m^3 = 742.5/(30 x 12) = 2.0625 m or
?m x 30 m x 12 m = 770 m^3 = 770/(30 x 12) = 2.1389 m

Since 2.0625 and 2.1389 are a bit difficult to draw I used 3 meters which gives the deck the dimensions of 3 m x 30 m x 13 m = 1,080 m^3 or 80 tons.

Of course since I have both Microsoft Excel or OpenOffice Clac spreadsheets I use there goal seek feature now.

The Consolidated Errata has the cargo deck being 85 ton which using the formula ?m x 30 m x 12 m = 85 tons * 13.5 = 1147.5 m^3 has the missing meter equaling 3.1875 or ?m x 30 m x 12 m = 85 tons * 14 = 1190 m^3 has the missing meter equaling rounded to the fourth place 3.3056.

Rounding to 3 meters using 13.5 m^3 gives me a more space in engineering and less space on the cargo deck.

 
Hello again Hans,

QSDS1.5. GT. T4, I think. Possibly FFS. It's the tonnage for custom-fitted bays, so only one shape fits.


Hans

Thank you for the sources

QSDS 1.5 was something that IIRC that Donald McKinney mentioned a while back when I did some work on T4 errata for him. I could have sworn I got copy, but I seem to have miss placed the darn thing. Is there a site I can get a copy of the file.

T4 Book 1 QSDS has a table for small craft hangars and launch port is on page 112. The minimal hangar space for a 10 to craft is 20 tons and a spacious hangar is 40 tons.

T4 Book 2 Starships page 73 Step 10 Select miscellaneous features does not mention a specific number that I can tell. The Consolidated T4 Errata mentions David Golden created a revised SSDS that that is in a PDF. Can anyone help me find this one too.

GT and GT: Starships also has vehicle bays at 1.05.

Thank you again Hans for the help.

Never mind I found my copies of the SSDS and QSDS 1.5
 
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Express Boat tender pop turret and mobile turrets round 2

Hello all,

Before getting to the real topic I'm thinking that the express boat tender may be a hybrid design between Book 2 and HG2. Supplement 7 page 14.

"Although essentially unstreamlined, the tender is aerodynamic enough to allow skimming from gas giants, thus making acquisition of hydrogen fuel a matter of only minor importance."

Being "aerodynamic enough to allow skimming from gas giants" seems to be a HG2 partially streamlined design.

Okay back to the topic

In Post 98 I commented that the pop turret and two mobile turrets left me unsure how they affected the tonnage and cost of the express boat tenders hull.

My impression from Supplement 7 page 11 is that express boat tenders have the non-standard turrets installed but the are empty since "weapons costs have not been included in this price."

During my search for any bit of information on the non-standard pop turret and mobile turret I came found a reference to pop turrets in Challenge 25 published in 1986. Challenge 25 has the article "Bait: Q-Ships in Traveller" by Steven Brinich and James Schwar on pages 32-33 and 38.

On page 33 in the Design and Construction section is this detail.

"For extra combat power, Q-ships typically carry a maximum number of turrets, with any turrets over and above the usual number of the merchant ship being in the form of pop turrets such as found on x-boats, should be x-boat tenders. The pop turrets installed on Q-ships do not move except to retract and extend, and they include stabilizing gear (tonnage equal to turret tonnage, MCr0.1 per ton)."

The stabilization gear would make a Book 2 turret go from 1 ton to 2 tons (Fire Control + Stabilization Gear) and cost for a single turret from MCr0. 2 to 0.3, the Double/Dual turret would go from MCr0.5 to 0.6, and a triple mount would go from MCr1 to MCr1.1.

I have run the express boat tender through my spreadsheet based on Book 2 2nd edition with the expected results that my MCr and tonnages aren't matching with the published match.

The express boat pop turret appears to be a triple turret from the fuel plan deck plan detail. If the turret is a triple mount the MCr would be 1.1. Including the hard point this turret is MCr1.2

The fire control is what causes a turret to take up one ton of hull space. From the looks of the pop turret detail the whole turret takes 2 tons.

My efforts have failed to find anything more on mobile turrets, which means I'm trying to figure out how they affect the design on my own.

From the turret detail above the bridge deck the tender's mobile turrets are single turrets.

The one ton of fire control is located in the turret which suggests that none of the fire control tonnage is in the tenders hull.

The mobile turret design also suggests that either no hard point is needed or that each mobile requires additional hard points securing the tracks to the hull. My guess is that they need the four hardpoints each securing the tracks to the hull.

Since the turrets are mobile in addition to the normal systems allowing the turret to rotate additional systems are required to move the turret along the track.

Basing my idea from the pop turret I'm thinking that the system needed to move the turret adds 1.5 tons to the turret and MCr0.15 per ton.

Putting all of this together a single mount mobile turret would be 2.5 tons or maybe not since the component is on the external hull and cost MCr0.25.

If the mobile turrets don't require one or more hardpoints then there is not additional cost. However, if one or more hard points are needed then the cost of the hull goes up.

Would something like what I suggested work, especially with a final draft?
 
...In Post 98 I commented that the pop turret and two mobile turrets left me unsure how they affected the tonnage and cost of the express boat tenders hull.

My impression from Supplement 7 page 11 is that express boat tenders have the non-standard turrets installed but the are empty since "weapons costs have not been included in this price."

During my search for any bit of information on the non-standard pop turret and mobile turret I came found a reference to pop turrets in Challenge 25 published in 1986. Challenge 25 has the article "Bait: Q-Ships in Traveller" by Steven Brinich and James Schwar on pages 32-33 and 38.

On page 33 in the Design and Construction section is this detail.

"For extra combat power, Q-ships typically carry a maximum number of turrets, with any turrets over and above the usual number of the merchant ship being in the form of pop turrets such as found on x-boats, should be x-boat tenders. The pop turrets installed on Q-ships do not move except to retract and extend, and they include stabilizing gear (tonnage equal to turret tonnage, MCr0.1 per ton)."

The stabilization gear would make a Book 2 turret go from 1 ton to 2 tons (Fire Control + Stabilization Gear) and cost for a single turret from MCr0. 2 to 0.3, the Double/Dual turret would go from MCr0.5 to 0.6, and a triple mount would go from MCr1 to MCr1.1.

I have run the express boat tender through my spreadsheet based on Book 2 2nd edition with the expected results that my MCr and tonnages aren't matching with the published match.

The express boat pop turret appears to be a triple turret from the fuel plan deck plan detail. If the turret is a triple mount the MCr would be 1.1. Including the hard point this turret is MCr1.2

The fire control is what causes a turret to take up one ton of hull space. From the looks of the pop turret detail the whole turret takes 2 tons.

...

Let's begin with: the price of the tender is one of the few things about it that is correct. I get MCr274.77, which is what the supplement gives as the price. Therefore, there was - when the ship was designed - no effect on the price. Whether there was an effect on the tonnage, probably not: I actually show 4 dTons more space available, which goes against the hypothesis that the turrets were costing more tonnage. I would again caution against using the deck plan to infer tonnage, as we know the deck plan is pretty wildly off.

That's not to say we shouldn't consider errata'ing in a cost in tonnage or credits for pop-turrets retroactively. I can't really see why a pop turret should take up much more space than a regular turret mechanically. I don't think you need an entire dTon of machinery to lift the thing into position. However, it's an interesting balance effect to keep the things from being abused, so probably useful from that perspective. If we're going to incorporate the Challenge article into canon shipbuilding, it'd probably be a good idea to revise the tender to add that bit in.

... My efforts have failed to find anything more on mobile turrets, which means I'm trying to figure out how they affect the design on my own.

From the turret detail above the bridge deck the tender's mobile turrets are single turrets.

The one ton of fire control is located in the turret which suggests that none of the fire control tonnage is in the tenders hull.

The mobile turret design also suggests that either no hard point is needed or that each mobile requires additional hard points securing the tracks to the hull. My guess is that they need the four hardpoints each securing the tracks to the hull.

Since the turrets are mobile in addition to the normal systems allowing the turret to rotate additional systems are required to move the turret along the track.

Basing my idea from the pop turret I'm thinking that the system needed to move the turret adds 1.5 tons to the turret and MCr0.15 per ton.

Putting all of this together a single mount mobile turret would be 2.5 tons or maybe not since the component is on the external hull and cost MCr0.25.

If the mobile turrets don't require one or more hardpoints then there is not additional cost. However, if one or more hard points are needed then the cost of the hull goes up.

Would something like what I suggested work, especially with a final draft?

I have several problems here. First and foremost, there's no combat effect for the tracked turrets. It makes for a nice story in Supplement 7, but neither of the CT rules systems, not Book 2 nor High Guard, sets any limit on a ship using all its available weapons while docking or undocking a subsidiary craft. That leads to problem 2: players are not going to want to be charged an extra cost or an extra charge in hardpoints or tonnage for a system that doesn't have any effect in combat.

Problem 3 lies in the nature of the hardpoint: we really don't know what it is. It's an arbitrary convention. We really don't know why you couldn't mount two or three or four missile or sandcaster turrets to a scout/courier: they don't represent much hull stress whether firing or just sitting there. That being said, we don't have any basis for suggesting that a tracked turret would take up more hardpoints than a regular turret.

I would suggest that we not charge an additional cost in tonnage, credits, or hardpoints for a design element that has no impact in the combat system. The pop-turret is one thing: it makes it possible for a ship to disguise its firepower. The tracked turret is quite another thing: it doesn't provide any measurable benefit. It amounts to an alternate way of doing things, a clever flourish by the designer that looks nifty but doesn't have a game effect. As such, it shouldn't come with added cost - the manufacturer wouldn't offer an option that cost more and didn't provide some benefit.
 
Let's begin with: the price of the tender is one of the few things about it that is correct. I get MCr274.77, which is what the supplement gives as the price. Therefore, there was - when the ship was designed - no effect on the price. Whether there was an effect on the tonnage, probably not: I actually show 4 dTons more space available, which goes against the hypothesis that the turrets were costing more tonnage. I would again caution against using the deck plan to infer tonnage, as we know the deck plan is pretty wildly off.

That's not to say we shouldn't consider errata'ing in a cost in tonnage or credits for pop-turrets retroactively. I can't really see why a pop turret should take up much more space than a regular turret mechanically. I don't think you need an entire dTon of machinery to lift the thing into position. However, it's an interesting balance effect to keep the things from being abused, so probably useful from that perspective. If we're going to incorporate the Challenge article into canon shipbuilding, it'd probably be a good idea to revise the tender to add that bit in.

Let me be a little more specific the Bait: Q Ships in Traveller is in JTAS 25 which at the time was part of Challenge 25. FFE 008 JTAS Issues 25-33 are canon material.

The article uses the 20% discount for standard designs which strongly suggests that the pop turret is an item created for CT Book 5 High Guard 2nd edition.

The pop turret, in my opinion, at the very least is an addition to the design and construction rules for Book 5 2nd edition. However, the pop turret was originally introduced in a Book 2 design which, again in my opinion, needs to be included in the design and construction rules.

In theory the mobile turret takes the place of fixed turrets that would have needed hardpoints, fire controls, and weapons installed to cover the same positions on the hull. Instead of a turret and one ton of fire control a track is attached to the hull using the hardpoint not being used by a fixed turret.

To make a turret a pop turret a mechanism is needed to raise and retract the turret, fire control, and weapons out of or into the hull. The same applies to changing a fixed turret to one that is mobile. In the case of the mobile turret a mechanism is needed to move the turret on the tracks installed along the hull.

I can not see how adding bits and pieces to standard systems does not increase MCr and/or tons of space needed in the hull. Okay, the mobile turret is an exception since the one ton of fire control is not inside the hull. However the mechanism that moves the turret and the tracks have to cost something.

I have several problems here. First and foremost, there's no combat effect for the tracked turrets. It makes for a nice story in Supplement 7, but neither of the CT rules systems, not Book 2 nor High Guard, sets any limit on a ship using all its available weapons while docking or undocking a subsidiary craft. That leads to problem 2: players are not going to want to be charged an extra cost or an extra charge in hardpoints or tonnage for a system that doesn't have any effect in combat.

Problem 3 lies in the nature of the hardpoint: we really don't know what it is. It's an arbitrary convention. We really don't know why you couldn't mount two or three or four missile or sandcaster turrets to a scout/courier: they don't represent much hull stress whether firing or just sitting there. That being said, we don't have any basis for suggesting that a tracked turret would take up more hardpoints than a regular turret.

I would suggest that we not charge an additional cost in tonnage, credits, or hardpoints for a design element that has no impact in the combat system. The pop-turret is one thing: it makes it possible for a ship to disguise its firepower. The tracked turret is quite another thing: it doesn't provide any measurable benefit. It amounts to an alternate way of doing things, a clever flourish by the designer that looks nifty but doesn't have a game effect. As such, it shouldn't come with added cost - the manufacturer wouldn't offer an option that cost more and didn't provide some benefit.

Problem 1: "First and foremost, there's no combat effect for the tracked turrets."

Problem 2: "players are not going to want to be charged an extra cost or an extra charge in hardpoints or tonnage for a system that doesn't have any effect in combat."


Supplement 7 page 14 Peculiarities first paragraph, the last two sentences: "Further, although the tracked turrets are a reasonable idea for the situation they are intended to cope with, they are poorly equipped to handle many other situation. As a result, any weapons on express boat tenders can be expected to fire at -1 at all times.".

Does a -1 to fire at all times affect combat?

Problem 3 Part A: "lies in the nature of the hardpoint: we really don't know what it is. It's an arbitrary convention."

I may be taking things out of context, but in the real world a hardpoint is a strengthening of certain points to the internal or external structure of an aircraft's frame and points on the wings. There purpose is to allow the mounting of different items to the aircraft.

Here is a link to a site showing the weapons load of an F-15, http://fas.org/man/dod-101/sys/ac/f-15.htm.

The location of the missiles, bombs, and wing tanks are hardpoints.

The Titanic and her sisters had hardpoints included in the design so that they could be armed in time of war.

Problem 3 Part B: "We really don't know why you couldn't mount two or three or four missile or sandcaster turrets to a scout/courier: they don't represent much hull stress whether firing or just sitting there. That being said, we don't have any basis for suggesting that a tracked turret would take up more hardpoints than a regular turret."

In Book 2 we don't know why there can be only one jump drive, maneuver drive, or power plant other than the rules say so. In the case of hardpoints and turrets the designers and play testers decided that one hardpoint per one hundred tons of hull fit the game balance they were going for.

We don't know how 50 kg/110 lb. missiles or 50 kg/110 lb. sandcasters are launched either so how do we know how much stress is applied to the turret and supporting structure.

Problem 3 Part B: "we don't have any basis for suggesting that a tracked turret would take up more hardpoints than a regular turret."

The best example I can think of in the real world is something like the monorail in Seattle, WA. The rails are fixed to the top of pillars, a kind of hardpoint in my opinion, allowing the monorail to move from point to point. At stations where the monorail stops to take on or off load passengers there are more pillars/hardpoints supporting the weight of the monorail, tracks, station on the passengers.

Change the monorail car into a mobile turret running on a track along the exterior of a ship's hull does in my little fuzzy bit of old gray matter makes sense that more than one hardpoint is needed.

Here is another way to look at the reason why a mobile turret needs more hard points than a fixed turret.

I'm going to change the two mobile turrets to fixed which now leaves both sides of the tenders hull exposed to fire. To cover this gap I install a turret on each side. The tons needed is for the four turrets is 4 x one ton of fire control and cost is (4 x turrets MCr) + (4 hardpoint MCr).

After a bit more pondering a mobile turret doesn't take up any internal space from the hull since the fire control is part of the mobile turret's structure.

I think we both agree that there will be a cost for turret and fire control of a mobile turret. Further the first hardpoint is something I think we agree on.

Does it make sense that a turret that includes parts to move it along a length of track cost the same as a standard turret and only need one hardpoint to support the tracks and the turret?
 
snrdg - That article postdates the design by many years. It couldn't have been used in the design of any of the ships in Sup 7.
 
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