CT Only: Supplement 7 Express Boat Tender

[snrdg082102]

Howdy Patron Zero,

Thanks for trying to get my thread back on course.

If I may, happy to 'nudge' the thread back in the general direction of it's intended subject.

That said, I've always thought the tender should be equipped with a few 'axillary' craft to assist in repairs and general operations.

A sort of BobCat-forklift would be a practical consideration for handling cargo containers or tasked to duties involving scout-courier or x-boat maintenance, perhaps a pair of said utility vehicles to maximize such a resource.

One other thought might be a dedicated drone for fuel-skimming operations, allowing the tender to better utilize it's 'on-station' time when at a maintenance rendezvous point.

I'm guessing that the miscellaneous equipment like the BobCat-forklift is similar to the armament, that being each hull has what was available at the time of construction.

Auxiliary craft nay also fall into the category of they get what the find and pay for at the nearest port.

Per supplement 7 p. 14 "Although essentially unstreamlined, the tender is aerodynamic enough to allow fuel skimming from gas giants, thus making the acquisition of hydrogen a matter of only minor importance."

Unfortunately, Book 2 only has two choices streamlined and unstreamlined hulls. The next issue is how does the tender purify the unrefined stuff sucked up by skimming.

Looks like the author/designer was trying to graft HG rules onto a Book 2 design.

 

[snrdg082102]

Hello Carlobrand,

snip

Point was - back there a bit - that Trav has a few examples of ships with unique design features that don't make it into the ship's pricing. Supplement 9 has this neat "jump ship" that introduces a kind of jump net it uses to transport asteroids and other materials through jump space. No idea what it costs or how much space it takes on the ship when not deployed. It'd be neat to be able to add something like that to the construction rules, but no data.

The tender's price is without turrets, per the description. That means that any add-on of turrets would be by the gamemaster to suit his own needs - whether he wanted the ship unarmed or wanted single turrets with lasers or triple turrets with whatever. That leaves us free to assume the Scout Service paid whatever we happen to think is the appropriate price for the added turrets, and leaves us without a need to errata the stated price of the ship.

Actually there still is the issue that neither a pop turret or a mobile turret can cost the same as the standard turret.

A pop turret is attached to a mechanism that raises and retracts a turret, weaponry, and fire control above the hull plates.

A mobile turret is attached to a mechanism that allows the turret, weaponry, and fire control to move along the hull. The benefit of the mobile turret is the one ton fire control assembly takes up no internal hull space.

At a minimum the two different mechanisms in order to makes sense has added cost to the turret. I'm still of the opinion that the mobile needs more hardpoints than standard turrets, but I'm willing to leave the issue off the cost list..

Hardpoints are, at least in Traveller, used as a place holder that allows the mounting of weaponry in turrets.

Not having a clue on figuring out how much stress accelerating any mass from at rest to even .1G I'll ask the forum.

Does anyone have a guess how much stress punching out 50 kg mass out of a turret would put on a hull's structure?

In Mayday a missile propulsion system appears to have a maximum acceleration rating of 6Gs.

Does anyone have a guess about how much stress punching out a missile at 6G from a turret would put on the hull?

 

[Travellerspud]

Force = Mass x G's (SI units are Kg, Meters, and Seconds)

50 Kg x 588 m/s^2 (6 gs) = 29,400 Newtons

1 Newton is 1 Kg/M/S^2

a .50 caliber M2 machine gun generates ~18,000 Newtons of muzzle force (appx. same for reactive force, assuming no dampers)...or about 2/3 of that 50Kg 6g missile.....so if you can mount a .50 M2, you could likely mount a Traveller missile launcher

of course, lasers have ZERO recoil (not true of plasma/fusion guns)

 

[snrdg082102]

Thanks Travellerspud,

Force = Mass x G's (SI units are Kg, Meters, and Seconds)

50 Kg x 588 m/s^2 (6 gs) = 29,400 Newtons

1 Newton is 1 Kg/M/S^2

a .50 caliber M2 machine gun generates ~18,000 Newtons of muzzle force (appx. same for reactive force, assuming no dampers)...or about 2/3 of that 50Kg 6g missile.....so if you can mount a .50 M2, you could likely mount a Traveller missile launcher

of course, lasers have ZERO recoil (not true of plasma/fusion guns)

Basically punching the missile or a canister out of the confines of the turret probably wouldn't over stress the hull at that point on the first shot.

Well there goes another possible reason why a tender's mobile turret would need more hardpoints I think.

 

[Travellerspud]

There is no rational engineering reason for hard-point limits, this was obviously a game balance technique (and perhaps a rationalization of the "only volume" / "no mass" rule system). Look at a B-17G bomber (not a spacecraft, but more fragile). How many "hard points"? And they just added a bunch from the original...how thick are starship hulls again?

the real limits are mass, drag, power, fire-arcs, and maybe gunner access. but those are not simple to model in a little black book.

however, if you subscribe to the hard point limit philosophy (for whatever reason) then it could be imagined that the "rail system" is attached to multiple hard points, externally sort of...

 

[snrdg082102]

Howdy again Travellerspud,

There is no rational engineering reason for hard-point limits, this was obviously a game balance technique (and perhaps a rationalization of the "only volume" / "no mass" rule system). Look at a B-17G bomber (not a spacecraft, but more fragile). How many "hard points"? And they just added a bunch from the original...how thick are starship hulls again?

the real limits are mass, drag, power, fire-arcs, and maybe gunner access. but those are not simple to model in a little black book.

however, if you subscribe to the hard point limit philosophy (for whatever reason) then it could be imagined that the "rail system" is attached to multiple hard points, externally sort of...

I'm done with the mobile turret issue which has at least temporarily caused me to abandoned my little project trying to bring ships designed using CT Book 2 1977 into line with CT Book 2 1981 making the least amount of changes as possible.

Yes, I do subscribe to the hardpoint limit since that is what the authors/designers/play testers decided was part of the rules set.

Thank you for your response and point of view.

 

[G. Kashkanun Anderson]

I figure the writer of an adventure is just as able to make a mistake as anyone else. And I see no reason to compound the mistake by repeating it. So until you can provide me with an example of an animal called an america or an england or a denmark or a spain or some other country, I do not agree that the writer is entitled.

The turkey.

Less on the nose but still relevant: a lot of domestic breeds are also called simply by their place of origin (Guernseys, Herefords, Shetlands, Brittanys, Dorkings). While, yes, these are technically not their full names ('Guernsey cattle', for example), it is extremely common to refer to them only by their placename descriptor. In fact, that's how the turkey eventually got its name -- from 'turkey cock/hen' a few hundred years ago to just 'turkey' today.

 

[rancke]

The turkey.

The turkey is named for Turkey? My guess is that it's a homonym.

Less on the nose but still relevant: a lot of domestic breeds are also called simply by their place of origin (Guernseys, Herefords, Shetlands, Brittanys, Dorkings). While, yes, these are technically not their full names ('Guernsey cattle', for example), it is extremely common to refer to them only by their placename descriptor.

Only if you're speaking of cows, sheep, horses, so that that part of the name is assumed.

As you say those are abbreviations for much-used names. 'Chamax bug' I'd happily accept. The term is very unlikely to be used enough to have become abbreviated, though.

(I'd still expect 'acid bug' or 'hellbug' to be a more likely coinage on the fly. )


Hans

 

[snrdg082102]

Good Evening all,

I have just been warned that a comment in a post I made could be considered by the moderator as a possible insult and/or a possible attack on another forum member.

My apologies for any inappropriate comments I may have made.

I have agreed to the moderator's request and hopefully the post will reappear at the individual's convenience.

 

[Vargas]

There is no rational engineering reason for hard-point limits, this was obviously a game balance technique . . . Look at a B-17G bomber (not a spacecraft, but more fragile). How many "hard points"?

It's both a game balancing technique and an engineering issue. There's a reason why there weren't even more hard points on the B-17, or a Burke-class destroyer or Iowa-class battleship or what have you, and that has to do with structural integrity, wiring runs, operator space, maintenance access, shock, vibration and thermal loads, weight and balance and a host of other issues.

Another factor not covered, or at least seldom covered well, by RPG design systems is economics. The marginal cost of adding another weapon may be seen as being too high when compared to the perceived benefit of adding it. The extra crew required to operate/maintain some additional capability may be deemed too expensive when it comes to the Navy's ops and maintenance budget.

On this basis, I believe that there are rational engineering (and economic) reasons to have hard point limits.

 

[snrdg082102]

Hello Vargas

It's both a game balancing technique and an engineering issue. There's a reason why there weren't even more hard points on the B-17, or a Burke-class destroyer or Iowa-class battleship or what have you, and that has to do with structural integrity, wiring runs, operator space, maintenance access, shock, vibration and thermal loads, weight and balance and a host of other issues.

Another factor not covered, or at least seldom covered well, by RPG design systems is economics. The marginal cost of adding another weapon may be seen as being too high when compared to the perceived benefit of adding it. The extra crew required to operate/maintain some additional capability may be deemed too expensive when it comes to the Navy's ops and maintenance budget.

On this basis, I believe that there are rational engineering (and economic) reasons to have hard point limits.

Well there goes another good gripe I had while in the USN about not having enough sonar trained bodies to stand all the watches while underway.;-)

Thank you for the additional information.

 

[Terquem]

leaving these numbers here for future ref

The calculated volume of an object comprised of a twelve meter in diameter circle, split in half, and separated by a rectangular space with dimensions

12 meters x 18 meters

extended to a height of 60 meters

should be

19,745.838 cu meters

or 1410.417 dT

 

[Timerover51]

I would view the X-Boat Tender as a standard hull build, considering the number that must exist in the Imperium. As such, assuming the use of E drives and power plant, the engineering spaces would be only 55 tons, not 165, under the 1981 rules, while under the 1977 rules, the engineering spaces would be 85 tons. Either way, you pick up a lot more internal volume. Realistically, to handle a 12 meter diameter X-boat, you should have a 15 meter high clear space to allow for some adjustment of the boats and room to work on them.

 

[snrdg082102]

Hello all,

From CT LBB 2 1977 7th printing p. 11

Power Plant Type E Mass 16 tons
Maneuver Drive Type E Mass 9 tons
Jump Drive Type E Mass 30 tons.

Total: 16 + 9 + 30 = 25 + 30 = 55 tons

The Engineering Space in CT LBB 2 1977 is the same as in CT LBB 2 1981.

Here is the breakdown as far as I can go using CT LBB 2 1981 and CT Supplement 7 pp. 11-15.

Engineering 55 tons + Hangar bay 600 tons + Fuel 150 tons + Bridge 20 tons + Computer 3 tons + Cargo 85 tons (Consolidated CT Errata p. 29) + 3 tons of fire control = 916 tons.

There are ten staterooms of the ten staterooms I am guessing they are standard 4 ton models. The Captain's cabin is probably two standard staterooms. The total for the staterooms is 44 tons making the total 960 tons leaving 40 tons.

The remaining 40 tons are split between the galley, mess and recreation, low berths, electronics shop, machine shop, fuel lab, refueling station, two left shafts, and observation platform.

 

[Terquem]

I see two ways to approach this

First there are the numbers, from the LBB's

You can easily build a 1,000 dton xBoat Tender - it has been shown several times here

Then there is the "space" those numbers are supposed to occupy/be represented by on a playing grid for gamers.

it's the second one where things start to look awkward. I was recently looking at the deck plans for a restored Destroyer of the USN, DE766 (The USS Slater)

Main Deck

now using this as a point of discussion, you can clearly see that playing a game of Make Believe, using miniature figures to represent individuals running about this ship and engaging other individuals in HtH combat, or trying to rebuild the engines would be difficult, if not impossible, as the actual space represented on the drawings for people to stand is, in reality, terribly small.

And we don't like that when we are playing games with miniatures, do we.

So if the Deck Plans for the Make Believe space ship, the xBoat tender, are used for playing games, we want spaces with at least a few squares in each designated area to allow us to place miniatures so that a good "conflict" can be represented.

And this is where the awkwardness is introduced. As is almost universal with the Deck Plans introduced in the CT books, what was drawn to give us an idea of what the ships interior "looked like" does not, cannot, match the numbers derived from the rules for building the ships.

And we go round and round about this because, the deck plan is bigger, so we assign more space to the ship, which means the components occupy more "tonnage" than the rules indicate for a particular cost, so we increase the components to match the tonnage, and now we end up with a bigger ship altogether.

It's sort of circular (companies like SJ Games, then draw bigger deck plans than the original ones, resulting in even bigger volumes, which drive us to bigger displacements, and bigger component values, round and round we go).

My plan is to design a Deck Plan (in AutoCAD) that has the "volumes" I want the xBoat tender to have to adequately represent the spaces the vessel should have in a game I want to run (including sufficient "void" space around an xBoat for securing it in the hanger bay, and accessing its exterior for maintenance and repairs) - and THEN calculate the displacement based upon that volume, and then work backward through B 2 to assign the cost and "technical volume" of the ancillary components.

Does that make sense?

I think I'm actually going to end up with a 1600 dT ship, when I am through.

Oh, and all of this is for a campaign I am going to start that puts the crew of a Tender into a sort of rescue/ "hunt for red October-esque" sort of adventure involving a 300 dt experimental vessel.

 

[mike wightman]

A deckplan can be over by as much as 20% and still considered fit for purpose - LBB2 says so

 

[Vargas]

A deckplan can be over by as much as 20% and still considered fit for purpose - LBB2 says so

Ship designs systems on their own, for the most part, are nice mathematical constructs that don't have to deal with how the components are actually arranged relative to one another physically and how they fit into the hull shape we have in mind. The 20% margin attempts to address this fact so that deckplans are useful gaming aids. Interestingly I've never had players who treated the layout of the ship as anything more than a stage to play upon, so I've never needed them to be that exact.

 

[flykiller]

The 20% margin attempts to address this fact so that deckplans are useful gaming aids.

in my first iteration of the lewis I got to within 3.5 dtons of 4000 dtons with every component exactly spaced. proud of that, a useful exercise, but not worth the effort otherwise. just design a good gamespace that's close enough to the numbers that the players don't notice any discrepancy.

 

[Terquem]

My hanger bay is quite large, as I am designing the tender to have sufficient (i.e. 1.5 m) clearance between each ship, the walls, and the hanger door.

I think I am actually headed toward a 2600 dt tender.

 

[Terquem]

My Express Boat Tender, Preliminary Design Data

My xBoat tender is a hull that is comprised of a main compartment measuring

54m x 24m x 15m for a volume of 19,440 cubic meters

This main compartment includes a single space, rectangular in size equal to 14,000 cubic meters (39 m top to bottom, 24m port to starboard beam, and 15m forward to aft). This space is a dedicated internal ship repair facility and is designed to hold a single express boat, or scout ship, under full repair and includes multiple bridge crane assemblies and two 20 dt “tugs”. Although this is technically a space calculated as 1000 dT, the Ship’s Architect has listed the maximum dt ship that could fit within this bay and be secured for transport as no greater than 700 dT and this only in the most extreme situations. The remaining 388.571 dT of the main compartment is taken up by the engineering bay, 200 dT of fuel, and auxiliary ship spaces including the bridge and computer.

The main compartment is flanked, port and starboard by semi-cylindrical shapes that are 45m long, and have an area of 48.3206 square meters (there are two of them) and this volume equals

4,348.854 cubic meters

- bringing the total volume of this hull to 23,788.854 cubic meters, which would be a 1700 dT vessel (1699.204 dt)

(the semi-cylindrical areas of the sides of the ship are now used as workshops and crew facilities associated with the repair bay, and include machinery to open and close the bay doors, as well as storage tanks for atmosphere recovery)

The 700 dT of the ship’s hull not used for the repair bay volume will have 250 dT of fuel, and be equipped with a Type J power plant, Maneuver Drive, and Jump Drive. This is sufficient to move and power a 2000 dT vessel, and the tender is capable of carrying three additional 100 dT ships docked to its exterior* through Jump Space.

After Engineering space is dedicated (approximately 95 dT), the remainder of the hull space is divided up into crew facilities, data storage/transmission equipment, recreation facilities, cargo spaces, and required bridge/computer spaces. The ship also includes fuel processing equipment but is not streamlined for fuel scoop applications.

*In unusual circumstances, up to two express boats or two scout ships can be “fit” into the repair hanger, but it is a tricky bit of positioning to achieve and requires near expert level Tug Boat pilots to accomplish. In an extreme emergency, cranes, scaffolds, and repair equipment of the hanger bay could be jettisoned, and the Tugs fastened to the hull exterior of the tender to allow any ship not exceeding these dimensions to be fit into the repair bay

22m x13m x 34.5m

(A minimum of 1m to each side of such a carried vessel is required port and starboard, forward and aft, and 3m of clearance is required at the top of the bay, while 1.5 meters is required at the bottom of the bay.)

(Also, through this design process, I modified the basic hull shape of the standard express boat, because I hate curved surfaces quite a bit thank you very much. My express boat is now a single 3m deck that is basically square in shape with 12m sides, this is the crew area and data banks. On top of this is a spherical cap with a radius of 6m, and a height of 4m, giving me a ship control deck 6m square and 3m high, surrounded by astronavigation/sensors/control equipment. The tail of the express boat remains a cone 12m in diameter, and 15m long, ending in a flat surface with a 3m diameter.)