Citizens of the Imperium

Citizens of the Imperium (http://www.travellerrpg.com/CotI/Discuss/index.php)
-   The Fleet (http://www.travellerrpg.com/CotI/Discuss/forumdisplay.php?f=16)
-   -   Non-OTU: Crew requirements (http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=33473)

Adam Dray October 28th, 2014 01:55 PM

Crew requirements
 
This thread is about crew requirements, but a little background first.

I'm building a very nonstandard Traveller universe (Nova Roma) set in 2175 or so. I'm using MgT, but I realize that there's a fair amount of overlap between what I'm doing and with T2300.

In early-stellar Nova Roma, all ships are military (Navy), though transports for colonists and trade follow very quickly. They're all government chartered, though, and only the biggest corporations can play.

Starships do not jump. They travel via sungates (a la Sundiver) that seem to have been constructed by an (absent?) advanced intelligence an indeterminant number of years ago. The sungate is basically a wormhole between two systems and the travel is instantaneous, but then the climb out of the star's gravity well to a planet takes more time. This is done through a kind of stutterwarp via what is called a hackdrive, which allows for high-speed, momentumless travel in normal space. It's very fast, but it is not FTL.

In a brand new system, a starship doesn't have a way to leave. The science team must use modern astronomy and probes to find the location of any sungates in the system's star. This takes 3d6-3 months. The starship carries a nuclear fission plant (usually two, in case one fails) and doesn't need to refuel often. However, it does need to refill the ammonia coolant it needs for travel, which it can do at many planets.

The typical Aquila-class starship is 500 dT. It has a crew of 50 plus bunks for 50 mission passengers. This is typically the ONLY ship sent to a new world to colonize it. It carries military personnel like Marines, but also several science teams and a diplomatic team.

So far, Nova Roma has discovered that most of the systems it visits have Earthlike, habitable planets with humanlike inhabitants. Most of these cultures are low-TL (1-5) with occasional exceptions. Naturally, scientists suspect some kind of "world seeding" by the creator of the sungates.

The starship needs to study a system from afar, determine threat potential, infiltrate the society with spies, learn as much as possible including languages, and then make first contact. The team then welcomes the world into the Nova Roman empire, with some rules and expectations, and a colonization and economic plan. Hostile worlds receive a show of force from orbit.

I looked at modern submarines. Did you know that the fast attacks and fleet ballistic missile subs displace 7,200 tons and 18,750 tons, respectively? Are we supposed to be comparing these to our starships, cuz holy crap.

U.S. Navy subs run three shifts. Basically, everything in Engineering (power, drive, repair), Weapons (weapons, sensors, shields), Operations (astrogation, communication), and Supply (steward, broker) needs three sets of crew. I assume the Executive (pilot, XO, etc.) does, too.

I don't have the stats in front of me at the moment, but I believe I left room for 30 Marines for a ground force, 10 or so on the science and medical team, 10 or so on the diplomatic team, and the remaining 50 for the crew (16 per shift, plus the XO and Captain).

It was interesting creating the deck plan for the ship, since I needed to jam all those bunks in there. I ended up giving the captain a double stateroom, giving officers normal staterooms, and packing other crew into double-occupancy space in several large rooms (assume bunks). I added a small mess area that can seat a fraction of the crew at a time, and an adjoining kitchen (assume refrigeration and food is kept in the floor, mostly).

I tried to plan for traffic flow. 100 people on a 500-dT starship is pretty cramped.

Things I didn't do well: I didn't draw in toilets or showers. I added stairs at the last minute and they're too small. There's not really a rec room or workout room or laundry, and there ought to be. The bridge, built according to the rules, felt unnecessarily large.

I'll share specs and plans at some point.

HG_B October 28th, 2014 02:35 PM

Quote:

Originally Posted by Adam Dray (Post 493979)
I looked at modern submarines. Did you know that the fast attacks and fleet ballistic missile subs displace 7,200 tons and 18,750 tons, respectively? Are we supposed to be comparing these to our starships, cuz holy crap.

A Los Angeles class fully displaces 6,927 tonnes of water. Volume wise a "ton" is 0.9911 m3 water * 6,927 / 14 (dton Trav) = 490 dTons. You might add ~20% for area outside pressure hull.

aramis October 28th, 2014 04:02 PM

The Ohio Class' 18750 displacement tons is 18750 * 35 = 656250 cubic feet.
35.3179 cubic feet per cubic meter gives us roughly 18581 cubic meters.
The Traveller Ton is properly a Displacement Ton, but of liquid hydrogen, not water. It's axiomatically set at a median value of 14 cubic meters. 18581/14=1327.2 Td

So an Ohio is roughly a 1328 Td ship (rounding up). Well inside the design system of MGT.

Traveller makes some interesting assumptions about crew space that are not borne out by current SSBN nor SSAN designs, but are borne out by modern cruise ship designs (if one ignores that the staterooms are typically double occupancy).

A typical USN berth for an enlisted man is about 4 cubic meters, counting the access space and locker, and his share of the head. The mess space runs about 1-2 cubic meters per man, depending upon design.

Note that, in 1920, the L-class submarines in use had "290 cubic feet of air space" per man, about half that of a typical surface ship. ① So, 580 cubic feet per man of airspace - about 1.2 Td (Traveller Displacement Tons).

Note that that 1.2Td per man for a WWI naval vessel was inclusive of the workspaces... but didn't count deck space nor ventilation machinery. (The referenced article from ① is about hygiene in subs.)

You can, and possibly should, consider different sized quartering if you're going to dink with the ship design system at all.

2Td per man, with possible provision for 1Td per man, puts you into bunking still more generous than WW II naval vessels, but noting that they lacked deck space. This space would include designated hallways, bunks (probably lining the hallways), and communal freshers.

As for stewards... The SS United States had roughly 300 stewards ② (of 900 to 1100 total crew, depending upon year) for 1928 passenger berths ③, in 645 passenger staterooms, and was a commercial cruise liner. 1 per 6.5 passengers and officers, roughly. If we count crew as 1/2 a passenger, we get 1 per 7.9 passenger-equivalents; at 1/3, 1 per 7.4. This is based upon 1966 non-automation...

Traveller's 1:8 ratio isn't far from historic marks.

① United States naval medical bulletin, Volume 14, page 8-9
② Shipboard Manpower: A Statistical Study of Men in the United States Merchant Marine
③ wikipedia

pendragonman October 28th, 2014 05:20 PM

Aramis,

Your steward count for the cruise ship, did that count cooks in that or are they still part of the rest of the crew?

Adam Dray October 28th, 2014 05:51 PM

This is all great stuff.

I didn't realize the displacement was liquid Hydrogen instead of water. That makes tons (ha!) of sense. Thanks for the conversion.

Is "Td" the standard unit symbol used in Traveller? I could swear I saw "dT" somewhere.

2 Td per soldier is in line with the MgT double-occupancy rules, actually. Pushing that down to 1 Td/soldier does less violence to my intuition as I draw deck plans. Mind you, that's if I assume that each soldier gets their own bunk and never shares space. If only 1/3 of the crew sleeps at a time, you need much less space for bunks, but you still need the other standard accouterments. I suspect soldiers want their own bunks, though.


One interesting thing about ship design in Nova Roma:

The hackdrive relies on a relativistic bubble around the ship. This 1) eliminates the need for streamlining for entering an atmosphere, and 2) pushes ship architecture toward a more spherical shape, rather than a "torch" design. It gives my ships more of a "fat" profile, which is a lot of fun, but in a lot of ways harder to design deckplans for. (I've dabbled in architecture all my life, so this is fun for me, though.)

HG_B October 28th, 2014 05:59 PM

Quote:

Originally Posted by Adam Dray (Post 494002)
If only 1/3 of the crew sleeps at a time, you need much less space for bunks, but you still need the other standard accouterments. I suspect soldiers want their own bunks, though.

Hot bunking is still required by some of the crew on US attack subs.

aramis October 28th, 2014 06:38 PM

Quote:

Originally Posted by pendragonman (Post 493995)
Aramis,

Your steward count for the cruise ship, did that count cooks in that or are they still part of the rest of the crew?

It counts cooks, wait staff, housekeeping, and on-board store sales clerks.

timerover51 October 28th, 2014 06:56 PM

Quote:

Originally Posted by Adam Dray (Post 494002)
This is all great stuff.

I didn't realize the displacement was liquid Hydrogen instead of water. That makes tons (ha!) of sense. Thanks for the conversion.

Is "Td" the standard unit symbol used in Traveller? I could swear I saw "dT" somewhere.

2 Td per soldier is in line with the MgT double-occupancy rules, actually. Pushing that down to 1 Td/soldier does less violence to my intuition as I draw deck plans. Mind you, that's if I assume that each soldier gets their own bunk and never shares space. If only 1/3 of the crew sleeps at a time, you need much less space for bunks, but you still need the other standard accouterments. I suspect soldiers want their own bunks, though.


One interesting thing about ship design in Nova Roma:

The hackdrive relies on a relativistic bubble around the ship. This 1) eliminates the need for streamlining for entering an atmosphere, and 2) pushes ship architecture toward a more spherical shape, rather than a "torch" design. It gives my ships more of a "fat" profile, which is a lot of fun, but in a lot of ways harder to design deckplans for. (I've dabbled in architecture all my life, so this is fun for me, though.)

I can point you to the general arrangement deck plans for a US Coast Guard buoy tender, that is considerably smaller than your star ship and which had a crew of about 50, if that would help. The plans also show messing areas and stores spaces. The assumed endurance was 60 days, so you would just have to scale that up for stores. The benches in the messing area on the tender were used for storage, as were the benches on the US WW2 submarines. I also have copies of the plans that I could email to you.

timerover51 October 28th, 2014 07:36 PM

Here are some of the dimensions of spaces that I took off of the deck plans. This is for the crew messing area.

Bramble Dimensions

Galley: Fore and Aft, 15.5 feet, Abeam, 15 feet

Crew Mess: Fore and Aft, 22 feet, Abeam, 10 feet

CPO Mess: Fore and Aft, 14 feet, Abeam, 8 feet

Wardroom: Fore and Aft, 17.5 feet, Abeam, forward 17.5 feet, Abeam, aft 15.5 feet

With respect to food storage, 1 mass ton of well assorted rations will occupy about 100 cubic feet or 0.2 Traveller dTons. That will feed, probably more than adequately, 2 to maybe 3 personnel for one year. (If you allow for mixed crews of men and women, use the 3 for lower calorie requirements for the women.) One Traveller dTon is approximately 500 cubic feet, so one dTon of food storage per year for every 10 to 15 crew.

Based on your maximum of 15 months to locate the "sungate", your ship will need food for 24 months as a minimum (I tend to be conservative when it comes to food), although you could go with 18 months. Food for 100 crew for one year will take about 7 dTons of storage, so you will need to allocate about 10 to 14 dTons of storage for supplies. However, if using double-duty space, i.e. benches in mess areas, storage cabinets supporting pool and ping-pong tables, and cargo space in landing craft, you can reduce that by a bit, along with using in-deck storage cabinets, using the between-deck space fully.

aramis October 28th, 2014 09:48 PM

Quote:

Originally Posted by Adam Dray (Post 494002)
This is all great stuff.

I didn't realize the displacement was liquid Hydrogen instead of water. That makes tons (ha!) of sense. Thanks for the conversion.

Is "Td" the standard unit symbol used in Traveller? I could swear I saw "dT" somewhere.

2 Td per soldier is in line with the MgT double-occupancy rules, actually. Pushing that down to 1 Td/soldier does less violence to my intuition as I draw deck plans. Mind you, that's if I assume that each soldier gets their own bunk and never shares space. If only 1/3 of the crew sleeps at a time, you need much less space for bunks, but you still need the other standard accouterments. I suspect soldiers want their own bunks, though.


One interesting thing about ship design in Nova Roma:

The hackdrive relies on a relativistic bubble around the ship. This 1) eliminates the need for streamlining for entering an atmosphere, and 2) pushes ship architecture toward a more spherical shape, rather than a "torch" design. It gives my ships more of a "fat" profile, which is a lot of fun, but in a lot of ways harder to design deckplans for. (I've dabbled in architecture all my life, so this is fun for me, though.)

DT or dT is standard naval shorthand for disambiguation between short tons {T} (US) or long tons {T} (UK), or metric tons {T} (both, sometimes {T Metric}, and Registry Tons (100 cu ft cargo space).

Mongoose may have used dT, but standard use here, for clarity, has been (for about 15 years) Td for Tons Displacement.


All times are GMT -4. The time now is 10:27 PM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright (c) 2010-2013, Far Future Enterprises. All Rights Reserved.