combined steam and gas
Enable an agent to recognise a combined steam and gas marine propulsion arrangement, assess the availability of its propulsion paths, and identify permitted operating or maintenance actions.
Bundle → Layer → Finding → Questions Filled
6 bundles · 11 layers · 15 findings · 27 questions
Propulsion architecture Identify the combination of steam and gas machinery that makes the arrangement COSAG.
Architecture identity
Establish the registered concept and evidence for assigning an installation to it.
COSAG classification
Record the documented meaning of COSAG and the physical features supporting that classification.
- Does the registry's originating record explicitly identify this thing as COSAG marine propulsion? provenance
- Which documented connections demonstrate that steam and gas turbines can jointly supply propulsion torque? definition
Thermal and mechanical boundaries
Separate heat supply dependencies from the mechanical combination of power.
Steam source and drive boundary
Describe steam generation and the path from each turbine to the propulsive load without assuming that a shared label determines the topology.
- Can the steam supply sustain propulsion independently of gas-turbine exhaust, and what evidence establishes this? boundary
- Where do turbine outputs combine, and does propulsion involve direct mechanical transmission or electrical conversion? boundary
Power paths and services Record the dependencies that make steam and gas torque available.
Steam propulsion path
Assess the steam supply and return-cycle interfaces needed for steam-turbine propulsion.
Steam path capability
Record steam conditions, thermal readiness and applicable feedwater and condenser dependencies.
- What inlet pressure, temperature and steam flow are required at each declared propulsion operating point? measurement
- Which boiler, feedwater, condenser or vacuum-system conditions prevent steam propulsion from becoming available? action
Gas propulsion path
Assess gas-turbine readiness and its relationship to common plant services.
Gas path and common dependencies
Record starting, fuel, intake, exhaust, lubrication and control-power dependencies, including dependencies shared with the steam path.
- Which service states must be satisfied before the gas turbine can start and contribute shaft torque? action
- Which shared auxiliary failures can disable both turbine paths despite separate prime movers? boundary
Torque combination and modes Describe how separate turbine outputs become controlled shaft power.
Combining transmission
Map gears, clutches and couplings to allowed torque paths.
Engagement and load sharing
Record clutch engagement constraints, permitted torque direction and combined-load limits.
- Which clutch and coupling states implement steam-only, gas-only and combined drive on each shaft? definition
- What relative-speed, torque and lubrication conditions govern engagement and load sharing? measurement
Transitions and manoeuvring
Record the supported changes in propulsion mode and direction.
Permitted mode transitions
Represent transition prerequisites and the installation-specific means of producing astern thrust.
- What approved sequence and readiness conditions permit adding or removing gas-turbine power while steam propulsion is engaged? action
- How is astern thrust produced, and which propulsion modes support it? definition
- How long does each permitted transition take from its specified initial thermal state? measurement
Performance and protection Connect mode-specific capability to the limits that protect the combined plant.
Mode performance
Record measured or approved output and consumption for each propulsion mode.
Shaft output and endurance
Associate shaft power, fuel demand and operating duration with a defined configuration and test basis.
- What continuous and time-limited shaft outputs are demonstrated for steam-only, gas-only and combined operation? measurement
- What fuel consumption and auxiliary demand accompany those outputs under the recorded conditions? measurement
Combined plant protection
Identify how turbine and transmission protections interact during combined operation.
Trip and torque response
Record protective responses to turbine trips, loss of lubrication and excessive shaft or gear loading.
- When either turbine trips in combined mode, what documented response prevents overload or unintended driving of the disconnected machine? action
- Which overspeed, bearing, lubrication, steam-condition and transmission limits trigger unloading, disengagement or shutdown? measurement
Degradation and service authority Determine remaining propulsion capability and the evidence needed to service the combined arrangement.
Degraded propulsion
Assess faults at both individual power paths and shared transmission equipment.
Remaining drive capability
Link observed faults and isolation states to supported degraded operating modes.
- After a steam-path, gas-path or clutch failure, which shafts remain driveable and at what documented limits? action
- What vibration, oil-debris, leakage or clutch-slip evidence changes the assessment of transmission availability? measurement
Maintenance and acceptance
Record isolation boundaries, service needs and authority for returning the arrangement to operation.
Safe isolation and return
Connect maintenance actions to stored steam energy, fuel supplies, possible shaft rotation and approved acceptance evidence.
- Which approved isolations prevent steam admission, gas-turbine starting and rotation transmitted from the other drive path during the proposed maintenance? action
- Which lubricant, water-treatment and turbine-service requirements apply to the configuration, and where are their intervals specified? provenance
- Which issuing bodies, rule editions and post-maintenance tests govern acceptance of this installation? provenance
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these check these first hold for the sense of combined steam and gas this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these identifiers and schemes hold for the sense of combined steam and gas this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these real-world use hold for the sense of combined steam and gas this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these failure modes and hazards hold for the sense of combined steam and gas this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of combined steam and gas this model covers, and on what evidence? provenance
Classifiers Filled
- Family
- Thing Registry
- Category
- Physical world and living systems
- Entry kind
- thing
- Plane
- PHY
- Domain
- PHY.OBJ
What it is Filled
Combined steam and gas (COSAG) is a marine propulsion arrangement in which a boiler-fed steam turbine and a gas turbine can drive a common propeller shaft through gearing, separately or together.
In scope
- Steam-turbine and gas-turbine power paths and their connection to propulsion shafts
- Steam supply, gas-turbine services and shared auxiliary dependencies at their propulsion interfaces
- Combining gears, clutches, couplings and permitted drive combinations
- Operating modes, transitions, load sharing and manoeuvring capabilities
- Plant-level performance limits, protection, degradation and maintenance readiness
Out of scope
- Detailed standalone models of boilers, turbines, gears and individual auxiliary machines
- Whole-ship design, navigation and mission planning
- Propeller hydrodynamics beyond loads and constraints imposed on the propulsion plant
- COGAS exhaust-heat-recovery architectures and stationary combined-cycle power stations
- Manufacturer product lines and individual ship installations as separate registered kinds
Why it exists Filled
Enable an agent to recognise a combined steam and gas marine propulsion arrangement, assess the availability of its propulsion paths, and identify permitted operating or maintenance actions.
Distinguishing features Filled
- Both steam turbines and gas turbines contribute mechanical propulsion power; a gas turbine used solely for electrical generation does not establish COSAG.
- The arrangement supports a combined steam-and-gas drive mode through transmission equipment; documented naval engineering descriptions also identify separate turbine operation. [Principles of Naval Engineering](https://maritime.org/doc/pdf/engineering.pdf)
- Steam-generation independence must be established to distinguish the intended COSAG architecture from COGAS arrangements dependent on gas-turbine exhaust heat.
- The cruising prime mover is a steam turbine, distinguishing the architecture from diesel-and-gas combinations.
- The registered thing is a propulsion arrangement kind; shaft count, turbine models and installed output describe particular configurations.
What robots and AI may and may not do Filled
Must not
- Operate steam or gas turbine plant without qualified engineers and authority.
- Override boiler or turbine safety systems.
- Misstate the propulsion type of a ship in records.
Only with a human decision
- Any operation of steam plant on preserved ships.
May
- Explain the propulsion arrangement and identify ships that used it from documented sources.
- Describe its historical role in naval ships, citing sources.
Moral aspects Filled
- Steam plant failures have killed engine room crews.
- Asbestos in older steam ships exposes crews and shipbreakers.
Who is affected
- Former crews
- Shipbreakers
- Museum ship staff
Owners Filled
Steward
The navy or owner of each ship; museums for preserved ships.
Links to other meta-models Filled
parent
- Q29380218 - registry parent class
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.combined-steam-and-gas
- Wikidata: Q2544116 (https://www.wikidata.org/wiki/Q2544116)
Direct properties required Filled
- Propulsion topology: Steam turbines and gas turbines mapped through clutches, couplings and gear stages to shafts
- Steam-generation dependency: Independent fired steam supply; exhaust-dependent steam supply; mixed; unresolved
- Permitted propulsion modes: Configuration-specific subset of steam-only, gas-only, combined, stopped and degraded operation
- Available shaft output by mode: kW or MW, with shaft, ambient conditions and continuous or time-limited rating
- Transmission operating envelope: Shaft speed in rpm, torque in kN·m and applicable duration limits
- Steam-path readiness: Cold; warming; ready; supplying torque; cooling; isolated; faulted
- Gas-path readiness: Unavailable; start-permitted; starting; ready to couple; supplying torque; cooling; isolated; faulted
- Mode transition time: s or min, with initial thermal state, initial mode and target shaft output
- Fuel consumption by operating point: kg/h or g/kWh at specified shaft output, mode and fuel basis
- Applicable operating authority: Links to approved machinery instructions, naval or classification rules, trial records and their revisions
Recognition required Filled
- Steam boilers and a gas turbine driving a shared shaft through gearing.
- Funnel arrangements for both boilers and gas turbine exhaust.
Capabilities and actions required Filled
- Classify a documented propulsion arrangement as COSAG or flag unresolved boundaries with neighbouring architectures.
- Trace available steam and gas power paths to each propulsion shaft.
- Assess whether a requested propulsion mode or transition satisfies documented prerequisites.
- Compare mode-specific shaft output, fuel demand and response time using installation evidence.
- Identify propulsion capability remaining after a turbine, clutch or shared auxiliary failure.
- Prepare an isolation or return-to-service assessment for authorised engineering review.
Hazards and failure modes required Filled
- Boiler explosions and steam leaks.
- Fire risk in machinery spaces.
- Asbestos and other hazardous materials in old plant.
Standards and interfaces required Filled
- Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), International Maritime Organization.
Context of use required Filled
- Combined steam and gas propulsion is encountered principally in historical naval engineering and vessels designed around both turbine types.
- The arrangement supports propulsion using steam power, gas turbine power or their combined output through shared transmission machinery.
- Agents may encounter it in machinery plans, engineering archives and assessments of propulsion availability or maintenance requirements.
Sources Filled
- Wikidata item Q2544116: combined steam and gas - identity and sense of the item
- Wikipedia: Combined steam and gas - general description of the item
Open questions
- Does the registry source conclusively identify COSAG marine propulsion, and does an existing Vercy world model already cover this concept?
- How should the boundary with COGAS be expressed for installations that combine independently fired steam generation with some exhaust-heat recovery?
- Which documented COSAG configurations permit gas-only propulsion, and what restrictions apply to reversing and clutch engagement?
- What defensible ranges for shaft power, plant mass, machinery-space dimensions, fuel consumption and transition times can be established from identified installations?
- Which current or historical naval, classification and manufacturer requirements apply to the installations used as evidence, and which failure modes have documented service histories?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q2544116/spec.json