Internal Layout & Deck Plan — Design Research

Draft Medium Research 4,407 words Created Mar 4, 2026

Vessel Internal Layout & Deck Plan

Research into the internal arrangement, deck zoning, and space allocation for The Claw — a converted Aframax tanker operating as a mobile plasma processing vessel in the Great Pacific Garbage Patch, 1,000 nm from Honolulu.

Vessel basis: Aframax tanker, ~245m LOA, ~44m beam, ~14-15m loaded draft, 80,000-120,000 DWT. Double hull construction per MARPOL requirements. Approximately 5,500-8,000 m2 of main deck area available for topsides equipment and structures.

1. Deck Zones & Space Allocation

The main deck is divided into functional zones running bow to stern. This follows FPSO conversion precedent where topsides modules are arranged longitudinally with pipe racks and walkways between them. Standard FPSO practice maintains a 3m perimeter egress zone from hull edge to outermost module edge, and 1m minimum clearance between modules.

Zone Map (Bow to Stern)

BOW ──────────────────────────────────────────────────────────── STERN[Helipad]  [Accommodation]  [Processing Core]  [Collection/Receiving]  [Bridge]
 & FwdMooring  & Utilities     & Power Gen        & Pre-Processing     & Nav
  ~30m          ~45m            ~80m               ~60m                 ~30m
                                                                     (superstructure)

Note: This is a significant departure from standard FPSO practice, which typically places accommodation forward and the flare tower aft. Here, the collection interface needs to be at or near the stern/sides where boom recovery equipment operates, and the bridge/navigation must maintain sightlines to collection operations. Accommodation goes forward (upwind of processing exhaust in prevailing trade winds). The helipad goes at the bow, furthest from hot exhaust and collection operations.

Space Allocation Table

Zone	Deck Area (m2)	% of Total	Notes
Processing Core	1,800-2,200	~30%	Reactor, syngas cleanup, power gen
Collection & Receiving	1,200-1,500	~20%	Boom handling, dewatering, shredding, pre-sort
Crew Accommodation	800-1,000	~14%	Multi-deck superstructure (3-4 levels)
Helipad	500-600	~8%	Including safety perimeter and refueling
Storage (deck-level)	400-600	~8%	Spare parts, consumables, hazmat staging
Workshop & Maintenance	300-400	~5%	Machine shop, electrical shop, plasma torch rebuild
Safety Systems	200-300	~4%	Lifeboats, davits, firefighting stations
Utility Systems	300-400	~5%	Watermaker, HVAC, sewage, electrical switchgear
Bridge & Navigation	150-200	~3%	Standard tanker bridge, extended with operations center
Walkways, Egress, Pipe Racks	400-600	~7%	3m perimeter + inter-module access
TOTAL	~5,500-7,500	100%

Below deck utilization is covered separately in Section 6. The former cargo tanks add an additional ~15,000-20,000 m3 of enclosed volume.

2. Helipad Requirements

The Problem: 1,000 nm from Honolulu

This is the single hardest logistics constraint. No conventional helicopter can fly 1,000 nm one-way from Honolulu, land, and return.

Helicopter Range Comparison

Aircraft	Type	Range (nm)	D-Value (m)	Max Gross Weight (kg)	Can Reach 1,000nm?
Sikorsky S-92	Medium twin	539-547	20.88	12,020	NO (half the range needed)
AW139	Medium twin	675	~17.1	6,800	NO
AW189	Super-medium	~500	~17.6	8,600	NO
MH-60T Jayhawk	USCG medium	260 (operational)	~19.8	10,660	NO
Bell Boeing V-22 Osprey	Tiltrotor	1,000+ (unrefueled)	~25.8 (rotors folded: ~19.2)	27,443	YES (military only)

Realistic Medevac Strategy

No civilian helicopter can reach this vessel from Honolulu. The realistic options are:

1. USCG HC-130J fixed-wing — Long-range SAR aircraft (2,900+ nm range). Can reach the vessel, orbit overhead, coordinate rescue, drop supplies and rafts. Cannot land on the vessel. USCG Air Station Barbers Point, Oahu operates these.

2. USCG relay medevac — HC-130J flies to location, helicopter (MH-60T) deploys from a closer platform or vessel. This is how USCG already handles deep-ocean rescues from Hawaii. Documented cases show medevacs at 175-210 nm offshore, with HC-130 providing overhead support for longer missions.

3. V-22 Osprey — The only rotorcraft with 1,000+ nm range. Military asset, not available on-demand for civilian medevac. Theoretically capable with 2,100 nm self-deploy range. Would require a pre-arranged military partnership, not a reliable primary medevac plan.

4. Relay vessel with helicopter — A supply/crew-change vessel stationed partway (e.g., 500 nm out) carrying a medium helicopter. Expensive. Unlikely.

5. Ship-based medevac to range of shore helicopter — Fastest practical option. A fast crew boat or the vessel itself repositions toward Honolulu while a USCG helicopter launches to intercept. At 15 knots, the vessel closes 360 nm in 24 hours. The USCG Jayhawk's 260 nm operational radius means a rendezvous is possible within ~30 hours.

Recommendation: Design the helipad for an S-92 class helicopter (the offshore industry standard), accept that most helicopter access will come via supply vessels carrying their own helicopters, or from military assets in extremis. The helipad's primary utility is for crew-change operations when the vessel is closer to port (during transit, resupply cycles), and for receiving helicopters deployed from passing vessels or military ships.

Helipad Physical Requirements (S-92 Class)

Per CAP 437 (UK CAA, the international benchmark standard for offshore helidecks) and API RP 2L:

Requirement	Specification
Landing area diameter	1.0 x D-value minimum = 20.88m. Recommended: 1.25 x D = ~26m circle
Structural load	75% of max gross weight as concentrated load = 9,015 kg (~88.4 kN) at any point
Dynamic load factor	1.5x for emergency/hard landing = 18,030 kg equivalent
Deck construction	Aluminum preferred (40-60% lighter than steel). Non-slip surface.
Obstacle-free zone	210-degree sector clear of obstacles above helideck level. No structure taller than 25mm within the D-circle except essential aids.
Safety net	1.5m wide perimeter net (5m net for vessels), extending beyond deck edge
Lighting	Perimeter lights (green), floodlights, approach path lighting, status lights (red/green), wind direction indicator illuminated
Markings	'H' marking, D-value, maximum weight, vessel name, TD/PM circle, aiming circle
Firefighting	Minimum two foam monitors covering entire deck, 6,000 liters AFFF foam, rescue equipment locker
Fuel storage	Jet A-1, quantity depends on operations tempo. Minimum 5,000-10,000 liters for occasional operations. Stored below helideck in dedicated tank.
Refueling system	ICAO-compliant aviation fuel dispensing with grounding, filtration, water separation

Hangar vs. Landing Pad

A full hangar is not warranted. The vessel does not carry its own helicopter. An open helideck with a small helicopter reception facility (HRF) — a wind-sheltered equipment store for firefighting gear, stretcher, refueling equipment — is sufficient. Approximate footprint:

Helideck landing area: ~26m diameter circle = ~530 m2
HRF and support equipment: ~50 m2
Total helipad zone including safety perimeter: ~600 m2

Location: Forward, at bow or on elevated structure above bow mooring equipment. This positions the helipad upwind of exhaust stacks and processing emissions in the prevailing NE trade winds, and maintains obstacle clearance for approach/departure over open water forward.

3. Processing Area Detail

What Does a Marinized Plasma Reactor Installation Look Like?

The processing core is the densest and heaviest area on the vessel. Based on the PAWDS installation on Gerald R. Ford-class carriers, the PRRS at Hurlburt Field, and general plasma gasification plant layouts:

PAWDS Reference (Shipboard Proven)

The PAWDS system installed on CVN-78 USS Gerald R. Ford:

Processes 200 kg/hour (~4.8 TPD) of mixed solid waste
Compact, all-electric system (no refractory brick — a major weight and maintenance advantage)
Sequence: shredder → mill (reduces to powder) → plasma-fired eductor → destruction chamber
Plasma temperature: 5,000C+
One-button start/stop
No visible plume or heat signature
Lloyd's Register MED Type Approved

Physical characteristics (estimated from Navy documentation and comparable systems): The PAWDS unit fits within a ship compartment roughly 8-10m long x 6-8m wide x 4-5m high, excluding the shredder/mill intake system. This is for 4.8 TPD. The Claw needs 5-10 TPD — roughly 1-2x PAWDS capacity.

PRRS Reference (Land-Based, 10.5 TPD)

The Hurlburt Field PRRS installation:

10.5 metric tonnes per day — close to The Claw's target throughput
Designed as transportable (containerized)
Energy-neutral: syngas powers the system's own electrical needs with surplus returned to grid
Processes municipal solid waste, biomedical waste, and hazardous waste
Outputs: vitrified slag + electricity

Physical characteristics (estimated from comparable plasma gasification facilities): A 10 TPD plasma gasification plant typically occupies 0.5-2 acres (2,000-8,000 m2) as a land installation. However, this includes vehicle access, buffer zones, office buildings, and site infrastructure. The core reactor and gas cleanup equipment — the parts that would go on a ship — occupy roughly 20-30% of that footprint: approximately 500-1,500 m2.

Processing Core Layout on The Claw

MIDSHIPS PROCESSING ZONE (~80m long x 25m wide = ~2,000 m2)

┌──────────────────────────────────────────────────────────────────────┐ │ │ │ ┌─────────┐ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │ │ │ Syngas │ │ PLASMA │ │ Syngas │ │ Power Gen │ │ │ │ Turbine/ │ │ REACTOR │ │ Cleanup │ │ Switchgear │ │ │ │ Generator│ │ CHAMBER │ │ (scrubber, │ │ & Electrical│ │ │ │ (~400m2) │ │ (~500m2) │ │ cooler, │ │ Distribution│ │ │ │ │ │ │ │ filter) │ │ (~200m2) │ │ │ │ │ │ 4-6m tall │ │ (~400m2) │ │ │ │ │ └─────────┘ └──────────────┘ └──────────────┘ └──────────────┘ │ │ │ │ ┌─────────────────────────┐ ┌──────────────────────────┐ │ │ │ Plasma Torch Storage │ │ Slag Cooling & Handling │ │ │ │ & Rebuild Station │ │ Conveyor to Storage │ │ │ │ (~100m2) │ │ (~200m2) │ │ │ └─────────────────────────┘ └──────────────────────────┘ │ │ │ └──────────────────────────────────────────────────────────────────────┘

Key Physical Requirements

Headroom: The reactor chamber requires 4-6m internal headroom minimum. Most plasma reactors are vertical cylinders. Including the steel frame/module structure above the main deck, total height from deck to top of exhaust stack could be 10-15m. This is comparable to standard FPSO topsides modules, which typically rise 10-20m above deck.

Foundation: The reactor and gas turbines are the heaviest single items. They require structural stools (steel support structures) that distribute load directly to the hull's longitudinal and transverse bulkheads below. FPSO practice is to mount topsides modules on stools that align with the hull's internal structure. The reactor should sit directly above a transverse bulkhead intersection for maximum structural support.

Exhaust routing: Syngas combustion exhaust routes through a scrubber/cleanup system before exiting via a stack. The stack must be positioned to keep exhaust clear of the accommodation block (forward) and helipad (forward). Standard practice: stack amidships or slightly aft, minimum 15m above deck level, with a 210-degree clear zone around the helipad approach.

Vibration isolation: Plasma torches operate at extreme temperatures but relatively low vibration. The gas turbine/generator is the primary vibration source. Standard marine vibration mounts (resilient mounts) on the genset skid. The reactor chamber sits on fixed stools — vibration is not a major concern for the static reactor vessel.

Access for maintenance: PAWDS was designed for one-button operation, but plasma torches have finite life (~1,000-2,000 hours depending on feedstock) and require replacement. The reactor design must allow:

Torch replacement from outside the chamber (withdrawal from torch ports)
Overhead crane or hoist rated for torch weight (~50-200 kg per torch)
Full walk-around access with minimum 1.5m clearance on all sides
Slag tap access from below (if gravity-fed slag removal)

Fire rating: A60 fire-rated boundaries between the processing zone and adjacent zones. This is standard FPSO practice and SOLAS requirement.

4. Collection Interface

How Plastic Gets from Ocean to Processing Deck

This is the least proven part of the system. The FPSO industry moves fluids through risers. The Claw must move solid debris — wet, tangled, mixed with marine growth — from sea level to processing equipment 15-20m above the waterline.

Collection System Architecture

STERN/SIDE COLLECTION ZONE (~60m long x 20m wide = ~1,200 m2)

OCEAN SURFACE │ ┌──────────┴──────────┐ │ Boom/Net Array │ │ (deployed by crane │ │ or A-frame davit) │ └──────────┬──────────┘ │ ┌────┴────┐ │ Recovery│ ← Stern ramp, side port, or │ Opening │ over-the-side conveyor └────┬────┘ │ ┌──────┴──────┐ │ Dewatering │ ← Inclined screen conveyor │ Station │ gravity drain + squeeze rollers │ (~200m2) │ target: reduce water content from └──────┬──────┘ ~70% to ~20% before processing │ ┌──────┴──────┐ │ Pre-Sort │ ← Manual + magnetic separation │ Station │ remove: metal, rocks, large marine │ (~100m2) │ organisms, hazardous items (drums, └──────┬──────┘ batteries, unexploded ordnance) │ ┌──────┴──────┐ │ Shredder/ │ ← Industrial marine shredder │ Grinder │ reduces all material to <50mm │ (~150m2) │ including fishing nets (critical) └──────┬──────┘ │ ┌──────┴──────┐ │ Buffer │ ← 24-48 hours of processed feedstock │ Storage │ decouples collection from reactor │ (~300m2) │ operations (collection is weather- └──────┬──────┘ dependent; reactor runs 24/7) │ TO REACTOR ──→

Boom/Net Recovery Equipment

A-frame davit or stern gantry — rated for 5-10 tonnes, for deploying and recovering boom arrays and nets. Similar to oceanographic research vessel stern gear or trawl winches.
Side-mounted cranes — 2x deck cranes (SWL 10-15 tonnes each), port and starboard, for handling debris bags, super-sacks, and boom sections. Standard offshore crane technology.
Stern ramp option — a partially submerged stern ramp (like a landing craft or stern trawler) allows direct conveyor contact with the water surface. This is the most efficient method for continuous collection but requires significant hull modification.
Over-the-side conveyor — an inclined belt conveyor that reaches from deck level to below waterline. Simpler than a stern ramp. The 4ocean OPR vessel uses a davit with 2,000 lb capacity to haul super-sacks of collected plastic.

Dewatering

Ocean plastic arrives saturated with seawater. Water is heavy, corrosive, and reduces plasma efficiency. Dewatering stages:

1. Gravity drain — inclined screen conveyor lets bulk water drain back to sea 2. Squeeze rollers — mechanical compression removes interstitial water 3. Thermal drying — waste heat from reactor exhaust used to further dry feedstock in a rotary dryer or heated conveyor section

Target: reduce moisture content from ~60-70% (as-recovered) to <20% (reactor feed specification).

Buffer Storage Between Collection and Processing

This is critical. Collection depends on weather, daylight, sea state. The reactor needs continuous feed 24/7. The buffer decouples these:

Below-deck hoppers or bins holding 24-48 hours of shredded, dewatered feedstock
Estimated volume: 50-100 m3 (shredded plastic at ~200-400 kg/m3 loose bulk density)
Fed to reactor via screw conveyor or belt conveyor from below

5. FPSO Layout Precedents

What Can We Borrow from the FPSO Industry?

FPSOs are the closest industrial analogue to The Claw: a tanker hull converted to a floating industrial processing facility, operating offshore for extended periods. Key layout principles:

Precedent: Standard FPSO Topsides Arrangement

Typical FPSO layout (bow to stern): 1. Turret/mooring (bow) 2. Accommodation (forward, upwind of process areas) 3. Utilities (power generation, water treatment) 4. Processing modules (separation, compression, water injection) 5. Offloading (stern)

Modules are organized on stools with pipe racks between them. The industry standard is 13 mid-size modules (300-2,000 tonnes each) or 6 large modules (3,000-5,000 tonnes each) for a large FPSO. The Claw's processing equipment is simpler than an oil/gas FPSO — fewer fluid systems, no high-pressure gas, no flare tower — but the plasma reactor is heavier per unit area.

Directly Applicable FPSO Principles

FPSO Principle	Application to The Claw
Accommodation always upwind of process area	Forward accommodation, processing midships/aft
3m perimeter egress zone around all modules	Same — escape route around entire deck
A60 fire-rated boundaries between zones	Between processing, accommodation, and storage
Module stools aligned to hull structure	Reactor foundation on bulkhead intersections
Topsides weight < 20,000 tonnes (large FPSO)	The Claw probably 3,000-5,000 tonnes total topsides
Min 3m air gap between deck and module underside	Allows inspection, piping runs, cable trays below modules
Module length < L/10 of hull	For 245m hull, max module length = 24.5m
Heavy equipment on centerline	Reactor and gensets on vessel centerline
Helideck on separate elevated structure	Bow helideck above mooring deck
Hull stores liquid (crude oil in FPSO; ballast water in The Claw)	Former cargo tanks become ballast, freshwater, slag storage

Key Differences from FPSO

No risers or subsea interface — The Claw collects from the surface, not the seabed
No flare tower — syngas is consumed on-board, not flared
No crude oil storage — former cargo tanks repurposed entirely
Solids handling — FPSOs move fluids; The Claw moves solid debris (conveyors, cranes, hoppers)
Lower crew count — typical FPSO: 40-80 crew; The Claw: 20-28
Lower overall topsides weight — no gas compression, no water injection pumps, no heavy separators

6. Below Deck Utilization

An Aframax tanker has ~90,000-115,000 m3 of cargo tank volume, typically arranged as 10-16 tanks in a centerline + wing tank configuration with double-hull construction. Port, center, and starboard tanks separated by longitudinal oil-tight bulkheads.

Tank Repurposing Plan

Former Tank	New Purpose	Volume (est.)	Notes
Center tanks (2-3 tanks)	Ballast water (primary)	15,000-25,000 m3	Active ballast management for stability
Wing tanks (4-6 tanks)	Ballast water (trim/heel)	10,000-15,000 m3	Port/starboard balance
1 center tank	Fresh water storage	2,000-3,000 m3	Fed by watermaker, supplies crew + process
1 center tank	Feedstock buffer storage	2,000-4,000 m3	Shredded/dewatered plastic ready for reactor
1-2 tanks	Inert slag storage	3,000-6,000 m3	Vitrified slag (inert, non-toxic, density ~2,500 kg/m3)
1 tank	Fuel oil storage	2,000-3,000 m3	Backup fuel for generators during startup/low-plastic periods
1 tank	Hazardous waste isolation	500-1,000 m3	Separated items that cannot be plasma-processed
Slop tanks (aft)	Grey/black water treatment	500-1,000 m3	Sewage treatment plant located here
1 wing tank	Aviation fuel (Jet A-1)	50-100 m3	Isolated, fire-rated, vented per aviation standards
Void spaces	Remain void	Various	Structural inspection access, emergency buoyancy

Ballast Management

This is critical for an FPSO conversion and even more so for The Claw, because the topsides weight changes as plastic is collected, processed, and slag accumulates.

Operating displacement varies: At startup (empty slag tanks, no feedstock) vs. full operation (slag accumulating, feedstock buffer full). The difference could be 500-2,000 tonnes.
Active ballast system required: automated ballast pumps that adjust water volume in real-time to maintain target draft and trim.
Anti-roll tanks: Passive or active anti-roll tanks (U-tube type) reduce beam motion. Important because the processing deck has hot equipment and conveyors that are sensitive to excessive roll.
Ballast water treatment: Required under IMO Ballast Water Management Convention. The vessel will exchange enormous volumes of Pacific Ocean water — must have UV treatment or electrochlorination system to prevent biofouling and invasive species transfer.

Can Cargo Tanks Become Processing Chambers?

Not recommended. While theoretically possible to install the reactor inside a former cargo tank:

Access for maintenance is severely restricted through tank manholes
Headroom in Aframax cargo tanks is ~15-18m (sufficient), but width between longitudinal bulkheads may be only 10-14m
Exhaust routing from below deck to atmosphere is complex and creates fire risk
Vibration and thermal expansion of the reactor would stress the hull structure
Emergency access/egress is difficult
SOLAS and class society rules for enclosed space hot work are extremely restrictive

The reactor goes on the main deck, on stools. Below-deck tanks are for storage and ballast only.

7. Weight & Stability

Topsides Weight Estimate

Component	Estimated Weight (tonnes)	Location
Plasma reactor + chamber	200-400	Centerline, midships
Syngas cleanup system	100-200	Centerline, midships
Gas turbine/generator (2 MW class)	80-150	Centerline, midships
Emergency/backup diesel generator	40-80	Aft of processing
Shredder/grinder system	30-60	Aft, near collection
Dewatering equipment	20-40	Aft, near collection
Conveyors and material handling	40-80	Distributed
Cranes (2x deck cranes)	60-100	Port/starboard, aft
Boom handling A-frame/davit	30-50	Stern
Accommodation module (28 crew, 3 levels)	300-500	Forward
Helipad structure (aluminum)	30-50	Bow, elevated
Piping, electrical, HVAC, misc.	200-400	Distributed
Workshop and stores	50-100	Forward/midships
Safety equipment (lifeboats, davits, firefighting)	40-60	Distributed
TOTAL ESTIMATED TOPSIDES	1,220-2,270

Comparison: Large oil/gas FPSOs carry 20,000-25,000 tonnes of topsides. The Claw's ~1,500-2,000 tonnes is modest by FPSO standards. An Aframax hull with 100,000 DWT capacity has enormous reserve for this topsides weight.

Center of Gravity Considerations

Following FPSO design principles:

1. Heaviest items on centerline — the reactor, gensets, and gas cleanup are all on the vessel centerline. This minimizes heel (permanent list).

2. Heavy items low and midships — the reactor is the single heaviest topside item. Placing it at midships minimizes trim (bow/stern imbalance) and places it near the vessel's center of buoyancy. The 3m air gap between deck and module underside (FPSO standard) raises the effective CG of topsides equipment, but this is unavoidable for maintenance access.

3. Ballast compensates for asymmetric loading — the collection equipment and cranes are aft and outboard. Ballast tanks forward and to port/starboard compensate.

4. Monitor CG continuously — as slag accumulates (below deck, low CG, good) and feedstock is consumed (deck-level buffer depleted, CG shifts), the ballast system must actively compensate. This is standard FPSO practice.

5. Worst-case stability check — full slag storage + full feedstock buffer + full accommodation + helicopter on pad + worst-case wind heel. Naval architect must verify GM (metacentric height) remains positive with adequate margin under all loading conditions per MARPOL/SOLAS intact and damage stability criteria.

Vertical CG Budget (Rough Order)

Item	Height above keel (m)	Weight (tonnes)	Moment (t-m)
Ballast water (lower tanks)	5	30,000	150,000
Slag storage (tanks)	5	1,000 (full)	5,000
Fuel oil (tanks)	7	2,000	14,000
Hull steel	8	15,000	120,000
Topsides equipment	20	1,500	30,000
Accommodation (3 levels)	25	400	10,000
Helipad (elevated)	28	40	1,120
Total		~50,000	~330,000
Effective KG	~6.6m

This is rough, but the key takeaway: the enormous hull weight and low ballast water keeps the overall KG low despite the elevated topsides. An Aframax tanker's KG in ballast condition is typically 7-9m above keel. Adding 1,500 tonnes of topsides at 20m above keel shifts KG upward only modestly because the topsides are a small fraction of total displacement. Stability is not a limiting factor for this conversion.

8. Crew Accommodation Detail

Requirements for 28 Crew on 28-Day Rotations

Per SOLAS and the Maritime Labour Convention (MLC 2006), minimum standards apply. Offshore industry practice exceeds minimums significantly for retention.

Accommodation Block Layout (Forward Superstructure, 3-4 Levels)

Level	Contents	Area (m2)
Level 1 (main deck)	Galley, mess hall (seats 28), dry stores, cold stores, laundry	250-300
Level 2	14x twin-berth cabins (each ~9-12 m2), shared bathroom pods	250-300
Level 3	Officers' cabins (6x single, ~12-15 m2 each), ship's office, medical bay	200-250
Level 4 / Bridge deck	Bridge, radio room, operations center, captain's day cabin	150-200

Cabin Standards (MLC 2006 Minimum / Offshore Typical)

Feature	MLC Minimum	Offshore Typical
Floor area (single)	5.5 m2	10-15 m2
Floor area (double)	7 m2	12-16 m2
Berth width	680mm	800mm
Headroom	2.03m	2.2-2.4m
Furniture	Bed, locker, desk, chair	Plus en-suite wet room, TV, reading light, power outlets

Other Accommodation Facilities

Recreation room — TV, library, gym equipment, table tennis (~40-60 m2)
Medical bay — examination room, 1 bed, basic surgical capability, telemedicine equipment, defibrillator, oxygen, drug safe (~20-30 m2). At 1,000 nm from shore, the vessel must be self-sufficient for medical emergencies for at least 48-72 hours.
Laundry — industrial washer/dryers, drying room for outdoor work gear (~15-20 m2)
Smoke room / outdoor break area — designated smoking area away from hazardous zones

9. Utility Systems

Watermaker (Reverse Osmosis)

Crew of 28 x ~200 liters/day (drinking, cooking, showering, laundry) = 5,600 liters/day
Process water needs (dewatering backwash, cooling, cleaning): ~5,000-10,000 liters/day
Total demand: ~10,000-15,000 liters/day (10-15 m3/day)
A compact marine RO watermaker producing 15-20 m3/day fits in approximately 6-10 m2 of floor space
Redundancy: two units, each capable of full demand, with one as standby
Fresh water stored in a dedicated below-deck tank (2,000-3,000 m3 capacity provides months of reserve)

HVAC

Accommodation block: standard marine HVAC with tropical rating (ambient 35C+, high humidity)
Processing area: forced ventilation for gas detection zones, no air conditioning
Bridge: air conditioned
Workshop: ventilated, not air conditioned
Central chiller plant in utility space, ducted distribution

Sewage Treatment

IMO MARPOL Annex IV compliant sewage treatment plant
28 crew generates approximately 3-4 m3/day of black/grey water
Biological treatment plant (membrane bioreactor or similar), fits in ~15-20 m2
Treated effluent can be discharged overboard (>12 nm from land — not an issue at 1,000 nm)
Located in aft lower deck (former slop tank area)

Electrical Distribution

Primary power: syngas turbine/generator (~2 MW)
Backup power: diesel generator (~1 MW) for blackout recovery and startup
Emergency generator: dedicated SOLAS emergency generator (separate compartment, above waterline)
Distribution: 440V/60Hz main bus, 220V for accommodation, 24V DC for navigation and safety
UPS for bridge, communications, and fire detection systems

10. Safety Systems

Lifesaving

Per SOLAS Chapter III:

Lifeboats: 2x totally enclosed lifeboats, each capable of accommodating 100% of crew (28 persons). One on each side. Free-fall type preferred (faster deployment, no davit failure risk). Each lifeboat ~8-10m long.
Rescue boat: 1x fast rescue craft (FRC), 6-person capacity, for man-overboard recovery
Life rafts: Additional inflatable life rafts (SOLAS pack A) as redundancy, 100% capacity each side
Lifebuoys: 8 minimum, distributed around deck, 4 with self-igniting lights, 2 with buoyant lifelines
Immersion suits: 1 per person + 10% spare

Firefighting

Water-based: Fire main with hydrants and hoses throughout vessel. International shore connection.
Foam: Fixed foam system for processing area (high-expansion foam for enclosed/semi-enclosed spaces)
CO2/clean agent: Fixed CO2 system for engine room, generator room, workshop
Helideck: Dedicated foam monitors and AFFF supply per CAP 437
Detection: Addressable fire detection throughout (smoke, heat, flame detectors). Gas detection in processing area (CO, H2, H2S, LEL).
Portable: CO2 and dry powder extinguishers distributed per SOLAS

Emergency Systems

Emergency generator: Dedicated diesel genset, separate compartment above waterline, auto-start on main power loss. Powers: emergency lighting, navigation lights, fire detection, communications, steering gear.
Emergency towing arrangement: Forward and aft towing bridles (SOLAS requirement for vessels >500 GT)
EPIRB: 406 MHz satellite distress beacon, auto-float type
SART: 2x search and rescue transponders
Satellite communications: GMDSS Area A3/A4 compliant (Inmarsat + VSAT)

11. Workshop & Maintenance Bay

At 1,000 nm from shore, the vessel cannot send equipment out for repair. The workshop must handle:

Capabilities

Machine shop — lathe, milling machine, drill press, grinder, welding (MIG/TIG/stick)
Electrical shop — motor rewinding, cable termination, PLC/instrumentation repair
Plasma torch rebuild — dedicated clean area for torch electrode and nozzle replacement. Torches have limited life (~1,000-2,000 hours) and are the primary consumable.
Hydraulic shop — hose making, pump rebuild, cylinder reseal (for cranes, davits, conveyors)
General maintenance — pipe fitting, gasket cutting, pump overhaul

Space: 300-400 m2

Located forward of processing area, between accommodation and processing zone
Overhead crane (2-5 tonne) for handling heavy components
Direct access to main deck for moving large items
Ventilated, fire-rated separation from adjacent zones

Spare Parts Storage

Minimum 6 months of critical spares carried on board
Plasma torch electrodes and nozzles (primary consumable — estimated 50-100 sets)
Conveyor belts, bearings, seals, filters
Electrical spares (motors, contactors, fuses, cable)
Welding consumables
Approximate storage: 200-300 m2 deck area or below-deck dedicated store

Open Questions & Unknowns

1. Exact reactor dimensions — PyroGenesis has not published marinized PRRS physical dimensions. The PAWDS dimensions are classified/restricted Navy information. All reactor sizing in this document is estimated from comparable land-based systems and industry analogues. Must be resolved with PyroGenesis directly.

2. Stern ramp vs. side collection — the collection interface design is the least mature element. A stern ramp (trawler-style) is mechanically efficient but requires major hull surgery. Over-the-side conveyors are simpler but limited in throughput. Needs marine engineering study.

3. Helicopter operational concept — the helipad is designed and rated, but how it actually gets used at 1,000 nm requires a defined logistics concept. Pre-arranged USCG partnership? Military liaison agreement? Relay vessel? This is an operational question, not a structural one.

4. Syngas turbine selection — the Siemens SGT-50 (~2 MW, compact footprint) is a candidate for syngas-to-power conversion, but syngas from ocean plastic (variable composition, chlorine content from PVC) may require specific turbine modifications or a reciprocating gas engine instead. Needs gas composition analysis from actual GPGP plastic.

5. Slag disposal at sea — vitrified slag is inert and non-toxic, but dumping solid material in international waters falls under the London Convention/Protocol. Even inert material requires a dumping permit. Alternative: accumulate and offload to supply vessel for shore disposal or sale as aggregate. Legal question.

6. Dynamic positioning vs. mooring — at the GPGP location, depth is ~4,000-5,000m. Traditional mooring (anchor + chain) is impractical at this depth. The vessel either uses dynamic positioning (DP, expensive in fuel/power) or free-drifts with the gyre current and periodically repositions. Affects power budget and hull equipment.

7. Class society rules — which classification society (Lloyd's, DNV, ABS, BV) and which notation? An FPSO-type notation? A special-purpose vessel notation? This affects every structural, safety, and equipment decision. Must be decided early in design.