⚓ Working on this equipment?

Ask the AI troubleshooter, log your hours on board and turn them into invoice-ready service reports — for this exact model.

Start free — 14 days →

No credit card required

🔧 23 verified suppliers & service companies for Sulzer in the Maritime Network Find suppliers →

Is Sulzer your company? Claim this page

Sulzer

11RTA84T-D

Name: Sulzer 11RTA84T-D
Brand: Sulzer
SKU: OSE-38707

The Sulzer 11RTA84T-D is an 11‑cylinder low‑speed two‑stroke marine diesel engine delivering ~49.7 MW at 76 rpm, designed for large propulsion applications with constant‑pressure turbocharging.

49720.0 kW

Power

Engine Specifications

Cylinders

840 mm

Bore

3150 mm

Stroke

49,720 kW

MCR Power

76.0 rpm

MCR RPM

2-stroke

Stroke Type

Family: Sulzer RTA · Tier: IMO Tier I · Fuel: HFO, MDO

Inspector Detail ✓ verified

▸

Designation decoded

Sulzer 11RTA84T-D – 11-cylinder two-stroke crosshead engine, bore 840 mm, stroke 3150 mm, T-D series (tanker development variant). Suffix -D = development/further development. ATTENTION: Stroke increased from 2400 mm to 3150 mm – significantly longer-stroke design. Stroke-to-bore ratio 3.75:1 = extremely long-stroke. 11 cylinders combined with increased stroke = exceptional engine length and height.

Background

The 11RTA84T-D represents a fundamental further development of the RTA84T series. The stroke increase from 2400mm to 3150mm (increase of 31.25%) is a drastic change that raises the stroke-bore ratio to an extreme 3.75:1. This design aims at maximum thermal efficiency at very low speeds, which is ideal for tankers with large fixed propellers. The D development brings higher piston speeds despite lower speed, altered vibration characteristics, longer connecting rods and piston rods, as well as increased demands on liner lubrication and piston ring design. The design requires greater engine room height and a reinforced foundation.

Calculated metrics

Stroke To Bore Ratio

3.75

Inspector checklist

Logbook reference values

Parameter	Expected	Deviation means
Zünddruck (Pmax)	130–150 bar (Volllast, VIT aktiv)	D-Version hat angepasste Druckkurven – Abweichungen zwischen Zylindern sorgfältig mit D-Referenzwerten vergleichen
Verdichtungsdruck (Pcomp)	110–128 bar	Bei erhöhtem Hub verändert sich die Kompressionscharakteristik – Abweichungen mit D-Spezifikation bewerten
Exhaust gas temperature per cylinder	330–410 °C	D-Version kann andere Temperaturprofile aufweisen – Spreizung >25 °C zwischen Zylindern untersuchen
Zylinderöl-Verbrauch	0,8–1,3 g/kWh	Erhöhter Hub bedingt größere Schmierfläche – leicht höherer Verbrauch normal; starke Erhöhung = Verschleißproblem
Kolbenstangen-Stopfbuchse Ölverlust	<0,5 l/Zyl/Tag	Erhöhter Hub = erhöhte Stopfbuchsenbelastung; Leckage über Grenzwert = Dichtring-Erneuerung
Kreuzkopf-Führungsspiel	Gemäß D-Spezifikation (größer als Basismotor)	Enlarged clearance = increased wear of guide shoes due to greater lateral forces
Kurbelwellen-Deflection	±0,05 mm	D-Version mit höherem Motorgewicht – Fundamenteinfluss verstärkt
Spülluftdruck	2,5–3,3 bar (Volllast)	Erhöhtes Hubvolumen erfordert angepasste Luftversorgung – Abweichungen sofort untersuchen

Common Failure Modes

Erhöhter Kreuzkopf-Führungsverschleiß

Symptoms: ['Klopfgeräusche im Bereich der Kreuzkopfführungen', 'Enlarged guide shoe clearance during measurement', 'Metallabrieb im Systemöl']

Causes: Elevated lateral forces due to extended stroke, Unzureichende Schmierung der Führungsbahnen, Thermische Verformung der verlängerten Kolbenstange

Preventive: Kreuzkopf-Spielmessung in verkürzten Intervallen, Schmierölversorgung überwachen, Partikelanalyse im Systemöl

Kolbenstangen-Ermüdung

Symptoms: ['Hair cracks at MPI/UT inspection', 'Kolbenstangen-Stopfbuchse vermehrte Leckage', 'Ungewöhnliche Vibrationen']

Causes: Verlängerter Hub erzeugt höhere Wechselbelastung, Operating hour-related material fatigue, Vibration resonance at certain speeds

Preventive: Regelmäßige NDT-Prüfung (MPI/UT) der Kolbenstangen gemäß D-spezifischem Intervall, Schwingungsanalyse

Stopfbuchsen-Überlastung

Symptoms: ['Erhöhter Ölverlust an Kolbenstangen-Stopfbuchse', 'Ölnebel im Spülluftkasten', 'Dichtringverschleiß beschleunigt']

Causes: Increased piston rod speed and stroke, Thermische Belastung der Dichtringe, Oberflächenrauheit der Kolbenstange außerhalb Toleranz

Preventive: Shortened service intervals for stuffing boxes, inspect piston rod surface at overhaul, use D-specific sealing rings

Vibration problems due to altered mass inertia

Symptoms: ['Increased vibrations at certain speeds', 'Rissbildung an Motoranbauteilen', 'Rohrleitungs-Schwingungsbrüche']

Causes: Altered inertial forces due to longer stroke and heavier moving parts, Torsionsschwingungscharakteristik verändert, Barred-Speed-Range möglicherweise verschoben

Preventive: Measure vibration during sea trial and periodically, observe and document barred speed range, inspect engine mounting components for fatigue cracks

Expert tips

💡 T
💡 h
💡 e
💡
💡 D
💡 -
💡 v
💡 a
💡 r
💡 i
💡 a
💡 n
💡 t
💡
💡 i
💡 s
💡
💡 a
💡
💡 f
💡 u
💡 n
💡 d
💡 a
💡 m
💡 e
💡 n
💡 t
💡 a
💡 l
💡 l
💡 y
💡
💡 d
💡 i
💡 f
💡 f
💡 e
💡 r
💡 e
💡 n
💡 t
💡
💡 m
💡 a
💡 c
💡 h
💡 i
💡 n
💡 e
💡
💡 f
💡 r
💡 o
💡 m
💡
💡 t
💡 h
💡 e
💡
💡 b
💡 a
💡 s
💡 e
💡
💡 R
💡 T
💡 A
💡 8
💡 4
💡 T
💡
💡 –
💡
💡 t
💡 h
💡 e
💡
💡 3
💡 1
💡 %
💡
💡 s
💡 t
💡 r
💡 o
💡 k
💡 e
💡
💡 i
💡 n
💡 c
💡 r
💡 e
💡 a
💡 s
💡 e
💡
💡 c
💡 h
💡 a
💡 n
💡 g
💡 e
💡 s
💡
💡 v
💡 i
💡 r
💡 t
💡 u
💡 a
💡 l
💡 l
💡 y
💡
💡 a
💡 l
💡 l
💡
💡 o
💡 p
💡 e
💡 r
💡 a
💡 t
💡 i
💡 n
💡 g
💡
💡 p
💡 a
💡 r
💡 a
💡 m
💡 e
💡 t
💡 e
💡 r
💡 s
💡 .
💡
💡 N
💡 E
💡 V
💡 E
💡 R
💡
💡 u
💡 s
💡 e
💡
💡 b
💡 a
💡 s
💡 e
💡
💡 R
💡 T
💡 A
💡 8
💡 4
💡 T
💡
💡 r
💡 e
💡 f
💡 e
💡 r
💡 e
💡 n
💡 c
💡 e
💡
💡 v
💡 a
💡 l
💡 u
💡 e
💡 s
💡
💡 f
💡 o
💡 r
💡
💡 t
💡 h
💡 e
💡
💡 D
💡 -
💡 v
💡 e
💡 r
💡 s
💡 i
💡 o
💡 n
💡 .
💡
💡 P
💡 a
💡 y
💡
💡 s
💡 p
💡 e
💡 c
💡 i
💡 a
💡 l
💡
💡 a
💡 t
💡 t
💡 e
💡 n
💡 t
💡 i
💡 o
💡 n
💡
💡 t
💡 o
💡
💡 c
💡 r
💡 o
💡 s
💡 s
💡 h
💡 e
💡 a
💡 d
💡
💡 g
💡 u
💡 i
💡 d
💡 e
💡
💡 s
💡 h
💡 o
💡 e
💡 s
💡 ,
💡
💡 p
💡 i
💡 s
💡 t
💡 o
💡 n
💡
💡 r
💡 o
💡 d
💡 s
💡
💡 a
💡 n
💡 d
💡
💡 s
💡 t
💡 u
💡 f
💡 f
💡 i
💡 n
💡 g
💡
💡 b
💡 o
💡 x
💡 e
💡 s
💡
💡 –
💡
💡 t
💡 h
💡 e
💡 s
💡 e
💡
💡 c
💡 o
💡 m
💡 p
💡 o
💡 n
💡 e
💡 n
💡 t
💡 s
💡
💡 a
💡 r
💡 e
💡
💡 d
💡 i
💡 s
💡 p
💡 r
💡 o
💡 p
💡 o
💡 r
💡 t
💡 i
💡 o
💡 n
💡 a
💡 t
💡 e
💡 l
💡 y
💡
💡 l
💡 o
💡 a
💡 d
💡 e
💡 d
💡
💡 b
💡 y
💡
💡 t
💡 h
💡 e
💡
💡 e
💡 x
💡 t
💡 e
💡 n
💡 d
💡 e
💡 d
💡
💡 s
💡 t
💡 r
💡 o
💡 k
💡 e
💡 .
💡
💡 T
💡 h
💡 e
💡
💡 e
💡 x
💡 t
💡 r
💡 e
💡 m
💡 e
💡
💡 s
💡 t
💡 r
💡 o
💡 k
💡 e
💡 -
💡 b
💡 o
💡 r
💡 e
💡
💡 r
💡 a
💡 t
💡 i
💡 o
💡
💡 o
💡 f
💡
💡 3
💡 .
💡 7
💡 5
💡 :
💡 1
💡
💡 i
💡 s
💡
💡 a
💡 m
💡 o
💡 n
💡 g
💡
💡 t
💡 h
💡 e
💡
💡 h
💡 i
💡 g
💡 h
💡 e
💡 s
💡 t
💡
💡 i
💡 n
💡
💡 t
💡 h
💡 e
💡
💡 i
💡 n
💡 d
💡 u
💡 s
💡 t
💡 r
💡 y
💡 .
💡
💡 E
💡 n
💡 g
💡 i
💡 n
💡 e
💡
💡 r
💡 o
💡 o
💡 m
💡
💡 h
💡 e
💡 i
💡 g
💡 h
💡 t
💡
💡 m
💡 u
💡 s
💡 t
💡
💡 b
💡 e
💡
💡 s
💡 u
💡 f
💡 f
💡 i
💡 c
💡 i
💡 e
💡 n
💡 t
💡
💡 f
💡 o
💡 r
💡
💡 t
💡 h
💡 e
💡
💡 D
💡 -
💡 v
💡 e
💡 r
💡 s
💡 i
💡 o
💡 n
💡
💡 –
💡
💡 v
💡 e
💡 r
💡 i
💡 f
💡 y
💡
💡 d
💡 u
💡 r
💡 i
💡 n
💡 g
💡
💡 r
💡 e
💡 t
💡 r
💡 o
💡 f
💡 i
💡 t
💡 .
💡
💡 V
💡 i
💡 b
💡 r
💡 a
💡 t
💡 i
💡 o
💡 n
💡
💡 r
💡 e
💡 p
💡 o
💡 r
💡 t
💡
💡 f
💡 o
💡 r
💡
💡 D
💡 -
💡 v
💡 e
💡 r
💡 s
💡 i
💡 o
💡 n
💡
💡 m
💡 u
💡 s
💡 t
💡
💡 b
💡 e
💡
💡 a
💡 v
💡 a
💡 i
💡 l
💡 a
💡 b
💡 l
💡 e
💡
💡 s
💡 e
💡 p
💡 a
💡 r
💡 a
💡 t
💡 e
💡 l
💡 y
💡 .
💡
💡 B
💡 a
💡 r
💡 r
💡 e
💡 d
💡
💡 s
💡 p
💡 e
💡 e
💡 d
💡
💡 r
💡 a
💡 n
💡 g
💡 e
💡
💡 m
💡 a
💡 y
💡
💡 d
💡 i
💡 f
💡 f
💡 e
💡 r
💡
💡 f
💡 r
💡 o
💡 m
💡
💡 t
💡 h
💡 e
💡
💡 b
💡 a
💡 s
💡 e
💡
💡 v
💡 e
💡 r
💡 s
💡 i
💡 o
💡 n
💡 .

Related components

T u r b o l a d e r ( D - a n g e p a s s t e A b s t i m m u n g ) , L a d e l u f t k ü h l e r , A b g a s k e s s e l , W e l l e n l e i t u n g s l a g e r , S t e v e n r o h r d i c h t u n g , T o r s i o n s s c h w i n g u n g s d ä m p f e r ( D - s p e z i f i s c h ) , B r e n n s t o f f a u f b e r e i t u n g , M o t o r e n f u n d a m e n t ( v e r s t ä r k t ) , K r e u z k o p f - S c h m i e r s y s t e m , K o l b e n s t a n g e n - S t o p f b u c h s e n

Classification & regulatory

D-version requires its own NOx Technical File and EIAPP certificate – NOT transferable from base engine. Torsional vibration report D-specific. Classification society must have approved D-modification. Post barred speed range in engine room. Foundation reinforcement must be approved by class.

Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.

Other Cylinder Configurations 50

Components & Design

Component data being added…

Technical Data

unified from engine model True

🤖 Ask about this model

One free question — answered like a marine engineer. No account needed.

Suppliers & Spare Parts

Direct links to manufacturer, datasheet, spare-parts portal and dealers — request access below.

📄 Request sourcing links & documents

🛠 Manage this equipment in your fleet

Cases, daily reports, timesheets and AI troubleshooting in the OceanSphere Marine app — free for 14 days.

Start free trial →

🔎 Suppliers & service for this equipment

Find manufacturers, repair shops and spare-part dealers in the Maritime Network — our global company directory.

Maritime Network →

Manuals

operating
Sulzer RTA Operating Manual
Wärtsilä Switzerland (historical Sulzer)
maintenance
Sulzer RTA Maintenance Manual
Wärtsilä Switzerland (historical Sulzer)
spare_parts
Sulzer RTA Spare Parts Catalogue
Wärtsilä Switzerland (historical Sulzer)

Working on this unit?

Log hours, photos and findings into an invoice-ready service report — OceanSphere Marine, 14-day free trial.

Need a service partner for Sulzer?

114,000+ shipyards, suppliers and service companies in the Maritime Network directory.

Equipment Model #38707 · ✓ still in production