Diesel Engine revision module 2 of 8

CHK

Daily Engine Checks

Build a repeatable pre-start, after-start, under-load, and post-run evidence loop with clear departure and stop boundaries.

pre-start baselinealarm sequencefluid trendsdeparture decision

8 guided lessons · 8 practice questions · 8 flashcards

3 outcomes · self-guided revision

Build a safe, repeatable pre-start sequence that compares the engine with its own known baseline instead of merely ticking a list.
Use the first controlled minute after start to verify alarms, lubrication, charging, cooling and abnormal sound before committing the vessel.
Inspect the low-pressure fuel path and separator without confusing visible fuel with clean delivery or turning an observation into an unsafe intervention.

A self-guided revision companion that explains essential concepts, then helps you practise and test them. It supports—but does not replace—recognised instruction, practical training, assessment or certification. Access is a one-time payment, not a subscription.

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Lesson 1 of 8

Checks Before Starting

What you will learn

Build a safe, repeatable pre-start sequence that compares the engine with its own known baseline instead of merely ticking a list.

A useful daily check is an evidence-gathering routine: make the machinery safe to inspect, establish the correct measurement conditions, compare with a recorded normal state, then decide whether the engine is ready to start.

Begin with the vessel and engine in a controlled state. Confirm the start control cannot be operated unexpectedly, the gearbox control is in the manual-defined starting position, the engine space is ventilated as required, and clothing, hair, tools and loose gear are clear. A cold engine is normally the safer reference for oil, coolant, leaks and belt inspection, but the exact wait time, dipstick method, cap and valve positions belong to the installed manuals.

Use a fixed route so omissions become visible: engine tray or bilge, fuel source and shut-off state, oil, closed-circuit coolant where fitted, gearbox or saildrive oil if required, seawater intake and strainer arrangement, belts, hoses, clamps, wiring, mounts, controls and loose objects. The list must be adapted to the actual installation; a wet-exhaust yacht, dry-exhaust boat and keel-cooled vessel do not share every check.

Compare, do not just glance. Record the normal cold level, tray condition, separator appearance, belt surface and control positions for this boat. A level inside marks can still be important if it has moved materially since yesterday. Conversely, one favourable cue cannot cancel fresh fuel, oil, coolant or seawater in the tray.

Daily check decision board

Separate the observation from the departure decision

Select a case. The phase, evidence limit, safe decision and release condition are all available as text and do not depend on colour.

COLDPre-start

LIVEAfter start

LOADUnderway

LOGPost-run

The check closes only after the post-run evidence becomes the next reliable pre-start baseline.

1 · Observed

The cold oil level is inside the marks but lower than the comparable logged baseline, with one fresh drop in the tray.

2 · This supports

Stored oil remains within the marked range under this check condition, and a real change may have occurred since the last comparable reading.

3 · This does not prove

The range does not prove running pressure, explain the downward trend or cancel the fresh leak evidence.

4 · Safe decision

Preserve the reading and drop location. Confirm the manual-defined method, then investigate accessible isolated areas before starting.

5 · Release

Comparable level is understood, the source is credibly resolved, the tray remains dry and the manual-defined start verification is available.

Revision model only. It does not approve a departure or diagnose a live engine. Use the exact engine, transmission and installation manuals; keep clear of hot, pressurised, moving, high-current and high-pressure fuel hazards; and obtain recognised practical instruction or qualified help when the procedure or competence is uncertain.

Select a check case and separate what the observation supports from what still needs a safe release decision.

Worked example

The cold oil level is between the marks but is visibly lower than the photograph and log from the previous two checks; a fresh amber drop is present beneath the engine.

1Confirm the boat, dipstick seating and wait condition match the manual-defined baseline before comparing readings.
2Treat the falling trend and fresh drop as linked evidence to investigate; do not top up first and erase the change.
3Trace only accessible, isolated areas permitted by the manual, contain the fluid and decide whether competent help is needed before start.

Sense check: 'Inside the marks' answers one level question. It does not explain a new downward trend and leak evidence.

Checks Before Starting
Pre-start point	Evidence to establish	What it does not prove
Engine oil	Manual-defined cold or settled reading within range and consistent with trend	Running oil pressure or absence of an internal fault
Coolant	Cold reservoir or filler check by the installed procedure	Raw-water flow, heat-transfer performance or a leak-free loaded run
Seawater path	Correct valve/strainer state for this installation	Pump delivery or wet-exhaust discharge after start
Tray/bilge	Known baseline with no unexplained new fluid	That every hose, seal or system remains sound under load

Build a personal normal card

A new skipper needs a routine that another crew member can repeat and report accurately.

1. Map
Use the current manuals to locate the real dipsticks, reservoirs, strainers, valves, filters and isolation controls.
2. Baseline
Record cold levels, tray appearance, belt condition and normal control positions without inventing universal limits.
3. Compare
Ask what changed since the last reliable check, service or run.
4. Decide
Start only when the observed state and unresolved exceptions fit the manual and voyage plan.

Sense check: A checklist becomes useful when two competent people mean the same thing by 'normal'.

Common mistake or limitation

Opening a hot pressurised coolant cap or reaching near belts because the checklist says 'check coolant' or 'check belt'.
Using a generic online layout instead of identifying the actual engine, gearbox, saildrive and cooling arrangement.
Calling any reading between two marks normal without comparing measurement conditions and recent trend.

Recap

Control the machinery state before collecting evidence.
Use one installation-specific route and one repeatable measurement condition.
Compare with a recorded baseline and resolve meaningful changes before start.

Optional quick check

Section 1 of 8

The cold oil reading is within the marks but lower than yesterday and there is a fresh drop below the engine. What is the best interpretation?

Continue

Lesson 2 of 8

After Starting

What you will learn

Use the first controlled minute after start to verify alarms, lubrication, charging, cooling and abnormal sound before committing the vessel.

Starting is not the end of the check. It creates the first live evidence that oil-pressure indication, panel behaviour, charging, cooling and engine response are credible enough to continue.

Observe the panel through its complete start sequence. Note which lamps or audible alarms prove their own test, which clear after the engine fires and which remain. A lamp going out is evidence from that indication circuit; it is not permission to ignore a leak, abnormal noise, smoke or temperature trend. The manual defines the expected sequence and any permitted delay.

For an installation that normally discharges seawater through a wet exhaust, confirm discharge promptly from a safe position. No or markedly reduced water is a stop signal in the referenced Yanmar guidance. Do not universalise that cue to keel-cooled or dry-exhaust arrangements, and do not treat visible water as proof that every cooling passage, coolant circuit or exhaust component is healthy.

Listen, smell and watch before engaging gear: cranking recovery, idle stability, belt noise, vibration, exhaust appearance, fuel or exhaust smell and new leaks. Keep people and loose objects away from rotating machinery. If an oil-pressure warning persists, cooling evidence is absent for an installation that requires it, or another critical alarm remains unexplained, stop as the vessel situation permits rather than warming the fault into a failure.

Worked example

The engine starts smoothly and wet-exhaust water appears, but the oil-pressure warning stays on beyond its normal manual-defined clearing interval.

1Separate the cues: combustion and some seawater discharge are present; safe lubrication is not confirmed.
2Stop as the vessel situation permits rather than increasing rpm to make the warning disappear.
3Preserve the panel sequence and use the exact manual or competent assistance to distinguish indication from an underlying pressure problem before restart.

Sense check: Cooling evidence cannot cancel an unresolved lubrication warning.

After Starting
After-start cue	Supports	Does not establish
Oil-pressure warning clears normally	The monitored warning circuit no longer reports low pressure	That oil level, pressure sender and every lubricated part are fault-free
Charging indication becomes normal	Expected alternator/charging response at that moment	Battery capacity, belt condition or all electrical connections
Wet exhaust discharges seawater	Some flow reaches that outlet	Adequate cooling everywhere or suitability of the cue for another installation
Stable idle and familiar sound	A useful current baseline	Safe performance under load or absence of a concealed leak

Use a controlled start window

The berth is still secure and the crew can observe before propulsion is needed.

1. Panel
Watch the complete lamp, audible alarm and instrument sequence rather than looking after it has finished.
2. Outlet
Check the installation's expected cooling/exhaust cue from a safe position.
3. Engine
Compare idle, sound, vibration, smell and leaks with the known baseline.
4. Commit
Select gear or depart only after critical cues are resolved and a safe abort remains available.

Sense check: The best place to reject an unexplained warning is usually before the vessel depends on propulsion.

Common mistake or limitation

Looking only at the panel after the self-test and missing whether a warning ever illuminated or cleared correctly.
Assuming every marine engine must show exhaust water or that visible water proves the cooling system is safe.
Increasing rpm or leaving the berth with an unresolved critical warning because the engine sounds normal.

Recap

Treat the first minute as a live verification step, not idle waiting time.
Use installation-specific panel and cooling cues.
Stop for unresolved critical evidence before commitment where the vessel situation permits.

Optional quick check

Section 2 of 8

A wet-exhaust engine starts and discharges water, but its oil-pressure warning remains active. Which cue governs the decision?

Previous Continue

Lesson 3 of 8

Fuel and Water Separator

What you will learn

Inspect the low-pressure fuel path and separator without confusing visible fuel with clean delivery or turning an observation into an unsafe intervention.

A separator bowl can reveal water, sediment, cloudiness, leakage or a level change before the fine filter or injection equipment is affected, but the exact inspection and draining procedure is installation-specific.

Trace the installed low-pressure path from tank and shut-off valve to the primary separator, lift pump and engine filter. Identify which bowl or drain is actually being inspected and whether it is clear, opaque, fitted with a water sensor or inaccessible without tools. Fuel in one bowl proves only fuel at that point; it does not prove an open downstream path, an unblocked fine filter or correct injection.

Compare the bowl with its known clean state. A distinct water layer, sediment, dark contamination, cloudiness, microbial debris, a falling or unusually empty bowl, damp fittings or diesel smell all need explanation. Do not map colour alone to one cause. Recent refuelling, rough water, filter work and tank history change the evidence and should be recorded.

Observation is not automatic permission to drain. Use the exact filter instructions, fuel isolation, ignition-source control, ventilation, absorbent material, a suitable container and spill/disposal plan. Opening the wrong drain or poor reassembly can introduce air, cause a leak or contaminate the bilge. High-pressure injection equipment remains outside a daily visual check.

Worked example

After rough weather, a previously clear separator shows a lower clear layer and dark particles while the engine has not yet been started.

1Preserve and record the observation; rough motion may have moved water or sediment from the tank into the pickup.
2Do not rely on one drain as proof the tank, filters and downstream path are clean.
3Use the filter and engine procedures, spill/fire controls and competence boundary to decide whether controlled service and bleeding are appropriate or qualified help is required.

Sense check: The bowl is an early warning and sampling point, not a complete fuel-quality certificate.

Fuel and Water Separator
Separator observation	Supported conclusion	Safe boundary
Distinct lower water layer	Water has reached this collection point	Investigate source and use the exact drain/service procedure
Sediment or dark debris	Contamination is present at this point	Do not assume one quick drain resolves the tank and filters
Damp union or diesel smell	A leak or residue needs distinction	Control ignition sources and do not tighten a live system casually
Clean-looking full bowl	No visible contamination in that view	Downstream flow, filter capacity and air-free injection remain unproved

Report the bowl, not a guessed cause

A crew member needs to describe the pre-start fuel check to the skipper.

1. Locate
Name the actual primary separator and its normal appearance.
2. Describe
Report layer, debris, cloudiness, level, dampness and smell without assigning a favourite fault.
3. Context
Add recent refuelling, rough water, maintenance and prior contamination history.
4. Control
Agree the manual-defined isolation, spill plan, bleeding requirement and release check before opening anything.

Sense check: 'A clear lower layer is visible' is stronger evidence than 'the fuel bug has returned'.

Common mistake or limitation

Calling every dark speck microbial growth or every cloudy bowl water without further evidence.
Draining into the bilge or opening a filter without fuel isolation, spill control and a reseal/bleed plan.
Assuming a full transparent bowl proves the fine filter, injection supply and tank contents are clean.

Recap

Use the separator as one observation point in a larger fuel path.
Describe the visible evidence and operating context before naming a cause.
Service only by the exact procedure, with fire, spill, air-entry and release controls.

Optional quick check

Section 3 of 8

A clean-looking separator bowl most directly confirms what?

Previous Continue

Lesson 4 of 8

Underway Monitoring

What you will learn

Detect meaningful changes under load, protect control of the vessel first and respond before a trend becomes a critical failure.

Daily checking continues after departure because load, heat and motion reveal faults that a cold inspection and idle run cannot. The learner's job is to notice change, rank its urgency and preserve a safe manoeuvring margin.

Establish an early under-load baseline at a known operating state: panel indications, engine note, vibration, response, visible discharge where relevant, exhaust appearance and smell. Scan again after a change in rpm, sea state, gear load or recent maintenance. A single number without the engine manual and the normal trend may be less useful than a clear change under comparable conditions.

Classify the cue before acting. A critical alarm, rapid temperature rise, oil-pressure warning, major leak, smoke or exhaust entering accommodation, or severe vibration can justify an immediate load reduction or stop as vessel safety permits. A small but repeatable change may allow a controlled return or closer monitoring, but it still needs a trigger for escalation. The navigation and traffic situation always remains part of the engine decision.

Avoid normalising drift. A belt squeal that happens every departure, a slowly weakening wet-exhaust discharge, repeated coolant loss or a diesel smell is not made safe by familiarity. Log time, engine hours, rpm/load, sea state, cue, action and result so maintenance can distinguish a trend from a one-off impression.

Worked example

Ten minutes after departure the wet-exhaust discharge looks weaker than at start and coolant temperature is rising steadily, but no alarm has yet sounded.

1Keep a safe navigation and traffic margin, compare the change at a controlled load and do not wait for an alarm as the first action trigger.
2Reduce load or stop as the vessel situation and manual permit, preserving the discharge and temperature timeline.
3Check only accessible, isolated operator points and do not open a hot pressurised cap; use the manual or qualified help before release.

Sense check: Two related adverse trends under load are stronger evidence than the absence of an alarm.

Underway Monitoring
Change under load	Immediate priority	Evidence to preserve
Critical oil/temperature alarm	Control vessel; reduce load or stop as safety and manual require	Panel sequence, load, time, level/leak and recent work
Wet-exhaust discharge weakens	Compare safely; prepare to unload/stop before overheating	Previous discharge, strainer/valve state, rpm and sea conditions
New diesel or exhaust smell	Protect crew, ventilate/stop as appropriate and locate safely	Where first noticed, wind/ventilation, visible leak or exhaust route
New vibration after gear engagement	Reduce demand and avoid further damage or loss of control	Neutral/engaged difference, rpm band, debris/impact history

Brief a change, not an opinion

A crew member sees something different while the skipper is conning the vessel.

1. Cue
Name what changed: indication, sound, smell, vibration, leak, smoke or discharge.
2. Condition
Add load, rpm, time, sea state and what happened immediately before it.
3. Trend
State whether it is stable, worsening, intermittent or restored after a controlled change.
4. Trigger
Agree the next load reduction, stop, diversion or assistance threshold while margin remains.

Sense check: 'Temperature has risen from its usual position for six minutes at the same load' is actionable; 'it feels hot' is not enough.

Common mistake or limitation

Waiting for an alarm even though two independent cues are already worsening.
Opening the engine space, reaching near moving parts or abandoning the helm in a constrained situation to investigate immediately.
Treating a recurring smell, squeal or fluid loss as normal because the engine has completed previous trips.

Recap

Load and heat expose faults that a cold or idle check cannot.
Protect vessel control, then classify and trend the cue.
Set action triggers early and preserve the evidence for maintenance.

Optional quick check

Section 4 of 8

At unchanged load, wet-exhaust discharge weakens and coolant temperature rises steadily. What is the strongest response?

Previous Continue

Lesson 5 of 8

Oil, Coolant and Transmission Baselines

What you will learn

Measure engine oil, coolant and transmission lubricant under the correct conditions and interpret level, condition and trend as separate evidence.

A dipstick or reservoir is only useful when the learner knows which system it belongs to, how the manual says to measure it and how today's result compares with prior checks.

Identify each fluid point physically and in the current manual. Engine oil, marine gearbox oil and saildrive lubricant can have different dipstick seating, thread, temperature and wait requirements. The boat's attitude can change a narrow sump reading. Use the specified lubricant and avoid topping above the upper mark; too much is not a reserve of safety.

Check closed-circuit coolant only by the installed safe procedure, normally when cool. A reservoir level may rise while hot and return as the system cools. A low reservoir, staining, crusting, sweet smell or recurring top-up need calls for investigation. Never open a hot pressurised filler to settle a checklist question.

Separate level, condition and trend. Milky or emulsified oil, unexpected rise, metal debris, burnt smell, repeated coolant loss or a new colour change can be significant even when the level sits within marks. Do not diagnose the internal cause from appearance alone; preserve a sample or photograph where useful and escalate beyond the operator boundary.

Worked example

After comparable cold checks, the coolant reservoir has moved from its normal mark to near minimum twice in three trips, with no obvious puddle.

1Confirm the same cool condition and correct reservoir are being compared; retain the dated readings.
2Inspect accessible cold hoses, clamps, stains and tray evidence without assuming no puddle means no loss.
3Do not repeatedly top up and erase the trend; use the exact manual and competent assistance before relying on the engine.

Sense check: A repeated comparable loss is evidence even when a single dramatic leak is not visible.

Oil, Coolant and Transmission Baselines
Observation	Question answered	Question still open
Engine oil inside marks	Stored level under this measurement condition	Running pressure, consumption cause or internal condition
Coolant reservoir at cold mark	Stored reservoir level when cool	Raw-water flow and heat rejection under load
Gearbox oil inside range	Stored transmission lubricant level	Clutch engagement, seal integrity under load or propeller condition
Level changed since last check	A trend exists if conditions match	Leak, consumption, transfer or reading error requires distinction

Make the measurement reproducible

Two crew members obtain different oil readings from the same engine.

1. System
Confirm they used the engine-oil dipstick rather than the gearbox or saildrive point.
2. Condition
Match boat attitude, engine temperature, wait time, dipstick cleaning and seating to the manual.
3. Repeat
Take a second controlled reading instead of averaging unlike methods.
4. Record
Log the comparable result and any condition or appearance change.

Sense check: Repeatability is more useful than false precision from two different methods.

Common mistake or limitation

Confusing engine, gearbox and saildrive lubricant points or using the same dipstick method for all three.
Opening a hot coolant cap or interpreting the hot reservoir level as the cold baseline.
Adding fluid to the upper mark before investigating why a comparable level changed.

Recap

Identify the system and reproduce the manual-defined measurement condition.
Interpret level, appearance and trend separately.
Investigate comparable change rather than hiding it with automatic top-up.

Optional quick check

Section 5 of 8

Two oil readings disagree. What should happen before averaging them?

Previous Continue

Lesson 6 of 8

Belts, Hoses, Mounts and Engine Space

What you will learn

Inspect visible mechanical condition while isolated and distinguish a useful warning sign from an unsafe running adjustment or unsupported diagnosis.

Belts, hoses, clamps, mounts, wiring and the engine tray form one condition scan. Their value comes from comparison, isolation and early action, not from touching moving machinery.

With the engine stopped, prevented from unexpected start and cool enough to inspect, look along the complete accessible belt path. Cracks, missing material, glazing, black dust, fraying, contamination, pulley misalignment or a new squeal are evidence. Exact tension and deflection are model-specific; pressing a running belt, levering an alternator casually or tightening without the procedure can cause injury or damage.

Trace accessible hoses and connections for chafe, bulges, hardening, soft spots, cracking, staining, loose support and clamp movement. Look at mounts, fasteners, wiring supports, guards and exhaust components for movement or fresh witness marks. Do not put hands into a running space to find vibration or a leak, and never use a hand to search for high-pressure fuel spray.

Keep the tray and bilge clean enough to show change, but do not confuse cleaning with repair. Identify fluid by colour, smell, location and system context only as preliminary evidence; contain it, protect against fire and pollution, and preserve the likely origin before wiping everything away. Tools, rags and loose covers must be removed and guards restored before start.

Worked example

The alternator belt has new black dust beneath one pulley but no visible crack and the engine has not yet started.

1Record the dust pattern and compare with the prior clean baseline; do not assume appearance alone identifies tension or alignment cause.
2Keep the engine isolated and use the exact manual's inspection/tension procedure, checking contamination and pulley evidence within competence.
3Restore guards and tools, then define what controlled after-start observation would be required before release.

Sense check: No crack does not cancel new dust, and new dust does not authorise an improvised adjustment.

Belts, Hoses, Mounts and Engine Space
Cue	Useful interpretation	Unsafe shortcut
Black belt dust	Slip, wear, misalignment or contamination requires distinction	Tighten by feel while running
Hose staining at clamp	Past or current seepage needs a clean/dry comparison	Over-tighten without checking hose and fitting
Fresh mount witness mark	Relative movement may have occurred	Run with the guard removed to watch closely
New fluid in tray	A system has changed or spilled	Wipe it away before recording source and amount

Scan for a change path

A small amount of fresh fluid and a new witness mark appear after recent service.

1. Preserve
Photograph or note amount, colour and location before cleaning.
2. Trace
Work upward and along accessible hoses, unions, mounts and recently disturbed areas without entering a hazard.
3. Boundary
Stop at hot, pressurised, moving, high-current or high-pressure fuel work outside competence.
4. Release
Require dry/secure evidence, restored guards and a controlled recheck rather than a tidy tray alone.

Sense check: A clean tray after wiping proves only that the fluid was removed.

Common mistake or limitation

Testing belt tension, feeling vibration or tracing a leak with the engine running and guards open.
Assuming belt dust always means slackness or that tightening is safe without checking alignment, contamination and specification.
Cleaning the tray before preserving the location, amount and likely route of a new fluid change.

Recap

Isolate first and inspect the whole accessible condition path.
Treat visible cues as evidence to distinguish, not instant component diagnoses.
Restore guards, tools and loose items before any controlled run check.

Optional quick check

Section 6 of 8

New black dust appears below a belt with no visible crack. What follows?

Previous Continue

Lesson 7 of 8

Post-Run Check and Trend Log

What you will learn

Use the controlled post-run period to capture leaks, heat, smell, fluid use and operating changes before the evidence disappears.

The return check closes the loop. It records what changed under load, restores the installation to its required state and gives the next start a reliable baseline.

After securing the vessel and stopping by the manual, watch the panel and engine rundown, then allow hot and moving hazards to settle before inspection. Note new drips, staining, coolant or fuel smell, belt debris, loose items, abnormal residual heat and changes in the tray or bilge. Do not open a hot coolant cap or reach into machinery that can restart or continue rotating.

Restore installation-specific controls deliberately. Some boats require a seawater intake to be closed when unattended; others have different procedures or shared systems. Record the position and use a clear reminder so the next operator does not start against a closed valve. Recheck tools, guards, filler caps, dipsticks, filter drains and absorbent materials after any intervention.

Log engine hours, approximate load/duration, relevant sea state, fuel or coolant additions, separator findings, alarms, sound/vibration/smell changes, action and result. A short consistent record can reveal oil or coolant consumption, repeat contamination, belt deterioration and temperature drift. Logging is not a substitute for repair: attach a clear status and next action.

Worked example

The engine completed a trip without an alarm, but the post-run tray contains two teaspoons of coolant-coloured fluid and the log shows a small coolant top-up on the previous trip.

1Record location, approximate amount, operating duration and the prior top-up before cleaning the tray.
2Allow the engine to cool and inspect accessible reservoir, hose, clamp and staining evidence without opening a hot system.
3Mark the issue unresolved and investigate before the next start; absence of an alarm does not release a repeat loss trend.

Sense check: Two small connected observations across trips can be more important than one alarm-free run.

Post-Run Check and Trend Log
Log field	Why it matters	Weak substitute
Engine hours and load/duration	Makes trends comparable	'Ran for a while'
Cue and condition	Links smell, vibration, temperature or leak to operating state	'Engine seemed odd'
Fluid added or removed	Exposes consumption and prevents duplicate action	Topping up without quantity or reason
Status and next action	Stops an unresolved issue being handed over as normal	A note with no release decision

Hand the next operator a state, not a story

A different skipper will use the boat tomorrow.

1. Record
State conditions, exact cue, amount and location while memory is fresh.
2. Restore
List valves, guards, caps and controls returned to their required unattended state.
3. Status
Mark cleared, monitor with a trigger, or do not start pending investigation.
4. Handover
Point to the log, manual and physical location rather than relying on a casual message.

Sense check: 'Keep an eye on it' is not a release condition unless the cue, trigger and action are defined.

Common mistake or limitation

Ending the routine when the engine stops and losing evidence that appears only after a loaded run.
Closing or leaving open a seawater valve by habit without the installed procedure and a clear next-start reminder.
Recording an observation without quantity, conditions, status or the action required before reuse.

Recap

Close the daily-check loop after the loaded run.
Restore the installation deliberately and preserve evidence before cleaning.
Use a comparable log with an explicit unresolved or released state.

Optional quick check

Section 7 of 8

Why record a small repeat coolant loss even without an alarm?

Previous Continue

Lesson 8 of 8

Departure Decision and Handover

What you will learn

Turn pre-start, after-start and under-load evidence into an explicit go, monitor, stop or escalate decision with a defined release condition.

The purpose of the routine is not a completed checklist; it is a defensible decision about whether propulsion can be relied on for the intended next phase and what remains unresolved.

Combine evidence by system and consequence, not by majority vote. A clean separator, correct cold oil level and smooth idle do not cancel a persistent oil-pressure alarm. A familiar engine note does not cancel missing wet-exhaust discharge on an installation that requires it. Independent critical gates remain controlling until the indication and underlying condition are credibly resolved.

Use four clear outcomes. 'Go' means expected checks, guards and controls are restored and no material exception remains. 'Monitor' requires a non-critical, understood cue, comparable baseline, explicit trigger and safe fallback. 'Stop/do not depart' applies to an unresolved critical alarm, missing required cooling cue, significant leak, unsafe machinery state or loss of dependable propulsion. 'Escalate' applies when diagnosis or repair exceeds the manual, tools, conditions or competence.

Match the release to the intended use. A successful idle restart does not prove loaded propulsion for a confined departure. A wiped tray does not prove the leak has stopped. Where the manual and vessel situation permit, require the appropriate controlled recheck, normal indications, no repeat leak, restored guards and retained abort margin. Record who made the decision and what must happen next.

Worked example

After a separator drain, the engine restarts and idles normally. A fuel smell remains and the filter union is damp, but no drip is seen.

1Do not use the successful start as release; it confirms combustion, not a sealed fuel system.
2Stop, control ignition and spill risk, and inspect/reseal only by the filter procedure and competence boundary.
3Require a dry union through the specified prime/start and controlled recheck, with tools removed and no recurring smell, before departure.

Sense check: A damp fuel union is a critical unresolved exception even when several other checks pass.

Departure Decision and Handover
Outcome	Minimum evidence	Example
Go	Expected sequence, restored installation, no material exception	Normal pre-start, start and controlled load cues
Monitor	Non-critical understood cue, trend trigger and safe fallback	Stable minor change with agreed return/stop threshold
Stop / do not depart	Critical gate unresolved or dependable propulsion not established	Oil alarm remains or required wet-exhaust discharge absent
Escalate	Procedure, hazard or uncertainty exceeds competence	Hot pressure system, high-pressure fuel or unresolved recurring leak

Give the skipper a decision-ready handover

The checker is not the person deciding whether to leave a constrained berth.

1. State
Report pre-start, start and any controlled-load result in sequence.
2. Exception
Name each unresolved cue and the system/consequence it affects.
3. Outcome
Recommend go, monitor with trigger, stop/do not depart or escalate.
4. Release
State the exact evidence still required before greater load or commitment.

Sense check: A signed checklist with an unexplained critical exception is not a safe handover.

Common mistake or limitation

Counting passed items and allowing the majority to overrule one unresolved critical gate.
Using 'monitor' without a defined cue, threshold, action and navigational fallback.
Declaring a repair complete after one restart when the original leak, alarm or loaded condition has not been reproduced safely.

Recap

The outcome is a propulsion-readiness decision, not checklist completion.
Critical unresolved evidence controls the decision.
Define and record the release condition for the intended next phase.

Optional quick check

Section 8 of 8

Seven routine checks pass, but a fuel union remains damp after service. What is the decision?

Previous Continue to Practise

Lesson previewChecks Before Starting1 section shown

Preview lesson

Checks Before Starting

What you will learn

Build a safe, repeatable pre-start sequence that compares the engine with its own known baseline instead of merely ticking a list.

Daily check decision board

Separate the observation from the departure decision

Select a case. The phase, evidence limit, safe decision and release condition are all available as text and do not depend on colour.

COLDPre-start

LIVEAfter start

LOADUnderway

LOGPost-run

The check closes only after the post-run evidence becomes the next reliable pre-start baseline.

1 · Observed

The cold oil level is inside the marks but lower than the comparable logged baseline, with one fresh drop in the tray.

2 · This supports

Stored oil remains within the marked range under this check condition, and a real change may have occurred since the last comparable reading.

3 · This does not prove

The range does not prove running pressure, explain the downward trend or cancel the fresh leak evidence.

4 · Safe decision

Preserve the reading and drop location. Confirm the manual-defined method, then investigate accessible isolated areas before starting.

5 · Release

Comparable level is understood, the source is credibly resolved, the tray remains dry and the manual-defined start verification is available.

Select a check case and separate what the observation supports from what still needs a safe release decision.

Worked example

The cold oil level is between the marks but is visibly lower than the photograph and log from the previous two checks; a fresh amber drop is present beneath the engine.

1Confirm the boat, dipstick seating and wait condition match the manual-defined baseline before comparing readings.
2Treat the falling trend and fresh drop as linked evidence to investigate; do not top up first and erase the change.
3Trace only accessible, isolated areas permitted by the manual, contain the fluid and decide whether competent help is needed before start.

Sense check: 'Inside the marks' answers one level question. It does not explain a new downward trend and leak evidence.

Checks Before Starting
Pre-start point	Evidence to establish	What it does not prove
Engine oil	Manual-defined cold or settled reading within range and consistent with trend	Running oil pressure or absence of an internal fault
Coolant	Cold reservoir or filler check by the installed procedure	Raw-water flow, heat-transfer performance or a leak-free loaded run
Seawater path	Correct valve/strainer state for this installation	Pump delivery or wet-exhaust discharge after start
Tray/bilge	Known baseline with no unexplained new fluid	That every hose, seal or system remains sound under load

Build a personal normal card

A new skipper needs a routine that another crew member can repeat and report accurately.

1. Map
Use the current manuals to locate the real dipsticks, reservoirs, strainers, valves, filters and isolation controls.
2. Baseline
Record cold levels, tray appearance, belt condition and normal control positions without inventing universal limits.
3. Compare
Ask what changed since the last reliable check, service or run.
4. Decide
Start only when the observed state and unresolved exceptions fit the manual and voyage plan.

Sense check: A checklist becomes useful when two competent people mean the same thing by 'normal'.

Common mistake or limitation

Opening a hot pressurised coolant cap or reaching near belts because the checklist says 'check coolant' or 'check belt'.
Using a generic online layout instead of identifying the actual engine, gearbox, saildrive and cooling arrangement.
Calling any reading between two marks normal without comparing measurement conditions and recent trend.

Recap

Control the machinery state before collecting evidence.
Use one installation-specific route and one repeatable measurement condition.
Compare with a recorded baseline and resolve meaningful changes before start.

Optional quick check

Section 1 of 1

The cold oil reading is within the marks but lower than yesterday and there is a fresh drop below the engine. What is the best interpretation?

Continue to Practise

Lesson routeChecks Before Starting0/8 read

Lesson 1 of 8

Checks Before Starting

What you will learn

Build a safe, repeatable pre-start sequence that compares the engine with its own known baseline instead of merely ticking a list.

Daily check decision board

Separate the observation from the departure decision

Select a case. The phase, evidence limit, safe decision and release condition are all available as text and do not depend on colour.

COLDPre-start

LIVEAfter start

LOADUnderway

LOGPost-run

The check closes only after the post-run evidence becomes the next reliable pre-start baseline.

1 · Observed

The cold oil level is inside the marks but lower than the comparable logged baseline, with one fresh drop in the tray.

2 · This supports

Stored oil remains within the marked range under this check condition, and a real change may have occurred since the last comparable reading.

3 · This does not prove

The range does not prove running pressure, explain the downward trend or cancel the fresh leak evidence.

4 · Safe decision

Preserve the reading and drop location. Confirm the manual-defined method, then investigate accessible isolated areas before starting.

5 · Release

Comparable level is understood, the source is credibly resolved, the tray remains dry and the manual-defined start verification is available.

Select a check case and separate what the observation supports from what still needs a safe release decision.

Worked example

The cold oil level is between the marks but is visibly lower than the photograph and log from the previous two checks; a fresh amber drop is present beneath the engine.

1Confirm the boat, dipstick seating and wait condition match the manual-defined baseline before comparing readings.
2Treat the falling trend and fresh drop as linked evidence to investigate; do not top up first and erase the change.
3Trace only accessible, isolated areas permitted by the manual, contain the fluid and decide whether competent help is needed before start.

Sense check: 'Inside the marks' answers one level question. It does not explain a new downward trend and leak evidence.

Checks Before Starting
Pre-start point	Evidence to establish	What it does not prove
Engine oil	Manual-defined cold or settled reading within range and consistent with trend	Running oil pressure or absence of an internal fault
Coolant	Cold reservoir or filler check by the installed procedure	Raw-water flow, heat-transfer performance or a leak-free loaded run
Seawater path	Correct valve/strainer state for this installation	Pump delivery or wet-exhaust discharge after start
Tray/bilge	Known baseline with no unexplained new fluid	That every hose, seal or system remains sound under load

Build a personal normal card

A new skipper needs a routine that another crew member can repeat and report accurately.

1. Map
Use the current manuals to locate the real dipsticks, reservoirs, strainers, valves, filters and isolation controls.
2. Baseline
Record cold levels, tray appearance, belt condition and normal control positions without inventing universal limits.
3. Compare
Ask what changed since the last reliable check, service or run.
4. Decide
Start only when the observed state and unresolved exceptions fit the manual and voyage plan.

Sense check: A checklist becomes useful when two competent people mean the same thing by 'normal'.

Common mistake or limitation

Opening a hot pressurised coolant cap or reaching near belts because the checklist says 'check coolant' or 'check belt'.
Using a generic online layout instead of identifying the actual engine, gearbox, saildrive and cooling arrangement.
Calling any reading between two marks normal without comparing measurement conditions and recent trend.

Recap

Control the machinery state before collecting evidence.
Use one installation-specific route and one repeatable measurement condition.
Compare with a recorded baseline and resolve meaningful changes before start.

Optional quick check

Section 1 of 8

The cold oil reading is within the marks but lower than yesterday and there is a fresh drop below the engine. What is the best interpretation?

Continue

Lesson 2 of 8

After Starting

What you will learn

Use the first controlled minute after start to verify alarms, lubrication, charging, cooling and abnormal sound before committing the vessel.

Starting is not the end of the check. It creates the first live evidence that oil-pressure indication, panel behaviour, charging, cooling and engine response are credible enough to continue.

Worked example

The engine starts smoothly and wet-exhaust water appears, but the oil-pressure warning stays on beyond its normal manual-defined clearing interval.

1Separate the cues: combustion and some seawater discharge are present; safe lubrication is not confirmed.
2Stop as the vessel situation permits rather than increasing rpm to make the warning disappear.
3Preserve the panel sequence and use the exact manual or competent assistance to distinguish indication from an underlying pressure problem before restart.

Sense check: Cooling evidence cannot cancel an unresolved lubrication warning.

After Starting
After-start cue	Supports	Does not establish
Oil-pressure warning clears normally	The monitored warning circuit no longer reports low pressure	That oil level, pressure sender and every lubricated part are fault-free
Charging indication becomes normal	Expected alternator/charging response at that moment	Battery capacity, belt condition or all electrical connections
Wet exhaust discharges seawater	Some flow reaches that outlet	Adequate cooling everywhere or suitability of the cue for another installation
Stable idle and familiar sound	A useful current baseline	Safe performance under load or absence of a concealed leak

Use a controlled start window

The berth is still secure and the crew can observe before propulsion is needed.

1. Panel
Watch the complete lamp, audible alarm and instrument sequence rather than looking after it has finished.
2. Outlet
Check the installation's expected cooling/exhaust cue from a safe position.
3. Engine
Compare idle, sound, vibration, smell and leaks with the known baseline.
4. Commit
Select gear or depart only after critical cues are resolved and a safe abort remains available.

Sense check: The best place to reject an unexplained warning is usually before the vessel depends on propulsion.

Common mistake or limitation

Looking only at the panel after the self-test and missing whether a warning ever illuminated or cleared correctly.
Assuming every marine engine must show exhaust water or that visible water proves the cooling system is safe.
Increasing rpm or leaving the berth with an unresolved critical warning because the engine sounds normal.

Recap

Treat the first minute as a live verification step, not idle waiting time.
Use installation-specific panel and cooling cues.
Stop for unresolved critical evidence before commitment where the vessel situation permits.

Optional quick check

Section 2 of 8

A wet-exhaust engine starts and discharges water, but its oil-pressure warning remains active. Which cue governs the decision?

Previous Continue

Lesson 3 of 8

Fuel and Water Separator

What you will learn

Inspect the low-pressure fuel path and separator without confusing visible fuel with clean delivery or turning an observation into an unsafe intervention.

Worked example

After rough weather, a previously clear separator shows a lower clear layer and dark particles while the engine has not yet been started.

1Preserve and record the observation; rough motion may have moved water or sediment from the tank into the pickup.
2Do not rely on one drain as proof the tank, filters and downstream path are clean.
3Use the filter and engine procedures, spill/fire controls and competence boundary to decide whether controlled service and bleeding are appropriate or qualified help is required.

Sense check: The bowl is an early warning and sampling point, not a complete fuel-quality certificate.

Fuel and Water Separator
Separator observation	Supported conclusion	Safe boundary
Distinct lower water layer	Water has reached this collection point	Investigate source and use the exact drain/service procedure
Sediment or dark debris	Contamination is present at this point	Do not assume one quick drain resolves the tank and filters
Damp union or diesel smell	A leak or residue needs distinction	Control ignition sources and do not tighten a live system casually
Clean-looking full bowl	No visible contamination in that view	Downstream flow, filter capacity and air-free injection remain unproved

Report the bowl, not a guessed cause

A crew member needs to describe the pre-start fuel check to the skipper.

1. Locate
Name the actual primary separator and its normal appearance.
2. Describe
Report layer, debris, cloudiness, level, dampness and smell without assigning a favourite fault.
3. Context
Add recent refuelling, rough water, maintenance and prior contamination history.
4. Control
Agree the manual-defined isolation, spill plan, bleeding requirement and release check before opening anything.

Sense check: 'A clear lower layer is visible' is stronger evidence than 'the fuel bug has returned'.

Common mistake or limitation

Calling every dark speck microbial growth or every cloudy bowl water without further evidence.
Draining into the bilge or opening a filter without fuel isolation, spill control and a reseal/bleed plan.
Assuming a full transparent bowl proves the fine filter, injection supply and tank contents are clean.

Recap

Use the separator as one observation point in a larger fuel path.
Describe the visible evidence and operating context before naming a cause.
Service only by the exact procedure, with fire, spill, air-entry and release controls.

Optional quick check

Section 3 of 8

A clean-looking separator bowl most directly confirms what?

Previous Continue

Lesson 4 of 8

Underway Monitoring

What you will learn

Detect meaningful changes under load, protect control of the vessel first and respond before a trend becomes a critical failure.

Worked example

Ten minutes after departure the wet-exhaust discharge looks weaker than at start and coolant temperature is rising steadily, but no alarm has yet sounded.

1Keep a safe navigation and traffic margin, compare the change at a controlled load and do not wait for an alarm as the first action trigger.
2Reduce load or stop as the vessel situation and manual permit, preserving the discharge and temperature timeline.
3Check only accessible, isolated operator points and do not open a hot pressurised cap; use the manual or qualified help before release.

Sense check: Two related adverse trends under load are stronger evidence than the absence of an alarm.

Underway Monitoring
Change under load	Immediate priority	Evidence to preserve
Critical oil/temperature alarm	Control vessel; reduce load or stop as safety and manual require	Panel sequence, load, time, level/leak and recent work
Wet-exhaust discharge weakens	Compare safely; prepare to unload/stop before overheating	Previous discharge, strainer/valve state, rpm and sea conditions
New diesel or exhaust smell	Protect crew, ventilate/stop as appropriate and locate safely	Where first noticed, wind/ventilation, visible leak or exhaust route
New vibration after gear engagement	Reduce demand and avoid further damage or loss of control	Neutral/engaged difference, rpm band, debris/impact history

Brief a change, not an opinion

A crew member sees something different while the skipper is conning the vessel.

1. Cue
Name what changed: indication, sound, smell, vibration, leak, smoke or discharge.
2. Condition
Add load, rpm, time, sea state and what happened immediately before it.
3. Trend
State whether it is stable, worsening, intermittent or restored after a controlled change.
4. Trigger
Agree the next load reduction, stop, diversion or assistance threshold while margin remains.

Sense check: 'Temperature has risen from its usual position for six minutes at the same load' is actionable; 'it feels hot' is not enough.

Common mistake or limitation

Waiting for an alarm even though two independent cues are already worsening.
Opening the engine space, reaching near moving parts or abandoning the helm in a constrained situation to investigate immediately.
Treating a recurring smell, squeal or fluid loss as normal because the engine has completed previous trips.

Recap

Load and heat expose faults that a cold or idle check cannot.
Protect vessel control, then classify and trend the cue.
Set action triggers early and preserve the evidence for maintenance.

Optional quick check

Section 4 of 8

At unchanged load, wet-exhaust discharge weakens and coolant temperature rises steadily. What is the strongest response?

Previous Continue

Lesson 5 of 8

Oil, Coolant and Transmission Baselines

What you will learn

Measure engine oil, coolant and transmission lubricant under the correct conditions and interpret level, condition and trend as separate evidence.

A dipstick or reservoir is only useful when the learner knows which system it belongs to, how the manual says to measure it and how today's result compares with prior checks.

Worked example

After comparable cold checks, the coolant reservoir has moved from its normal mark to near minimum twice in three trips, with no obvious puddle.

1Confirm the same cool condition and correct reservoir are being compared; retain the dated readings.
2Inspect accessible cold hoses, clamps, stains and tray evidence without assuming no puddle means no loss.
3Do not repeatedly top up and erase the trend; use the exact manual and competent assistance before relying on the engine.

Sense check: A repeated comparable loss is evidence even when a single dramatic leak is not visible.

Oil, Coolant and Transmission Baselines
Observation	Question answered	Question still open
Engine oil inside marks	Stored level under this measurement condition	Running pressure, consumption cause or internal condition
Coolant reservoir at cold mark	Stored reservoir level when cool	Raw-water flow and heat rejection under load
Gearbox oil inside range	Stored transmission lubricant level	Clutch engagement, seal integrity under load or propeller condition
Level changed since last check	A trend exists if conditions match	Leak, consumption, transfer or reading error requires distinction

Make the measurement reproducible

Two crew members obtain different oil readings from the same engine.

1. System
Confirm they used the engine-oil dipstick rather than the gearbox or saildrive point.
2. Condition
Match boat attitude, engine temperature, wait time, dipstick cleaning and seating to the manual.
3. Repeat
Take a second controlled reading instead of averaging unlike methods.
4. Record
Log the comparable result and any condition or appearance change.

Sense check: Repeatability is more useful than false precision from two different methods.

Common mistake or limitation

Confusing engine, gearbox and saildrive lubricant points or using the same dipstick method for all three.
Opening a hot coolant cap or interpreting the hot reservoir level as the cold baseline.
Adding fluid to the upper mark before investigating why a comparable level changed.

Recap

Identify the system and reproduce the manual-defined measurement condition.
Interpret level, appearance and trend separately.
Investigate comparable change rather than hiding it with automatic top-up.

Optional quick check

Section 5 of 8

Two oil readings disagree. What should happen before averaging them?

Previous Continue

Lesson 6 of 8

Belts, Hoses, Mounts and Engine Space

What you will learn

Inspect visible mechanical condition while isolated and distinguish a useful warning sign from an unsafe running adjustment or unsupported diagnosis.

Belts, hoses, clamps, mounts, wiring and the engine tray form one condition scan. Their value comes from comparison, isolation and early action, not from touching moving machinery.

Worked example

The alternator belt has new black dust beneath one pulley but no visible crack and the engine has not yet started.

1Record the dust pattern and compare with the prior clean baseline; do not assume appearance alone identifies tension or alignment cause.
2Keep the engine isolated and use the exact manual's inspection/tension procedure, checking contamination and pulley evidence within competence.
3Restore guards and tools, then define what controlled after-start observation would be required before release.

Sense check: No crack does not cancel new dust, and new dust does not authorise an improvised adjustment.

Belts, Hoses, Mounts and Engine Space
Cue	Useful interpretation	Unsafe shortcut
Black belt dust	Slip, wear, misalignment or contamination requires distinction	Tighten by feel while running
Hose staining at clamp	Past or current seepage needs a clean/dry comparison	Over-tighten without checking hose and fitting
Fresh mount witness mark	Relative movement may have occurred	Run with the guard removed to watch closely
New fluid in tray	A system has changed or spilled	Wipe it away before recording source and amount

Scan for a change path

A small amount of fresh fluid and a new witness mark appear after recent service.

1. Preserve
Photograph or note amount, colour and location before cleaning.
2. Trace
Work upward and along accessible hoses, unions, mounts and recently disturbed areas without entering a hazard.
3. Boundary
Stop at hot, pressurised, moving, high-current or high-pressure fuel work outside competence.
4. Release
Require dry/secure evidence, restored guards and a controlled recheck rather than a tidy tray alone.

Sense check: A clean tray after wiping proves only that the fluid was removed.

Common mistake or limitation

Testing belt tension, feeling vibration or tracing a leak with the engine running and guards open.
Assuming belt dust always means slackness or that tightening is safe without checking alignment, contamination and specification.
Cleaning the tray before preserving the location, amount and likely route of a new fluid change.

Recap

Isolate first and inspect the whole accessible condition path.
Treat visible cues as evidence to distinguish, not instant component diagnoses.
Restore guards, tools and loose items before any controlled run check.

Optional quick check

Section 6 of 8

New black dust appears below a belt with no visible crack. What follows?

Previous Continue

Lesson 7 of 8

Post-Run Check and Trend Log

What you will learn

Use the controlled post-run period to capture leaks, heat, smell, fluid use and operating changes before the evidence disappears.

The return check closes the loop. It records what changed under load, restores the installation to its required state and gives the next start a reliable baseline.

Worked example

The engine completed a trip without an alarm, but the post-run tray contains two teaspoons of coolant-coloured fluid and the log shows a small coolant top-up on the previous trip.

1Record location, approximate amount, operating duration and the prior top-up before cleaning the tray.
2Allow the engine to cool and inspect accessible reservoir, hose, clamp and staining evidence without opening a hot system.
3Mark the issue unresolved and investigate before the next start; absence of an alarm does not release a repeat loss trend.

Sense check: Two small connected observations across trips can be more important than one alarm-free run.

Post-Run Check and Trend Log
Log field	Why it matters	Weak substitute
Engine hours and load/duration	Makes trends comparable	'Ran for a while'
Cue and condition	Links smell, vibration, temperature or leak to operating state	'Engine seemed odd'
Fluid added or removed	Exposes consumption and prevents duplicate action	Topping up without quantity or reason
Status and next action	Stops an unresolved issue being handed over as normal	A note with no release decision

Hand the next operator a state, not a story

A different skipper will use the boat tomorrow.

1. Record
State conditions, exact cue, amount and location while memory is fresh.
2. Restore
List valves, guards, caps and controls returned to their required unattended state.
3. Status
Mark cleared, monitor with a trigger, or do not start pending investigation.
4. Handover
Point to the log, manual and physical location rather than relying on a casual message.

Sense check: 'Keep an eye on it' is not a release condition unless the cue, trigger and action are defined.

Common mistake or limitation

Ending the routine when the engine stops and losing evidence that appears only after a loaded run.
Closing or leaving open a seawater valve by habit without the installed procedure and a clear next-start reminder.
Recording an observation without quantity, conditions, status or the action required before reuse.

Recap

Close the daily-check loop after the loaded run.
Restore the installation deliberately and preserve evidence before cleaning.
Use a comparable log with an explicit unresolved or released state.

Optional quick check

Section 7 of 8

Why record a small repeat coolant loss even without an alarm?

Previous Continue

Lesson 8 of 8

Departure Decision and Handover

What you will learn

Turn pre-start, after-start and under-load evidence into an explicit go, monitor, stop or escalate decision with a defined release condition.

The purpose of the routine is not a completed checklist; it is a defensible decision about whether propulsion can be relied on for the intended next phase and what remains unresolved.

Worked example

After a separator drain, the engine restarts and idles normally. A fuel smell remains and the filter union is damp, but no drip is seen.

1Do not use the successful start as release; it confirms combustion, not a sealed fuel system.
2Stop, control ignition and spill risk, and inspect/reseal only by the filter procedure and competence boundary.
3Require a dry union through the specified prime/start and controlled recheck, with tools removed and no recurring smell, before departure.

Sense check: A damp fuel union is a critical unresolved exception even when several other checks pass.

Departure Decision and Handover
Outcome	Minimum evidence	Example
Go	Expected sequence, restored installation, no material exception	Normal pre-start, start and controlled load cues
Monitor	Non-critical understood cue, trend trigger and safe fallback	Stable minor change with agreed return/stop threshold
Stop / do not depart	Critical gate unresolved or dependable propulsion not established	Oil alarm remains or required wet-exhaust discharge absent
Escalate	Procedure, hazard or uncertainty exceeds competence	Hot pressure system, high-pressure fuel or unresolved recurring leak

Give the skipper a decision-ready handover

The checker is not the person deciding whether to leave a constrained berth.

1. State
Report pre-start, start and any controlled-load result in sequence.
2. Exception
Name each unresolved cue and the system/consequence it affects.
3. Outcome
Recommend go, monitor with trigger, stop/do not depart or escalate.
4. Release
State the exact evidence still required before greater load or commitment.

Sense check: A signed checklist with an unexplained critical exception is not a safe handover.

Common mistake or limitation

Counting passed items and allowing the majority to overrule one unresolved critical gate.
Using 'monitor' without a defined cue, threshold, action and navigational fallback.
Declaring a repair complete after one restart when the original leak, alarm or loaded condition has not been reproduced safely.

Recap

The outcome is a propulsion-readiness decision, not checklist completion.
Critical unresolved evidence controls the decision.
Define and record the release condition for the intended next phase.

Optional quick check

Section 8 of 8

Seven routine checks pass, but a fuel union remains damp after service. What is the decision?

Previous Continue to Practise