QUESTION 4.1.7

Echo sounder operation

Oil, Chemical, LPG, LNGBridge

What is being checked

The inspector is checking whether the echo sounder is configured and used as an independent depth and UKC-monitoring aid during landfall, coastal, pilotage and shallow-water navigation, with officers able to configure, cross-check, test and respond to failure of the actual equipment fitted.

Ready onboard

0/6 complete

PROCEDUREThe company procedure defines safe use, testing, limitations and failure response for echo sounder operation.CONFIGURATIONTransducer selection, draft offset, depth reference, range, gain, alarm and recording mode are set for the present draft and water depth.FUNCTION TESTRun the approved self-test, compare indicated depth with charted and calculated depth at a known position, verify paper or digital recording and test alarms.DEPTH REFERENCEThe bridge team knows whether displayed depth is below keel, below transducer or below surface.SHALLOW ALARMAlarm setting supports the passage-plan UKC and does not merely use a standing default.RECORDINGDepth trace or digital record is retained for critical approaches as required.

Practice questions

Answer aloud, then open the preparation point.

1What safety function does echo sounder operation provide?

The echo sounder is configured and used as an independent depth and ukc-monitoring aid during landfall, coastal, pilotage and shallow-water navigation.

2How is the complete function tested?

Run the approved self-test, compare indicated depth with charted and calculated depth at a known position, verify paper or digital recording and test alarms.

3What is its principal limitation?

Aeration, soft bottom, multiple echoes, transducer offset, excessive speed and steep seabed can produce weak or misleading depths.

4What is your response if it fails?

Reduce speed if required, use the alternate transducer or manual settings, compare charted depth, tide and position, call the Master and treat unreliable depth as a navigation limitation.

5Show the latest test and operational evidence.

Link the dated record to the actual unit, test method, result, defect response and restoration; a panel lamp test alone is not sufficient where the full signal path can be tested.

Where an observation may arise

PROCEDURE UNKNOWN

The responsible officer cannot explain safe use, limitations or failure response.

TEST INCOMPLETE

Testing does not prove the required operational function or remote indication.

OFFSET ERROR

Displayed reference is misunderstood or entered incorrectly.

ALARM DEFAULT

The shallow alarm does not correspond to the planned safe depth.

SWITCHED OFF

The unit is not used during a critical shallow-water leg.

Master's practical note

Reconcile one displayed depth with chart, tide, draft and transducer reference. A believable number can still be wrong by the vessel's draft if the offset is misunderstood.

Equipment boundary and references

Equipment boundary: Echo sounder is supporting evidence, not a substitute for calculated UKC or reliable positioning. Test and use must avoid damaging transducers and comply with maker instructions.

References

OCIMF SIRE 2.0 Question Library Part 1, Version 1.0, Question 4.1.7
SOLAS Chapter V regulation 19
IMO Resolution MSC.74(69), Annex 4
ICS Bridge Procedures Guide

Last reviewed: 2026-09-11