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Technical Service Guide
Underwater Pitometer Log, ADCP and Speed Log Renewal
Published
SVC Marine undertakes underwater inspection, repair and renewal work for pitometer-log pickups, acoustic Doppler current profiler (ADCP) heads and ship speed-log fittings in Vietnam. Send the equipment identification, vessel position and work window first. We define the hull-side task from the actual installation before proposing diver access, removal or replacement.
A pressure-type pitometer is one type of ship speed log; an ADCP commonly profiles water currents. The installed model determines the speed output and hull arrangement. This is a service worklist, not a record that all three systems were renewed on one vessel.
01
Identify the instrument and fault
SVC starts with the maker, model, drawings and the symptom reported by the bridge or engine room. A missing reading, unstable speed, blocked pickup, damaged transducer face or suspected leak needs a different inspection plan. We identify whether the concern is the external sensor, hull penetration, inboard cable or pressure line, processor, or displayed data.
An ADCP used to profile water currents is not automatically the ship's navigational speed log; a pitometer pressure pickup is not a Doppler transducer. SVC separates the physical underwater task from maker-specific instrument diagnosis and settings so the vessel can name the right specialist and acceptance records.
- Maker, model and exact sensor or pickup location
- Fault indication, readings, photographs and previous service notes
- Hull and instrument drawings, isolation arrangement and available spare
02
Inspect the hull fitting before choosing a method
SVC reviews the vessel drawings and accessible inboard side, then defines the underwater inspection area. The diver worklist can include the exposed face, surrounding coating and steel, mounting seat, fasteners and marine growth. The crew confirms the internal housing, gland, valve or line and the isolation state. Photographs and measurements help distinguish a sensor defect from a hull-fitting defect.
For an acoustic head, position relative to projections, other acoustic equipment and disturbed flow matters. Room to handle the assembly also matters. We agree the removal boundary only after checking the actual mounting and maker instructions; an instrument replacement does not automatically authorize cutting or hull renewal. If inspection finds damage to the sensor seat or adjacent plate, SVC scopes steel repair and welding separately against permits, vessel approval and any applicable survey review.
03
Pitometer pickup and pressure path
For a pressure-type pitometer log, SVC identifies the external pickup, its through-hull retention and the inboard pressure path. Cleaning a blocked pickup, repairing its mounting and renewing a part are distinct tasks. We check the part reference, orientation, access and isolation arrangement before the vessel releases an assembly for work.
Removal or opening of the through-hull assembly afloat is possible only where the vessel's approved arrangement permits safe isolation and closure. Otherwise the method requires controlled dock access. Opening a pressure line, sealing and later checks must be named in the agreed worklist.
04
ADCP head and acoustic path
An ADCP transducer needs its own maker drawing and mounting method. SVC examines the external head or window, seat, cable route and access for cleaning or removal. We record visible fouling, impact or coating damage and check how the proposed replacement would preserve specified orientation and beam clearance. Bubbles, flow disturbance and other acoustic equipment can affect performance, so a clean external face alone is not proof that the measured current profile is correct.
The appointed instrument specialist handles maker-specific alignment, software settings and data checks with the vessel. SVC records the physical work and as-fitted arrangement. Any sea acceptance or survey result is a separate agreed step, not a result promised here.
05
Speed-log transducer and display boundary
A ship speed log may use a Doppler transducer, a pressure pickup or another measurement arrangement. SVC checks the installed model before planning hull-side repair. External fouling, a damaged face, loose housing, cable fault and wrong displayed value must not be quoted as the same defect. Speed through water and speed over ground are also different outputs; the vessel must identify which reading is affected.
We define whether the assignment concerns the underwater element, through-hull fitting, inboard cable or a combined renewal. The vessel and instrument technician agree power, signal, bridge-interface and maker calibration checks after physical work. A dockside visual inspection cannot replace an underway check where one is specified.
06
Safe diver access and the watertight boundary
SVC plans the diver task against the berth or anchorage, depth, visibility, current, vessel movement and terminal permission. Before a diver enters the water, the vessel and dive team agree permits and isolation of propulsion, thrusters, intakes, discharges and other hazards. The master and crew control the internal watertight boundary. Hot work, cutting or a new hull opening requires a separate approved method and any appointed survey attendance.
Not every housing can be renewed afloat. SVC documents the fitting and proposes either an afloat or drydock sequence against the actual isolation and access. Hai Phong, Cai Mep and Thi Vai, and Vung Tau are representative enquiry areas; permission and safe diving conditions are checked for the exact berth or anchorage. See underwater inspection and hull cleaning in Vietnam for broader diver inspection; the sensor worklist remains vessel-specific.
07
Checks, records and quotation inputs
The agreed scope names the checks after fitting: seating and fasteners, accessible seal or gland, inboard leakage inspection, cable or pressure-line connection, power and displayed data where applicable. Maker instructions and the vessel's survey requirements determine calibration, an underway trial or formal acceptance. SVC records actual findings, fitted part references, photographs, measurements and outstanding items; no successful test or certificate is claimed in advance.
Email the repair desk with the work window and drawings. A photograph of the external head helps, but cannot replace the through-hull and isolation drawing. SVC reviews spare availability, diving method and instrument attendance before defining the work and price.
- Vessel position, berth or anchorage, ETA, sailing time and access restrictions
- Maker/model, part number, fault description, alarms and current readings
- Hull location, mounting and isolation drawings, inboard and underwater photographs
- Available spares, prior reports and required diver, instrument or surveyor attendance
- Required checks, report format and decision deadline
08
Pitometer, ADCP and speed-log questions
Can a pitometer pickup be renewed while the vessel is afloat?
Only if the actual through-hull arrangement permits safe isolation and closure and the vessel approves the method. SVC examines the drawings and access first; otherwise we plan controlled dock access.
Is an ADCP the same instrument as a ship speed log?
An ADCP current profiler is not automatically the vessel's approved navigational speed log. Confirm the installed model, outputs and acceptance requirements; some acoustic systems can produce vessel-velocity data as well as current profiles.
Does external cleaning prove the reading is accurate?
No. Cleaning and visual inspection address external condition. Power, signal, orientation, settings and any maker-required calibration or underway check are separate agreed tasks.
What records will SVC provide?
SVC records the appointed physical work, findings, photographs, fitted parts, accessible sealing checks and outstanding items. The exact report, instrument readings and survey attendance are defined in the job worklist.
What should we send for a quotation?
Send the maker/model, part reference, symptom, hull and isolation drawings, photographs, vessel position and window, available spares, required diver access and checks or survey deadline. SVC then defines a bounded method for that vessel.
Send the instrument fault and vessel window
Email the maker and model, affected pickup or transducer, fault readings, hull fitting and isolation drawings, photographs, exact berth or anchorage, ETA, sailing time and required diving, instrument or survey records.