Sure Shot Marine

Jeremyn Horsley  ·  Marine Electrician

San Francisco Bay Area

Diagnostic Capabilities

Diagnosis based on measurement, not guesswork. The instruments I bring aboard, and what each one isolates.

Serving Alameda · Oakland · Berkeley · Richmond · Sausalito · San Francisco Bay Area marinas

Diagnose First

Parts get replaced. Faults get found. Those are not the same thing. Before anything is swapped out, the fault is located and its cause identified. The instruments below measure current, leakage, insulation, power quality, corrosion potential, and network health directly, so the diagnosis rests on measurement rather than assumption. Every job ends with a written report of what was found and what it takes to correct it.

Diagnostic Equipment

The instruments used on site, grouped by what they measure.

Imaging & Waveform Capture

Thermal Imaging Camera

Infrared inspection of panels, terminations, and wiring under load. Identifies overheating connections before failure.

Handheld Oscilloscope

Captures alternator ripple, voltage transients, and switching noise as waveforms. Characterizes intermittent and time-dependent faults.

Power Quality Analyzer

Logs voltage imbalance, harmonic distortion, frequency, and sags across all phases. Used on generator, inverter, and three-phase distribution faults.

Logging Multimeter

Records voltage and current unattended over extended periods. Captures intermittent faults that cannot be reproduced on demand.

Current, Resistance & Insulation

DC Clamp Meter with Inrush Capture

Measures current on live circuits without disconnection. Quantifies parasitic drain, charging output, and motor inrush.

AC Leakage Clamp Meter

Resolves leakage current to fractions of a milliamp. Isolates ELCI trips and AC leakage into the water.

Insulation Resistance Tester

High-voltage testing of wiring, shore cords, and motor windings. Detects degraded insulation before breakdown.

Low-Resistance Ohmmeter

Measures crimps, lugs, and switch contacts in milliohms. Identifies high-resistance terminations on high-current circuits.

Corrosion & Stray Current

Silver/Silver-Chloride Reference Electrode

Measures hull potential in the water against a calibrated reference. Evaluates cathodic protection and anode performance to ABYC E-2.

DC Milliamp Clamp Meter

Measures galvanic and stray DC current on bonding conductors. Distinguishes normal protection current from leakage.

Gauss Meter

Measures magnetic fields on shafts, struts, and fittings. Detects DC current paths and magnetization caused by stray current.

Galvanic Isolator Tester

Verifies forward-voltage threshold and fail-safe continuity of the galvanic isolator. Confirms the A-28 protective device is functioning rather than failed open or shorted.

Networks, RF & Data Bus

NMEA 2000 Network Analyzer

Measures bus voltage, error rates, and traffic at the backbone. Isolates wiring and termination faults from device failure.

Ethernet Cable Qualifier

Tests network cabling, PoE delivery, and switch ports. Used on onboard camera, radar, and data networks.

Antenna & SWR Analyzer

Sweeps VHF and AIS antenna systems to measure feedline loss and match. Isolates antenna, cable, and radio faults.

CAN Bus Analyzer

Reads J1939 and CAN data from diesel and electric propulsion systems. Accesses system-reported sensor and fault data.

Components & Batteries

Battery Analyzer

Conductance testing of start and house banks. Determines state of health independent of resting voltage.

LCR Meter

Measures inductance, capacitance, and resistance on windings and components. Identifies shorted transformers and failing coils.

Carbon Pile Load Tester

Applies a calibrated load to start and house banks while measuring voltage under draw. Confirms cranking capacity that a no-load reading can mask.

Semiconductor Component Tester

Tests diodes, transistors, and capacitors at the device level. Isolates failed alternator rectifiers and faults on regulator, charger, and controller boards.

Have a Fault That Won't Quit?

Intermittent, hidden, and hard-to-find problems are the work I take on. Based in the East Bay, serving Alameda, Oakland, Berkeley, Richmond, Sausalito, and surrounding Bay Area marinas.