Why the diagnosis matters more than the repair

After a lightning event or a bad storm, the hardest question isn’t how to fix your boat. It’s knowing what is actually broken.

Fiberglass damage announces itself. Electrical damage hides. A vessel can start, run, hold charge and show a clean helm display while carrying a dozen components that are electrically compromised and weeks from failing. That gap between what the boat appears to be and what the boat is, is where owners lose money — either because the damage is missed at the time of the claim, or because it is discovered after the claim has been closed.

Your boat doesn’t have to take a direct lightning strike to suffer damage. Practical Sailor documents five distinct mechanisms by which lightning harms a vessel, and only one of them is the movie version. There is the direct strike. There is side flash, where current jumps from the primary path to another conductive object on board. There is a side strike that punches through the hull to reach the water. There are EMP-type induced surge currents, which appear in circuits that were never part of any strike path at all — the energy is induced into the wiring by the electromagnetic field, not conducted into it. And there is ground strike radiance from a nearby strike, with a risk radius quoted as far as 100 to 300 feet. A boat two slips over from the one that got hit can end up with the more expensive problem.

This page describes what our diagnostic process actually consists of, and why we run it the way we do.

Sequential single-system testing — and why it is not optional

Here is the part most owners have never had explained to them.

When a vessel has taken induced current, you cannot assume that any given board, module or circuit is healthy. Some are fine. Some are destroyed. And some are in the middle state that causes the real damage: partially compromised, still conducting, but with a fault path that did not exist before the event.

If a technician powers the boat up as a whole to “see what works,” a compromised component can put current where it does not belong and take a healthy component with it. A shorted board on a shared bus can damage the device next to it. A failed regulator can push voltage into a network that was intact five seconds earlier. We have seen post-event vessels where the second wave of damage was created during troubleshooting, not during the storm.

So we don’t do that. We isolate. Each system is separated from the others, energized on its own under controlled conditions, and evaluated on its own merits before it is ever allowed back onto the vessel’s common electrical architecture. It is slower. It is the only defensible way to do it on a boat that has taken an electrical event, and it is the difference between a diagnostic that protects your remaining good equipment and one that quietly eats it.

The same discipline is what produces a scope of repair an adjuster can actually work with. “The electronics are bad” is not a scope. A system-by-system record of what was tested, what was measured, and what failed, is.

What we test

Impedance and resistance circuit testing

Before anything is powered, we characterize the circuits themselves. Resistance and impedance measurements across runs, terminations, grounds and bonding conductors tell us where conductor damage, degraded insulation, high-resistance connections and partial faults are hiding. Lightning energy frequently damages wire without visibly marking it — the jacket looks perfect and the conductor underneath is no longer the conductor it was. Measurement finds that. Inspection alone does not.

Engine ECU and ECM diagnostic scanning

Inboard and outboard, gas and diesel, we scan engine control units and engine control modules for stored and active fault codes, sensor plausibility errors, and communication faults on the engine network — including Yamaha and Mercury platforms. Engines are one of the most consequential findings in any lightning claim, because an ECU or ECM is both expensive and easy to overlook when the engine still cranks and runs. A scan that documents fault history at the time of inspection is far more useful six weeks later than a memory of how it sounded at the dock.

Sensor testing throughout the engine and vessel

Sensors are small, numerous, cheap individually and expensive in aggregate. We test sensors across the engine and across the vessel — temperature, pressure, position, level, flow, trim and monitoring senders — because a sensor that reads plausibly but incorrectly will drive a control system to do the wrong thing and will not necessarily set a code. This is one of the classic late failures on a lightning boat.

Navigation, communication and electronics testing

GPS, radar, sonar and depth, VHF, autopilot, multifunction displays and the NMEA 2000 backbone all get tested individually, including the network itself — power, termination, drop cables, backbone continuity and node behavior. Networked helms are especially vulnerable to induced current, because the network is a long conductive path threaded through the entire boat, and because a single failing node can drag the whole bus down in a way that looks like ten failures instead of one. Sorting genuine multi-device failure from one bad actor is worth real money on a claim.

Batteries, chargers, inverters and isolation transformers

We evaluate battery banks, charging systems, inverters and isolation transformers as a group, because they interact. A charger that survived the event but now delivers a bad profile will shorten the life of a bank that survived the event too, and the owner will pay for both later. Isolation transformers in particular are worth close attention on shore-powered vessels after a storm.

Shore power and AC system evaluation

Shore power inlets, cordage, ELCI and breaker protection, panel wiring, polarity and grounding, and AC branch circuits are inspected and tested with reference to ABYC E-11, which covers AC and DC electrical systems on boats. AC faults after a storm are a safety issue before they are a repair issue, and they are frequently the finding that keeps a boat from being returned to service the same week.

Bilge pumps and other pump circuits

Bilge pumps, float switches, washdown, macerator, livewell and transfer pumps get tested with their circuits and their controls. Bilge pumping is the system with the shortest path between “not working” and “boat on the bottom,” which is why it is tested early and tested again before the vessel leaves.

Bonding and grounding inspection per ABYC E-2

We inspect the bonding and grounding system against ABYC E-2, tracing bonding conductors, connections, and continuity to underwater metals, and documenting where the system is intact, degraded or absent.

This matters more than almost anything else on the list, and there is good evidence for why. Vessels with a bonding system — even a substandard one — are less likely to suffer damage than vessels without. The most sobering documented case is a trimaran with no bonding system and non-metallic seacocks, in which lightning exited through a transducer and the hull; the boat sank. Bonding does not make a boat lightning-proof. ABYC TE-4, the marine lightning protection standard, is explicit that complete protection from equipment damage or personal injury is not implied by compliance. But the presence and condition of a bonding system is one of the most meaningful things we can tell you about your vessel’s exposure, and one of the most useful things to have documented before the next season.

Transducers and through-hulls

Transducers, through-hulls, seacocks and any other underwater penetration on the current’s possible exit path are inspected and tested. Exit-point damage is the failure mode that turns an electrical claim into a sinking, and it is not always visible from inside the bilge with a flashlight. We look at it deliberately, every time.

What you get at the end

A written record of what was tested and what was found, system by system, with measurements — not adjectives. That record becomes the basis for the scope of repair and the estimate, and it is what we provide when we coordinate with your adjuster. We handle the claim documentation and the repair side end to end: documentation, scope of repair, estimate, supplements as additional damage surfaces, adjuster coordination, and the repair itself.

One thing to expect, because it surprises people: damage surfaces late. Components containing semiconductors very commonly fail the first time they are powered up, days after the event. That is normal, it is well known in the industry, and it is a large part of why insurers often leave lightning claims open rather than closing them at first inspection. If something fails after your boat is back in the water, tell us. That is what the supplement process is for.

Statewide, and we come to the boat

Our facility is in Stuart, on the Treasure Coast, and we serve all of Florida. If your vessel cannot safely be run to us, we transport it. See Statewide Florida Boat Transport for how that works.

Frequently Asked Questions

Q: My boat runs fine after the storm. Do I still need an electrical diagnostic?
A: Usually yes, and this is the single most common expensive mistake we see. Lightning damage frequently appears days or weeks later, because components containing semiconductors often fail the first time they are powered up after the event. A boat that starts and runs at the dock can still be carrying compromised boards, sensors and network devices. An inspection while the claim is open costs you nothing and protects the claim; discovering the damage after the fact is a much harder conversation.

Q: Lightning hit a boat near mine, not mine. Can that damage my electronics?
A: Yes. Practical Sailor documents ground strike radiance from nearby strikes, with a risk radius quoted as far as 100 to 300 feet, along with EMP-type induced surge currents that appear in circuits that were never part of a strike path at all. Your boat doesn’t have to take a direct hit to suffer damage. If a strike happened in your marina, get the vessel looked at.

Q: Why do you test one system at a time instead of just powering the boat up?
A: Because a damaged component can take a healthy one with it. After an electrical event, some components are fine, some are destroyed, and some are partially compromised but still conducting. Energizing everything at once lets a faulty board or module push current where it shouldn’t go and create a second round of damage during troubleshooting. Isolating and testing each system on its own is slower and it protects the equipment that survived.

Q: Can you scan my engine’s computer?
A: Yes. We perform ECU and ECM diagnostic scanning on inboard and outboard engines, including Yamaha and Mercury platforms, and we document stored and active faults, sensor plausibility errors and network communication faults at the time of inspection. Engines are a high-value finding in lightning claims and are easy to overlook when the engine still runs.

Q: What is a bonding system and why do you keep bringing it up?
A: A bonding system electrically ties underwater metals and other components together to a common potential; ABYC E-2 is the standard that covers it. It matters because vessels with a bonding system — even a substandard one — are less likely to suffer lightning damage than vessels without one. In one documented case, a trimaran with no bonding and non-metallic seacocks sank after lightning exited through a transducer and the hull. Bonding is not a guarantee. ABYC TE-4, the marine lightning protection standard, states plainly that complete protection from equipment damage or personal injury is not implied.

Q: Do you handle the insurance side, or do I?
A: We handle the contractor side of it completely. We document the damage, write the scope of repair, prepare the estimate, submit supplements when additional damage surfaces, coordinate with your adjuster, and perform the repair. We are your repair contractor, not your adjuster — the coverage decision is between you and your carrier, and we give both of you an accurate, evidence-based picture of the damage to work from.

Q: How fast can you get to my boat?
A: Our storm response hotline is answered by a live person 24 hours a day, and we guarantee an inspection within 48 hours. The initial storm damage inspection is free. We serve all of Florida, and if your vessel is not safe to run, we transport it.