Chicago & Great Lakes Marine Surveying Specialists

Stray electrical current and corrosion are among the most expensive and least understood causes of boat damage on the Great Lakes. Improper shore power, faulty marina wiring, bonding failures, or nearby vessels can quietly destroy underwater metals, thru-hulls, drives, shafts, and electrical systems — often without obvious warning.

Great River & Lakes Marine Surveying provides professional Stray Current, Electrolysis, and Corrosion Surveys throughout Chicago and the Great Lakes region, helping owners, buyers, marinas, and insurers identify electrical risks before they result in major failures or insurance disputes.

What Is Stray Current & Electrolysis?

Stray current corrosion occurs when unintended electrical current flows through seawater or freshwater, accelerating metal loss at an extreme rate. Unlike normal galvanic corrosion, stray current damage can destroy components in weeks or months instead of years.

Common Great Lakes causes include:

• Improper marina shore power wiring

• Reverse polarity or grounding faults

• Failed bonding systems

• Missing or incorrect anodes (especially in freshwater)

• Nearby vessels leaking current into the water

• DIY electrical modifications

 
Freshwater marinas — including many in Chicago, Lake Michigan, and inland lakes — are especially vulnerable because corrosion damage often goes unnoticed until failure occurs.
What Our Corrosion & Stray Current Survey Includes
Our inspection focuses on risk identification, documentation, and practical mitigation, not guesswork.

Survey Scope

• Visual inspection of underwater metals (where accessible)

• Bonding system review

• Shore power inlet and grounding inspection

• Electrical panel and AC/DC system overview

• Anode type, placement, and condition review (freshwater-appropriate materials)

• Identification of corrosion patterns consistent with stray current or galvanic activity

• Documentation of observed deficiencies with photographs

• Clear written findings suitable for owners, insurers, or marina management

 
Note: This survey is non-invasive and designed for diagnosis and risk assessment. It does not replace corrective electrical work by a licensed marine electrician.

When Is a Stray Current or Corrosion Survey Recommended?

This service is strongly recommended if:
 

• You are buying a used boat on the Great Lakes

• The vessel is kept plugged into shore power

• You see unusual or rapid anode loss

• You notice corrosion on drives, shafts, thru-hulls, or trim tabs

• A marina has reported electrical issues

• You are preparing for an insurance or lender survey

• The vessel has been stored in multiple marinas

• You are experiencing unexplained electrical or bonding problems

Chicago & Great Lakes–Specific Risks

Stray current issues are common in freshwater marinas, especially in:
 

• High-density slip environments

• Older marina electrical infrastructure

• Facilities with mixed vessel types and DIY electrical work

• Seasonal marinas with winter power shutdowns and spring reconnections
   

Many Great Lakes insurance claims involving corrosion are denied or disputed due to lack of proper documentation. A dedicated corrosion survey helps establish condition, identify exposure risks, and support future decisions.

Who This Survey Is For
 

• Boat buyers and sellers

• Owners concerned about unexplained corrosion

• Insurance underwriters and adjusters

• Marinas and dock operators

• Charter and commercial operators

• Owners preparing for haul-out or refit
   

Why Choose Great River & Lakes Marine Surveying?
 

• Great Lakes–focused marine surveying expertise

• Independent, unbiased inspections

• Clear, factual reporting — no sales pressure

• Experience with insurance and lender requirements

• Practical, real-world recommendations

• Chicago-based with regional Great Lakes coverage

We understand how freshwater corrosion behaves differently than coastal saltwater environments — and we tailor our inspections accordingly.

Pricing & Scheduling

Stray current and corrosion surveys are typically quoted based on vessel size, access, and scope.

📍 Service Area: Chicago, Lake Michigan, and Great Lakes region

📅 Scheduling: Flexible weekday availability during the boating season

FAQ Section:

Is stray current corrosion covered by insurance?

Coverage varies. Many policies exclude corrosion unless documented and mitigated. Early identification can help reduce disputes.

Can stray current damage occur in freshwater?

Yes — while galvanic corrosion is slower in freshwater, stray current damage can be severe and rapid.

Does this survey require a haul-out?

Not necessarily. Many indicators can be identified in-water, though haul-out can provide additional confirmation if needed.