Introduction to Hull and Machinery Insurance

Hull and Machinery (H&M) insurance is the cornerstone of marine property protection. It provides coverage for physical loss or damage to the vessel's structure (the hull) and the equipment that propels and operates it (the machinery). Unlike cargo insurance, which protects the goods being transported, H&M insurance protects the shipowner's capital asset.

For professionals preparing for the practice Marine questions, understanding the standard clauses is vital. Most international hull policies are based on the Institute Time Clauses (Hulls), developed by the International Underwriting Association. These clauses define the scope of coverage, the duties of the assured, and the mechanisms for claims settlement. To get a broader view of the industry, you can also refer to our complete Marine exam guide.

The Core Perils Covered

The Institute Time Clauses operate on a "Named Perils" basis. This means that for a claim to be valid, the cause of the loss must be specifically listed in the policy. The primary perils include:

  • Perils of the Seas: This includes extraordinary action of wind and waves, stranding, and collisions with other vessels or submerged objects. It does not include the ordinary wear and tear of the ocean.
  • Fire and Explosion: Direct damage caused by combustion or sudden pressure release.
  • Violent Theft by Persons from Outside: This excludes internal theft by crew members.
  • Jettison: The intentional throwing overboard of equipment or parts of the vessel to save the ship in an emergency.
  • Piracy: Acts of violence or detention by non-state actors for private ends.

Standard Perils vs. Additional Perils (Inchmaree)

FeatureStandard Marine PerilsInchmaree Clause Perils
Nature of CauseExternal (Sea, Fire, Piracy)Internal or Human Error
Latent DefectsNot CoveredCovered (excluding repair of defect)
Crew NegligenceGenerally excludedCovered (if not due to lack of due diligence)
Machinery BreakdownOnly if caused by external perilCovered if caused by crew error or defect

The Inchmaree Clause and Latent Defects

One of the most critical components of H&M insurance is the Inchmaree Clause (formally known as the Additional Perils Clause). Named after a famous legal case involving the steamer Inchmaree, this clause extends coverage to losses that occur due to internal failures rather than external sea perils.

The clause covers loss of or damage to the vessel caused by:

  • Accidents in loading, discharging, or shifting cargo or fuel.
  • Explosions on board or elsewhere.
  • Bursting of boilers or breakage of shafts.
  • Latent defects in the machinery or hull.
  • Negligence of Master, Officers, Crew, or Pilots.

Note for Exam Candidates: The Inchmaree Clause is subject to the Due Diligence Proviso. This means the loss must not have resulted from a lack of due diligence by the Assured, Owners, or Managers of the vessel. If the shipowner knew of a defect and failed to rectify it, the claim may be denied.

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The Running Down Clause (3/4ths Collision Liability)

Standard H&M clauses typically include a provision for collision liability. However, by tradition, the H&M policy only covers three-fourths of the liability incurred by the shipowner when their vessel collides with another. The remaining one-fourth is usually covered by a Protection and Indemnity (P&I) Club. This encourages shipowners to manage risks carefully through mutual associations.

H&M Policy Limitations and Conditions

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Applies to all claims except Total Loss
Deductible
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Duty of assured to minimize loss
Sue and Labor
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Depreciation allowance if not fixed
Unrepaired Damage
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Excluded during repair time
Wages and Maintenance

Pollution Hazard and General Average

H&M clauses also address the wider impact of marine casualties. The Pollution Hazard Clause covers loss or damage to the vessel caused by government authorities acting to prevent or mitigate a pollution hazard (e.g., if a government decides to scuttle a leaking wreck to prevent an oil spill).

Furthermore, H&M insurance covers the vessel's proportion of General Average and Salvage charges. General Average is a principle where all parties in a sea venture (ship, cargo, and freight) proportionally share losses resulting from a voluntary sacrifice to save the whole venture from a common peril. For more detail on this specific topic, see our article on General Average and York-Antwerp Rules.

Frequently Asked Questions

A Time Policy covers the vessel for a specific duration (usually twelve months), regardless of the number of voyages. A Voyage Policy covers the vessel for a specific journey from one port to another. Most H&M insurance uses the Institute Time Clauses (Hulls).
Under the Inchmaree Clause, the policy covers the damage caused by a latent defect, but it specifically excludes the cost of repairing or replacing the defective part itself. For example, if a defective bolt breaks and destroys an engine, the engine is covered, but the bolt is not.
A Constructive Total Loss (CTL) occurs when the cost of recovering and repairing the vessel exceeds its insured value. In this case, the shipowner can abandon the vessel to the underwriters and claim the full insured amount. Learn more about this in our guide on Actual vs. Constructive Total Loss.
No. Standard Institute Time Clauses (Hulls) exclude war, strikes, and civil commotions. These risks must be covered by a separate War Risks policy or by attaching specific War and Strikes clauses for an additional premium.