What causes corrosion in metal-hulled boats?

Corrosion in aluminum and steel boats is primarily caused by standing bilge water that remains in contact with metal surfaces. This moisture triggers electrolysis, galvanic corrosion, and calcification. Sealed compartments can trap water out of sight, allowing damage to progress undetected for months or years.

How does a dry bilge system prevent yacht corrosion?

A dry bilge system like Arid Bilge uses continuous vacuum extraction to remove moisture from every bilge zone before it can accumulate. Unlike traditional bilge pumps that only activate when water reaches a certain level, a dry bilge system keeps compartments completely moisture-free year-round, eliminating the conditions that cause corrosion.

What types of vessels benefit from a dry bilge system?

Any metal-hulled vessel benefits from a dry bilge system, including aluminum yachts, steel commercial fishing boats, military craft, and luxury motor yachts. Fiberglass boats also benefit from reduced odors, improved air quality, and protection of mechanical systems from moisture damage.

How much does corrosion damage cost to repair on a yacht?

Corrosion repair costs vary widely depending on severity. In one documented case, hidden moisture under a sealed hatch on a 120-foot aluminum yacht caused a fist-sized cavity that required $40,000–$50,000 in repairs. Early prevention with a dry bilge system is significantly more cost-effective than structural repairs.

What is the difference between a dry bilge system and a traditional bilge pump?

Traditional bilge pumps are reactive—they only activate when standing water reaches a float switch. A dry bilge system is proactive, continuously extracting moisture and humidity before water can accumulate. This prevents the conditions that lead to corrosion, odors, and mold rather than simply removing water after it collects.

Metal Hull Yacht Corrosion Prevention

By Alfred BaurleyPublished On: January 22, 2026Categories: Articles, Blog

Metal-hulled vessels are built for strength—but they’re also highly vulnerable to one silent threat: bilge water.

Moisture trapped in metal compartments leads to corrosion, electrolysis, and calcification, compromising the structural integrity of even the strongest boats. Without early intervention, this moisture becomes a costly, silent killer.

A Real-World Example: Buckpasser

One powerful case study is the Buckpasser, a 120-foot aluminum motor yacht built in 1985 by Hitachi Zosen. After discovering severe pitting and corrosion due to stagnant bilge water, the captain reached out for help.

We inspected the vessel at Bradford Marine and recommended an Arid Bilge Series 9 system with nine pickup zones, an Eco-Friendly Discharge Companion, and an Eco Alarm System. Once installed, the transformation was immediate: moisture was eliminated from the bilge zones, and the captain could monitor everything through a clear-view chamber. The crew immediately noticed drier air, fewer odor issues, and a stabilized environment.

Further inspection revealed a fist-sized cavity caused by hidden moisture under a sealed hatch—damage that cost $40,000–$50,000 in repairs. Had a dry bilge system been installed sooner, this could have been entirely avoided.

Additionally, widespread corrosion and rust bloom were present throughout the lazarette. The Arid Bilge System quickly removed the source of those problems—standing water—without any manual effort from the crew.

Aluminum yacht hull corrosion damage from bilge water

Hidden Dangers of Bilge Water in Metal Boats

Electrolysis & Galvanic Corrosion – Accelerated by metal-water contact
Calcification – Hard mineral buildup from stagnant water
Structural Weakening – Prolonged exposure leads to metal fatigue
Hidden Damage – Sealed compartments can trap water out of sight

Metal Hull Vessel - Preserving the hull and minimizing corrosion.

These conditions can exist undetected for months or years, quietly degrading your vessel’s most critical systems. By the time corrosion appears visibly, significant damage is already done.

How Arid Bilge Solves It

Arid Bilge Systems provide continuous vacuum removal from every bilge zone. It’s a proactive, automated system that:

Keeps compartments bone-dry year-round
Uses an Eco-Friendly Oil/Water Separator for clean, compliant discharge
Alerts crew instantly to unexpected moisture with a built-in alarm system

Unlike traditional pumps that only activate with standing water, Arid Bilge prevents moisture from accumulating at all.

Long-Term Value

Installing Arid Bilge means:

Extending hull life by stopping internal corrosion before it starts
Reducing maintenance costs from fewer part replacements and dry service bays
Improving air quality for crew and equipment longevity
Preserving vessel value by avoiding unsightly rust or rot

A dry bilge system also makes ongoing inspections easier and ensures better working conditions in confined compartments.

Protecting Your Investment

For any metal-hulled vessel—whether it’s a luxury yacht, commercial fishing boat, or military craft—dry bilges are essential.

Arid Bilge Systems protect your hull, your systems, and your reputation. Our technology is trusted by builders, captains, and professionals around the world to stop the invisible threat of corrosion before it begins.

Don’t let trapped moisture eat away at your investment.