Guide to Cutlass Bearings for Small Boats

Cutlass bearings, such as those produced by Exalto Bearings UK, are essential for supporting propeller shafts in small boats, ensuring smooth operation and protecting key components from wear. Available in various materials and configurations, these bearings cater to specific marine environments and operational needs.

Types of Cutlass Bearings

1. Brass-Shelled Bearings: Constructed with a durable brass shell, these bearings are highly resistant to corrosion, making them ideal for saltwater environments. Brass provides excellent structural integrity, allowing these bearings to endure the constant exposure to seawater without compromising performance.
   
2. Phenolic-Shelled Bearings: Lightweight and non-metallic, phenolic bearings are resistant to electrolysis, making them suitable for use with non-metallic stern tubes. The phenolic shell provides a rigid yet lightweight structure, reducing the risk of galvanic corrosion.
   
3. GRP Bearings: Made from fiberglass-reinforced plastic, these bearings are designed for lightweight or high-performance vessels. GRP offers a balance between strength and weight, making it ideal for applications where reduced weight is critical.
   
4. All-Rubber Bearings: Designed primarily for freshwater use, these bearings provide excellent flexibility and shock absorption. The rubber construction reduces noise and vibration, making them suitable for quieter operations in low-stress environments.
   
5. Polyurethane Bearings: These bearings excel in abrasive environments such as silty or sandy waters. Polyurethane linings are highly resistant to wear and tear, offering a longer service life compared to other materials in challenging conditions.
   

Construction of a Cutlass Bearing

Cutlass bearings consist of two primary components:

1. Shell: Made from materials like brass, phenolic resin, or GRP, the shell provides the structural strength necessary to hold the bearing in place within the housing. It ensures alignment under various loads.
2. Lining: The lining, typically rubber, nitrile, or polyurethane, features grooves to facilitate water lubrication and debris flushing. This design minimizes friction and heat buildup, ensuring smooth operation and extending the bearing’s lifespan.

Maintenance of Cutlass Bearings

Maintaining your cutlass bearings is crucial for ensuring long-term reliability and efficiency. Regular checks and proactive care can prevent costly repairs.

1. Inspection: Periodically inspect the bearing for signs of wear, misalignment, or debris buildup. Excessive noise or vibration may indicate an issue that requires immediate attention.
2. Cleaning: Flush the grooves with clean water to remove any sediment or marine growth that could impede performance. For vessels operating in silty waters, this should be done more frequently.
3. Replacement: Replace the bearing when the lining wears down to half its original thickness or if the shaft shows signs of excessive movement within the bearing.

Frequently Asked Questions

1. What’s the difference between rubber and polyurethane linings? Rubber is ideal for freshwater environments, offering flexibility and noise reduction. Polyurethane, on the other hand, is more durable in abrasive conditions like silty or sandy waters.
2. How do I measure for a replacement bearing? Measure the inner diameter (ID), outer diameter (OD), and length of the current bearing. Always refer to the manufacturer’s specifications for accuracy.
3. Can Exalto bearings be customized? Yes, Exalto offers tailored solutions for non-standard applications, ensuring a perfect fit for unique marine setups.
4. How long do cutlass bearings typically last? With proper maintenance, cutlass bearings can last several years. However, lifespan depends on usage, load, and environmental conditions.