PSS Shaft Seal 2-1/2" Shaft 4" Tube

The PSS Shaft Seal 2-1/2" Shaft 4" Tube is a premier solution for marine vessel shaft sealing, offering unparalleled reliability and efficiency. Trusted by top boat builders and marine enthusiasts worldwide, this advanced mechanical seal ensures a watertight and maintenance-free operation for your vessel.

Product Specifications

Measurement	Dimension
Shaft Diameter	2-1/2"
Stern Tube Diameter (D)	4"
Total Length (A)	9.625"
Total Length (Compressed A)	8.375"
Rotor Diameter (B)	4.2"
Carbon Cuff Diameter (C)	3.75"
Stern Cuff Length (E)	2"

Why Choose the PSS Shaft Seal?

The PSS Shaft Seal stands as the number one selling marine mechanical seal globally, installed as standard equipment by many of the world's most reputable boat builders and yards. It is also the premier choice for retrofit applications in the aftermarket sector.

• Certified Quality: Certified by Bureau Veritas, ABS, and RINA, ensuring top-tier performance and safety standards.
• Low Maintenance: Eliminates the need for traditional packing glands, reducing maintenance, constant adjustments, and associated costs.
• Enhanced Protection: Prevents water ingress into the bilge (100% watertight) and minimizes wear on the propeller shaft.
• Versatile Fit: Compatible with shaft diameters ranging from 3/4" (20mm) to 6" (150mm), allowing for easy retrofitting.

Advanced Mechanical Design

The PSS Shaft Seal employs a sophisticated mechanical face seal, formed by the interaction of the rotating stainless steel rotor and the stationary carbon flange. Key components and their functions include:

• Stainless Steel Rotor: Mounted on the shaft in front of the carbon flange, it compresses the bellows to maintain contact between seal faces and compensate for propeller thrust.
• Carbon Flange: Attached to the vessel's stern tube and the bellows, it is bored larger than the shaft diameter to allow floating movement, effectively compensating for misalignment and vibration.
• Sealed Collar: Secured to the shaft with set-screws, featuring two o-rings recessed into the collar bore that rotate with the shaft and rotor without experiencing wear.

Maintenance and Longevity

Regular Inspection: As with any rubber hose below the waterline, the PSS bellows should be inspected regularly for signs of wear, aging, or chemical deterioration.

Preventative Maintenance: PYI recommends replacing the PSS bellows every six years. During this replacement, it is advisable to also replace the o-rings and set screws in the stainless steel rotor.

Environmental Considerations: In environments where non-sealed batteries emit sulfuric acid, more frequent inspections are necessary as sulfuric acid vapor accelerates rubber deterioration. Additionally, ozone exposure can also degrade rubber components.

Maintenance Kit

Ensure the longevity and optimal performance of your PSS Shaft Seal with our comprehensive Maintenance Kit. The kit includes:

• One (1) PSS bellows
• Two (2) O-rings
• Five (5) set screws
• Four (4) new hose clamps
• One (1) Allen key

Additional Resources

Download the Brochure (PDF)

Orders of physical products placed by 3 PM EST M-F typically ships the same day, if all requested items are in stock. Weekend orders will typically ship on Monday.

Shipping takes 2-7 days.

We currently ship to the Contiguous 48 States.

Life of Sailing merch is custom made for the customer after an order is placed. Total turnaround is typically 7-14 days from order to doorstep.