PSS Shaft Seal 1-1/2 Inch Shaft with 2-5/8 Inch Stern Tube - Marine Mechanical Seal

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

Shaft Diameter: 1-1/2"
Stern Tube Diameter (D): 2-1/2" to 2-5/8"
Total Length (A): 9.175"
Total Length (compressed) (Compressed A): 8.175"
Rotor Diameter (B): 3.75"
Carbon Cuff Diameter (C): 3.25"
Stern Cuff Length (E): 2"

The PSS Shaft Seal is the number one selling marine mechanical seal worldwide and is installed as standard equipment by many of the worlds most reputable boat builders / yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. Certified by Bureau Veritas, ABS & Rina: Boat builders / yards recognize the advantages and value of installing the PSS as it eliminates the maintenance, constant adjustment & cost associated with traditional packing type glands. Aside from these benefits, the PSS Shaft Seal helps to eliminate water in the bilge (100% water tight) & wear to the propeller shaft. The PSS Shaft Seal can be easily retrofitted and is available for shafts ranging from 3/4" (20mm) to 6" (150mm).

The PSS Shaft Seal is a mechanical face seal that is created between the flat surfaces of the rotating stainless steel rotor and the stationary carbon flange. The stationary carbon flange is attached to the vessels stern tube with hose clamps and the carbon flange is attached to the front side of the bellows with hose clamps. The stainless steel rotor is fit on the shaft in front of the carbon flange. The stainless steel rotor is used to compress the bellows before the collar is secured to the shaft with set-screws. This compression (pre-load) maintains contact between the faces and allows the PSS to compensate for the thrust from the propeller. The carbon flange is bored larger than the shaft diameter allowing it to "float" around the shaft and thus compensate for most misalignment and vibration problems. The stainless steel collar is sealed to the shaft by two o-rings that are recessed into the bore of the collar. These o-rings rotate with the shaft and stainless steel rotor and do not experience wear during operation.


**As with any rubber hose below waterline, the PSS bellows must be inspected on a regular basis for any sign of wear, aging or chemical deterioration. PYI suggests as preventative maintenance that the PSS bellow be replaced in six year intervals. During bellows replacement it is recommended the o-rings & set screws in the stainless steel rotor also be replaced."

Bellows may need to be more frequently inspected in an environment where non-sealed batteries emit sulfuric acid. Sulfuric acid vapor will accelerate rubber deterioration, as will an ozonater.

The Maintenance Kit includes the items you need to properly maintain your PSS Shaft Seal. Included in the kit is one (1) PSS bellow, two (2) O-rings, five (5) set screws, four (4) new hose clamps and an allen key.

The PSS Shaft Seal 1-1/2 inch shaft with a 2-5/8 inch stern tube diameter is a top-rated marine mechanical seal designed for reliable, maintenance-free operation. Recognized worldwide as the best-selling marine shaft seal, the PSS is installed as standard equipment by many leading boat builders and yards, and it offers an excellent retrofit solution for existing systems. Certified by Bureau Veritas, ABS, and RINA, this seal enhances vessel performance by providing a 100% watertight barrier that prevents water ingress into the bilge while reducing wear on the propeller shaft.

Constructed as a mechanical face seal, the PSS features a stainless steel rotor that creates a tight seal against a stationary carbon flange. The carbon flange is attached to the vessel’s stern tube, and the rotor is mounted on the shaft with set screws, ensuring secure and precise contact. The design allows for easy installation and alignment, with a floating carbon flange that accommodates shaft misalignment and vibration, thereby extending the seal’s lifespan and maintaining optimal performance. Pre-loading the rotor ensures consistent contact between the sealing faces, providing a durable seal that compensates for propeller thrust.

The PSS Shaft Seal is suitable for shafts ranging from 3/4 inch (20mm) up to 6 inches (150mm), making it versatile across various vessel sizes. Its robust design and high-quality materials make it a preferred choice for boat owners seeking a reliable, low-maintenance solution. Regular inspection of the bellows is recommended, especially in environments with sulfuric acid vapor or ozone exposure, which can accelerate deterioration. The included maintenance kit provides all necessary components—bellows, O-rings, set screws, hose clamps, and an Allen key—for routine upkeep, with a suggested replacement interval of six years to ensure optimal performance.

Whether upgrading an existing system or installing a new seal, the PSS Shaft Seal offers a proven, corrosion-resistant, and efficient sealing solution that minimizes water intrusion and shaft wear. Its ease of retrofit, certification standards, and durable construction make it the ideal choice for demanding marine applications, providing peace of mind and long-lasting protection for your vessel’s propulsion system.

Features:

• Shaft Diameter: 1-1/2 inch for versatile marine installation

• Stern Tube Compatibility:

  Truck Freight: No
  Oversized: No