PSS Type A Shaft Seal

PSS Type A Seals

Fits 3/4" to 3-3/4" Shafts
(20mm to 95mm)

PSS Type B Shaft Seal

PSS Type B Seals

Fits 4" to 6-1/2" Shafts
(100mm to 150mm)

PSS Type C Shaft Seal

PSS Type C Seals

Fits 6-1/2" to 8" Shafts
(165mm to 203mm)

PSS PRO Shaft Seal


Fits 1-1/4" to 3-3/4" Shafts
(32mm to 95mm)

PSS Rudder Post Seal

PSS Rudder Post Seals

Fits 1-1/4" to 6" Shafts
(32mm to 150mm)

PSS Maintenance Kit

PSS Type A Maint. Kits

Fits 3/4" to 3-3/4" Shafts
(20mm to 95mm)

PSS PRO Maintenance Kit

PSS PRO Maint. Kits

Fits 1-1/4" to 3-3/4" Shafts
(32mm to 95mm)

PSS T-Kits

PSS Accessories

T-Kits & O-Ring Kits

PSS Flange and Bladder System

Flange & Bladder System

Fits 2-1/2" to 6" Shafts
(63.5mm to 150mm)

Shaft Retention Collar

Shaft Retention Collar

Designed to help retain the shaft in your vessel

PSS Shaft Seals

The PSS Shaft Seal is the #1 selling marine mechanical seal worldwide and is installed as standard equipment by many of the worlds most reputable boat builders and boat yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. Boat builders and boat yards recognize the advantages and value of installing the PSS as it eliminates the maintenance, constant adjustment and cost associated with traditional type of packing glands. Aside from these benefits, the PSS Shaft Seal helps to eliminate water in the bilge (100% water tight) and wear to the propeller shaft. Any vessel can easily be retrofitted with a PSS Shaft Seal, and is available for shafts ranging from 3/4” to 6-1/2” (20mm to 150mm).

How Does It Work

The PSS Shaft Seal is a mechanical face seal. The sealing surface 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 front side of the bellow with hose clamps, and the back end of the bellow fits over the stern tube and is secured 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 bellow before the rotor is secured to the shaft with set-screws. This compression (pre-load) maintains constant contact between the two flat faces of the stainless-steel rotor and carbon flange, allowing the PSS to compensate for the variable fore and aft movement due to propeller thrust. The carbon flange is over-bored to the shaft diameter allowing it to float around the shaft and thus compensate for most misalignment and vibration problems. The stainless-steel rotor 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.

How a PSS Seal works

PSS Shaft Seal Components

Click or hover over the components to see more information!

stainless steel rotor
carbon stator
rubber bellow


The PSS Shaft Seal has been thoroughly tested and approved by these certifications.

ABS Certification


What Is A PSS Shaft Seal Video

Contact PYI

Need technical support? Can't find what you're looking for?