PSS Shaft Seal 02-212-400 2-1/2" Shaft 4" Stern Tube Marine Mechanical Seal

PSS Shaft Seal

<h3>About PSS Shaft Seal</h3><p><strong>PSS Shaft Seal</strong>, manufactured by PYI Inc., has been redefining marine drivetrain integrity since its introduction in 1991. As the world's best-selling marine mechanical seal, the PSS system is trusted by boat builders, commercial operators, and recreational boaters across every segment of the industry — from weekend sailors to superyacht owners and military vessel operators.</p><p>At the heart of the PSS system is a deceptively simple but highly engineered concept: replace the old-fashioned, constantly dripping stuffing box with a true dripless, maintenance-free mechanical face seal. Traditional packing glands require ongoing adjustments and periodic repacking to manage water intrusion; the PSS eliminates that burden entirely. The result is a bilge that stays dry, a propeller shaft that experiences far less wear, and a drivetrain that demands almost no attention once installed.</p><p>The sealing action is created between two precision-lapped surfaces — a rotating stainless steel rotor and a stationary carbon-graphite flange. The carbon composite used in PSS seals is rated to withstand temperatures up to 500°F (260°C) and will not melt if the seal runs briefly dry, a critical safety advantage over lip seals or plastic face seals. The carbon stator is over-bored to float around the shaft, naturally compensating for misalignment and vibration, while a pre-loaded bellows assembly accommodates the fore-and-aft thrust movement inherent in propeller-driven vessels.</p><p>PSS offers several product lines to match specific applications. The <strong>Type A</strong> seal covers shafts from 3/4&quot; to 3-3/4&quot; in diameter, while the <strong>Type B</strong> handles larger commercial shafts from 4&quot; to 6&quot;. The <strong>PSS PRO</strong> adds a reinforced silicone bellows, a secondary shaft retention collar, and premium 316 stainless steel hardware for demanding environments such as high-pressure, corrosive, or heavy-duty commercial applications. The entire range is certified by ABS, Bureau Veritas, and RINA — recognized certifying authorities in the global marine industry.</p><p>Beyond the seal itself, PSS supports the full service life of its products with a suite of <a href="/200756-packing-boxes-shaft-seals-accessories-pss-shaft-seal-11555">packing boxes, shaft seals, and accessories</a> including bellow maintenance kits, replacement O-rings, hose clamp kits, and cooling water hose assemblies. This ecosystem ensures that boatowners and yards can keep a PSS installation performing at its peak without sourcing components from multiple suppliers.</p><p>The brand's <a href="/11555-pss-shaft-seal-gaskets-seals-201268">gaskets and seals</a> product line rounds out the offering, providing the precision sealing components — including O-rings, carbon stators, and rotor assemblies — that are integral to both new installations and long-term maintenance. For vessels requiring complementary <a href="/11555-pss-shaft-seal-bearings-21574">bearings</a> as part of a complete shaft system solution, PSS also offers compatible drivetrain components to support a fully integrated installation.</p><p>Whether specified as factory-standard equipment by a premium boatyard or selected as a retrofit upgrade on an existing vessel, the PSS Shaft Seal represents one of the most impactful and cost-effective improvements a boatowner can make to their drivetrain. Decades of commercial service records — including vessels logging more than 40,000 engine hours on original components — speak to the engineering rigor behind every seal that leaves the factory.</p>