Tides Marine FSK-1500-3500-0 SureSeal Shaft Seal

Tides Marine FSK-1500-3500-0 SureSeal Drip-Free Self-Aligning Shaft Seal Kit for 1-1/2 in. Shaft and 3-1/2 in. Stern Tube – Single Water Injection (Without Crossover)

Shaft OD: 1-1/2 in.
Stern Tube OD: 3-1/2 in.
Minimum Installation Distance: 7-1/4 in. (184.2 mm)

The Tides Marine FSK-1500-3500-0 SureSeal is a drip-free, self-aligning propeller shaft seal engineered for 1-1/2 in. propeller shafts and 3-1/2 in. stern tubes. Equipped with a single water injection fitting (without crossover), this shaft seal delivers dependable, maintenance-friendly performance while eliminating the leaks associated with conventional stuffing boxes. The minimum required distance from the end of the stern tube to the coupler is 7-1/4 in. (184.2 mm), ensuring proper installation and optimal operation.

Housing

The SureSeal housing is manufactured from fiber-reinforced composite material, providing exceptional strength while remaining lightweight. Unlike conventional metallic housings, it is resistant to corrosion and electrolysis, does not absorb water, and maintains dimensional stability in harsh marine environments for years of dependable service

Bearing

An integral water-lubricated PTFE bearing supports the propeller shaft while minimizing friction and wear. Engineered for long service life, it provides smooth, quiet operation and helps reduce maintenance requirements in demanding marine applications.

Articulating Hose

Connecting the SureSeal to the vessel is now easier with an articulating hose that automatically positions the seal at the correct operating distance from the stern tube. No measurements are required, simplifying installation while ensuring proper alignment. The articulating hose also reduces side loads caused by minor shaft misalignment, helping extend the service life of both the lip seal and the bearing.

Lip Seal Replacement

The SureSeal features a removable front cap that provides quick access to the lip seal. When used with a Spare Seal Carrier, the lip seal can be replaced without removing the propeller shaft—even while the vessel is in the water—restoring the seal's 100% watertight performance.

Water Injection Fitting

This model incorporates a single 316 stainless steel water injection fitting that supplies cooling and lubricating water to the shaft seal during operation. The fitting includes a protective plastic cap that can temporarily restrict water flow into the vessel if the water supply hose is removed during maintenance.

Before Ordering

SureSeal kits include the shaft seal assembly, an articulating hose, four stainless steel clamps, and the appropriate hose adapter tube. Before purchasing, confirm the following:

• Propeller shaft outside diameter.
• Stern tube outside diameter.
• Minimum installation distance between the end of the stern tube and the shaft coupler (7-1/4 in. / 184.2 mm for this model).
• Water injection configuration required for your propulsion system.

Key Features of the SureSeal

• Drip-free shaft seal design for a cleaner, drier bilge.
• Self-aligning construction compensates for minor shaft misalignment.
• Single water injection fitting designed for single-engine installations.
• Fiber-reinforced composite housing resists corrosion and electrolysis.
• Integral water-lubricated PTFE bearing for smooth operation and extended service life.
• Articulating hose automatically positions the seal at the correct operating distance from the stern tube—no measurements required.
• Replaceable lip seal without removing the propeller shaft when used with a Spare Seal Carrier.
• 316 stainless steel water injection fitting for long-lasting marine durability.
• Minimal maintenance compared to traditional stuffing boxes.
• No winterization required, and winterizing fluids will not damage the SureSeal.
• ABS and Lloyd's Type Approved.
• OEM-quality solution trusted by leading boat manufacturers worldwide.