| Consideration | PSS | Tides SureSeal |
|---|---|---|
| Sealing mechanism | Carbon and stainless mechanical faces; rotor O-rings rotate with the shaft. | Replaceable lip seal contacting the shaft, composite housing and an integral PTFE alignment bearing. |
| Shaft condition | Dynamic seal runs on the rotor face. Shaft still needs correct sizing, alignment and sound surfaces where O-rings sit. | Requires an unblemished shaft surface at the lip. Tides says a face seal may suit better where damage cannot be avoided by repositioning the hose. |
| Cooling | A vent may suit low-speed applications without a shaft-log bearing. High-speed and other specified applications require positive feed. | Pressurised cooling-water feed required; crossover arrangement available for twin engines. |
| Service | Regular inspections and scheduled bellows replacement. Installation requires haul-out. | A preinstalled spare-seal carrier allows replacement of the lip seal afloat without uncoupling the shaft. |
| Engine suitability | Specify for the complete vessel installation. | Tides does not recommend SureSeal for engines with fewer than four cylinders. |
Face seal or shaft-contacting lip
PSS creates its working seal between carbon and stainless faces. Tides SureSeal uses a replaceable lip running against the shaft, supported by a composite housing and integral PTFE alignment bearing.
This changes which surfaces deserve attention during a refit. With PSS, the rotor and carbon provide the dynamic sealing faces. With SureSeal, the shaft surface at the lip is part of the working seal.
Shaft condition can favour PSS
Tides instructs that the lip should run on an unblemished shaft area. Its guidance says a face seal may be a better choice when damage cannot be avoided by repositioning the hose while maintaining proper attachment.
That is a practical reason to discuss PSS on a refit. It is not permission to ignore a damaged shaft: the diameter, O-ring contact areas, alignment and overall condition still require assessment.
Tides has a useful service option
With the appropriate spare-seal carrier installed in advance, Tides allows a replacement lip to be brought into service afloat without uncoupling the shaft. This can be a meaningful advantage where that service arrangement fits the owner’s priorities.
PSS bellows work is planned around an out-of-water installation procedure. Its service approach suits an owner who wants to include seal maintenance in scheduled haul-out work. Compare the access and preparation each method requires.
Water supply and vessel details matter
SureSeal uses a pressurised cooling-water feed. PSS may use a vent on qualifying low-speed installations, while other applications require positive water supply. Neither choice should be made from boat type alone.
Tides also states that SureSeal is not recommended for engines with fewer than four cylinders. That makes the actual engine and driveline important information when comparing options for a smaller auxiliary installation.
When we would discuss PSS
PSS is worth considering when you prefer a face seal, want the dynamic interface off the shaft surface, or value the Type A and reinforced-bellows PRO choices. Send Luxfords your measurements and the reason for changing the current seal.
A good recommendation should also recognise a sound existing Tides installation and the value of its spare-carrier option. We compare the requirements of your refit so the decision has a clear technical purpose.
- Show the shaft and existing seal.
- Confirm the available room.
- Discuss cooling and engine arrangement.
- Compare the intended service plan.
Put the details to work.
Send your shaft diameter, stern tube outside diameter and vessel details. Luxfords will help you specify the right PSS assembly.
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