ISB-SA Series
Self-aligning Shaft Seal w/Intermediate Bearing
Description:
Upgrade your boat’s traditional bronze stuffing box with our premium ISB-SA Combo shaft sealing system. Superior reliability and performance combining the bullet-proof design of a traditional bronze stuffing box with the benefits of a water-fed “dripless” mechanical shaft seal. Cutless bearing housing helps reduce shaft vibration and noise.
Size and Selection: Scroll down for dimensions of the ISB mounting flange as well as the self-aligning packing nut.
Note: Custom Sizes including Metric are available by special order.
Questions? Give us a call at 207-422-6532
Safety First
Quality and Design Matters
The best marine shaft seals don’t have to be the most complicated to inspect, maintain, or repair.
Upgrade your boat’s stuffing box today with our ISB-SA self-aligning shaft seal with an intermediate shaft bearing (cutless bearing).
Our intermediate shaft bearing mounts in place of your boat’s stuffing box and the packing nut is free to self-align on the shaft by way of a heavy duty rubber hose.
Our ISB-SA Series (self-aligning) shaft seals offer exceptional durability and performance and are less likely to experience catastrophic failure compared to dripless shaft seals, mechanical shaft seals, and lip-type shaft seals.
Issues with “Dripless” Shaft Seals:
- There’s no rubber bellow to crack, rip or tear.
- There’s no rotor to slip on the shaft.
- There’s no carbon stator to crack or shatter.
- There’s no lip-seal gasket to fail.
- There are no set screws to loosen or slip.
- There’s no flimsy nylon hose barb fitting to snap off.
These failures are even more common in colder environments like New England, Canada, and the Pacific Northwest.
Don’t buy into the high-budget marketing campaigns and slick talk of well compensated sales representatives. Dripless shaft seals were never designed to be better. They were designed to be less expensive (cheaper) than shaft seals and stuffing boxes constructed with heavy duty marine grade bronze.
The cheapest parts aren’t always the least costly. Find out for yourself why more and more professional mariners and recreational boaters are upgrading to R.E. Thomas self-aligning shaft seals.
Selection and Installation:
Your Boat Deserves the Best:
Traditional Flange Mounted Stuffing Box: If your boat has a traditional flange mounted bronze stuffing box (flange mounted to a watertight bulkhead) our ISB-SA Combo unit should be relatively easy to install. The Intermediate Shaft Bearing (ISB) mounts in place of your stuffing box and the Packing Nut Assembly attaches to it by way of a rubber hose allowing the shaft seal to “self-align” on your boat’s propeller shaft.
Ready to Order?
Specifications and Size Guide:
Intermediate Shaft Bearing (ISB) Sizing Guide:

“SA Series” Stuffing Box Specs Sizing Guide:
