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Old 09-17-2018, 08:00 AM   #146
SeahorseMarineDD54201
Veteran Member
 
City: Zhuhai
Country: China
Join Date: Jun 2018
Posts: 71
Quote:
Originally Posted by twiisted71 View Post
How long are your stern tubes? Just to make sure we're talking about the same thing....when you say stern tube, its the section of tube that the packing gland/stuffing box (traditional or dripless) attaches to, correct?
And on your boat does the cutlass bearing go in this tube or does your boat have a strut supporting the distal end of the shaft just ahead of the prop?

I'm just not able to picture in my head having a stern tube (aka Shaft log) so long that it needs a support bearing between the cutlass and stuffing box. How do you keep the water from ruining the support bearing. or are you using two cutlass bearings (one at the end and another farther forward?

Our shafts were never more than 6' long and we'd mark the shaft at 2' and 4', place supports under it at those points, shim those until best alignment of shaft and transmission flanges, f'glass or weld shaft log in place, slip cutlass bearing and surrounding tube onto shaft, fit up strut pieces and tack weld together, remove strut/cutlass assembly, remove cutlass and finish weld strut assy and reinstall. We only had to install a support bearing once on a boat that had a 1.25" shaft. Our 2" shafts never needed a support/whip bearing. The support bearing though was forward of the stuffing box and was a simple pillow block bearing mounted to a stainless crossmember between the stringers.
Sorry for the late reply. Prepared for then survived the worst recorded typhoon in Hong Kong.

Post #127 has a diagram of the assembly. The Fiberglass Stern Tube is 3.34 meter (about 11 ft). The boat has a long keel so the entire Shaft Log/Stern Tube/Shaft is within the keel, except the two ends. The Stern Tube is epoxied within (and is not the same as) the steel Shaft log (Seahorse does not want the steel shaft log to be exposed to salt water), the Cutlass Bearing and Whip Bearing are placed inside the Stern Tube, then the Shaft rotates within the bearings. Yes, the Shaft Seal (PYI make, I believe) is fastened to the Stern Tube at engine end. As the boat has a long keel, there is no strut.

There is a water injection point on the Shaft Seal, to push water through the (forward) Whip Bearing, then the (prop end) Cutlass Bearing.

Not sure I fully understand your assembling procedure. It sounds like you align the shaft, then build in the surrounding structure. Seahorse aligns the Stern Tube, epoxy in place, then insert the shaft.
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