Friday, August 3, 2018
Wednesday, August 1, 2018
A Closer Look at the Rudder Post Cutless Bearing
I've been wondering why there's a cutless bearing, or what at first glance appears to be a cutless bearing, in the rudder post. Perhaps the yard's purpose wasn't additional support, but rather to aid in the installation of the rudder post tube. Specifically, they wanted to keep the post centered, within the post tube, while the post tube was being fiberglassed into the hull. Here's a picture of an installed post tube. It's 7" long (1" of that protrudes outside the hull), with a 2" ID and 2-1/2" OD).
The Fiberglass Post Tube Penetrates the Hull and is Fiberglassed Into it. A 7-1/2" x 2-1/2" Hose (Not Shown) Connects the Post Tube to the Packing Gland. The Metal Retainer, Seen above the Post Tube, Keeps the Lower Part of the Packing Gland From Moving When the Upper Part of the Gland is being Tightened.
I imagine the yard installed the rudder posts something like this. Drill a hole in the shoe and install the gudgeon.
The Shoe's Gudgeon (or Lower Rudder Post Bearing)
Next, mount the rudder post's upper bearing in the lazarette.
The Upper Rudder Post Bearing
Next, drill a 2" hole through the hull on a line between the upper and lower bearings.
Next, slide a 1-3/4" rudder post through the upper bearing and then through the hole in the hull. Before seating the post into the gudgeon, slide the post tube onto the post. Push the post tube against the hull and draw a line on the hull at the intersection of the post tube and hull.
Remove the rudder post and cut along the line on the hull. Now, finally, install the rudder post and post tube again. Slide all but 1" of the rudder tube into the hull and fiberglass it into to the hull. And there you have it, a perfectly aligned rudder post and rudder post tube.
A Piece of Rubber Emerging from the Rudder Tube
In conclusion: The rubber that we've seen coming out of the post tube for years isn't part of a cutless bearing. The rubber was there to make sure that there was a tight fit between the rudder post and the rudder tube during construction. Once the fiberglass had set the rubber was superfluous.
Dave Howell, Nellie D. 37VT63
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