What’s been happening with the Gyrfalcon?

Well, a lot. Late last fall, we took the Gyrfalcon over to Port Townsend for some scheduled upkeep involving bearings, stuffing boxes, shafts, and a generator, and then we took off for New Zealand (by air, not by boat).  This blog is about the first part of the project: getting ready for repairs.

We’ve known for 10 years that there was an area of delignification in a floor timber, and that repairs would be necessary at some point.  Since it wasn’t too bad, we kept putting it in the category of Deferred Maintenance. Last spring, during a sea trial after some realigning of engines, Grant at Haven Boatworks noticed a bit of wobble in the port shaft. Blaise took a look at the lag bolts securing the stuffing box through the floor timbers, and, just with his hand, backed one bolt right out. That lag bolt was replaced with a through bolt and backing washers to get through the summer.

We scheduled repairs of the floors and associated bearings for the fall/winter, with Esther and Grant of Haven Boatworks overseeing aspects of the project.  Here’s a photo from last spring of the new bolt securing the stuffing box to the floor/floor timber, and a view from the aft aspect.

Boat terminology: What the heck is a floor timber?

The floor or floor timbers of a boat are the pieces of wood that hold the frames to the keels, support shafts, provide a base for engines, and undoubtedly perform many other functions. A good description of floor of a boat is at woodenboat.com https://skills.woodenboat.com/books/floor-timbers/ and a good photograph of floors in a sailboat can be found at  https://www.tobiaslunt.com/floor-timbers/. These illustrations might help you to visualize what is going on in our boat.

This is a photo of the Gyrfalcon (PATTON) under construction, showing floor timbers.  These photos are from a scrapbook that I found in the National Archives in College Park, MD.  I love the hat!

This is where the Gyrfalcon was built by Sagstad in 1940/41.  The location was Maritime Shipyards, Inc in Magnolia, Seattle.

Destruction

Boat upkeep always seems to start with destruction, and this project was true to form. We took a trip out of the country while Haven Boatworks (mostly Ushana, Claire, and Brendan) started breaking apart the powertrain. It’s probably best that we were gone, it sounds like it was a frustratingly slow process.

What came out of the boat

Propellers

Stub, intermediate, and tail shafts.

There are three shafts for each motor on the Gyrfalcon. From fore to aft, they are named as follows: the stub shaft (a short shaft just aft of the transmission in engine room), the intermediate shaft, which runs from the aft end of the stub shaft to just forward of the stuffing box, and the tail shaft, which runs from aft end of the intermediate shaft out of the hull to the propeller.  The shafts have a sacrificial metal lining at places of bearing wear.  It’s cool how they put these on–they heat the sacrificial metal, slip it on the shaft, and let it cool.  Our intermediate shafts are made of Tobin or Navy bronze, and are very resistant to sea water damage.  Here are photos of the intermediate shafts and the linings.

Cutless bearings and wobble struts

That’s not a typo–Cutless bearings are so named because they incorporate rubber linings so that the metal wouldn’t gouge the shaft.   We last replaced the cutless bearings right after we bought the boat, so they had enough wear that it made sense to replace while we had the shafts out.

Here’s a little more info if you’re interested in the history:  https://www.followingseas.media/blog/2017/1/30/name-that-bearing-1

Shaft log tubes (sometimes called shaft logs or stern tubes)

These are the tubes that encircle the shaft forward of where the shaft enters the hull. The inside of the tubes are contiguous with the sea. Our tubes were made of copper and original to the boat, and are getting replaced with fiberglass tubes. Here they are in place and after removal.

 

Babbitt bearings

A Babbitt bearing (invented by Isaac Babbitt in 1839), consists of a soft metal alloy that surrounds and supports rotating shafts. There are two on the Gyrfalcon – one at the forward end of the intermediate shaft, and one just behind the stuffing box on the aft (tail) shaft.  Each bearing has a surrounding housing.  The pillow bearings at the forward end of the intermediate shaft are a kind of Babbit bearing.

Stuffing box

Also called the packing gland, this is what keeps the ocean on the outside of the boat. Wax impregnated flax is wrapped around the shaft and allows a small amount of water to leak into the bilge forward of the stuffing box, keeping the shaft and stuffing box cool.

Enough for now.  We’ll show how everything is going back together in the next few blogs.