On Oct 27, 2022, at 12:13 AM, David Vogel <david.vogel@...> wrote:

Thanks Mark.

OK, cancel that request!

Success, the bow-thruster is out!!

Method: Using the chain-wrench and it's 1m extension, I repeatedly rotated the motor assembly back and forth through about 70º either side of the nominal position. I did this for about two hours, applying copious amounts of PB Blaster. At the end of this, I could use the chain-wrench without the extension to rotate the the motor assembly. I did not use short-sharp forces at any time ("primum non nocere"; firstly, do no harm). However, at the end of this, I was still unable to get any downward movement on the torque-tube.

I then lowered the BT partially and, using a line secured to the vessel tie-downs at the bow, tied the bow-thruster down in a partially extended down position - trying to keep everything in-train (in-line). And then, raised the bow-thruster a little using the normal raising mechanism, just enough so that there was some tension on the tube-motor interface, but not overly straining the raising mechanism. And then, using the chain-wrench on the bottom of the motor (again, not needing the extension), repeatedly twisted the motor assembly about the tube, again, about 70º each way, applying liberal amounts of PB blaster. Finally, some downward motion on the torque-tube. In about 1-1/2 hours of incrementally re-tensioning the tie-down, raising the bowthruster a little, twisting the motor assembly, I ended up with the bow-thruster separating completely from the motor assembly. Once the holes for the securing bolts were visible, the last 5mm happened suddenly.

(I had placed a hose-clamp around the torque-tube, as you would do if in the water to prevent the BT falling out and sinking to the bottom; as well, I ran an extra line from the BT up to the deck to prevent the BT falling all the way to the ground, in the event that the hose-clamp should fail to do it's job. But the hose-clamp held fine, even though the torque-tube was well slippery with PB blaster. I had the hose-clamp placed around the bolts that secure the threaded brass inner to the fiberglass torque-tube, and really tightened it up.)

Will be looking for that BOSTIK Never Seez - no-one here has heard of it. Any known alternatives?

Thanks.

David
SM#396, Perigee
MCM, NZ





<Line Up.jpeg><Line down.jpeg><BT out.jpeg>