Struting!

As I march toward the engine install I decided it was time to get the strut reinstalled and lined up with the stern tube because once the engine is in, access to that area becomes infinitely more difficult.  I didn't expect it to be a particularly difficult job since the base of the strut fits neatly into a pocket in the hull and should line up to the stern tube perfectly.  Or so I thought.

Just to be sure though, I decided to test fit it first and run a string from the inside of the stern tube to the aft side of the strut to make sure it was spot on. I 3d printed 2 'centering jigs' to hold the string right in the center of the strut and in the center of the stern tube so I could visually see if everything was lined up.  For the strut I printed a 1" diameter plug with a hole in the center and for the stern tube, I did the same, but with a 1.25" plug.

I dry fit the strut and then installed the jigs and string in the forward end of the stern tube in the cabin and the aft end of the strut.  It looked perfect to me, but what I failed to do was take a set of calipers to make sure the string on the forward end of the strut was perfectly centered... It wasn't.

Looks perfect to me, but looks are deceiving!

Installed centering jig in the stern tube.

 

Since I thought everything looked good, I proceeded to fully bed the strut with 3M 4200 (along with the 4 bolts secured at the aft end of the engine bay.  I went home in blissful ignorance that afternoon and printed a collar to center the shaft in the stern tube to make sure it all fit properly the following day.  

On my lunch hour the next day, I brought the shaft over, inserted the 3d printed collar into the stern tube and then inserted the shaft from the cabin.  Then I jumped down below the boat and found to my horror that the shaft was WAY too tight in the strut (and cutlass bearing).  Dejected, I went home and started researching how tight a shaft should be in the cutlass bearing.  When I re-shafted my Alberg, I didn't remember any difficulties, but the shaft was much shorter and the cutlass bearing is installed directly in the shaft log.  Harrumph! 

After work, I went back to the boat and upon closer inspection, I could see that the shaft was pinching on the top of the aft end of the strut.  This meant that forward end of the strut needed to be lowered.  Looking at the photos I took of the string, it became clear that while the string looked like it was dead center at the front end of the strut, it was slightly lower (~1/16") than it should be.  So the strut would need to be shimmed on the front side.  It was probably shimmed originally, but when I bought the boat, I only had the strut in a box of equipment.  Based on the pocket in the hull, I made the incorrect assumption that it would all fit perfectly.  

Fortunately, I hadn't used the 3M 4200 fast cure and was able to pull the strut off fairly easily once I unbolted it and clamped a 2x4 onto it to provide leverage and break the bond.  I cleaned up the pocket and strut and returned to my shop to find some good shim material.  Thinking that the offset was about 1/16" (0.0625), I cut 2 pieces of G10 plate the width of the strut and taped them into place and refitted.  This time, I skipped my fancy centering jib and just inserted the shaft and voila, it slipped through the cutlass bearing perfectly and I was able to rotate the shaft by hand without any noticeable stiction.  Yay.  I pulled the strut again a rebedded it with another round of 3M 4200 and bolted it back into place.  The shaft once again slipped through the strut and bearing with ease and rotated freely.  

So the job is 95% done, but I can't quite cross it off the list yet because I need to give the 4200 a week or so to fully cure and then clean it up and fair over the base of the strut in a manner similar to the photos I have of the boat prior to the strut being removed.  

Much better!

Shaft centered in shaft log with collar