[ArielM]

Guys,

Im hauling my 52'c this weekend to replace the packing seals etc. I also have some vibrations i want to try and resolve. I did an in water engine alignment and it seemed to be fine. I am planning to send my props in for balancing but i wanted to know the best way to check for strut alignment. Last time i checked the cutlass bearings they seemed to be in good condition. no uneven wear and i couldn't wiggle the shafts.

That said how do i check to see if the struts are aligned? I read in one article that if the struts aren't aligned i would see gaps between the shaft and cutlass bearing at opposite ends of the bearing. Seems simple and easy, but i was looking for a more "scientific" approach. IF the struts are not aligned do i align the forward strut or aft strut first?

Side note: My port shaft is much harder to free spin then the starboard shaft which is one more reason i think my struts aren't aligned.

[Capt J]

Originally Posted by ArielMiller

Guys,

Im hauling my 52'c this weekend to replace the packing seals etc. I also have some vibrations i want to try and resolve. I did an in water engine alignment and it seemed to be fine. I am planning to send my props in for balancing but i wanted to know the best way to check for strut alignment. Last time i checked the cutlass bearings they seemed to be in good condition. no uneven wear and i couldn't wiggle the shafts.

That said how do i check to see if the struts are aligned? I read in one article that if the struts aren't aligned i would see gaps between the shaft and cutlass bearing at opposite ends of the bearing. Seems simple and easy, but i was looking for a more "scientific" approach. IF the struts are not aligned do i align the forward strut or aft strut first?

Side note: My port shaft is much harder to free spin then the starboard shaft which is one more reason i think my struts aren't aligned.

Measure the gap between the shaft and the cutlass bearing all of the way around the shaft and on the front of the strut and rear of the strut. If you see a larger gap at the top of the cutlass bearing on the fwd side, and a larger gap at the bottom of the rear side, the strut would be angled slightly and not aligned......

[Loren Schweizer]

Done properly, a yard will laser-target your drivelines as well as check the shafts with a dial indicator.

[C4ENG]

When dealing in thousands of an inch sort of measurements, I would not recommend using natural sight in measuring, you need the right tools.
If your struts are out of line which sounds very possible, you do not move the strut to fix it. You have to align the bearing properly within the strut. I have seen where they have enlarged the strut bearing housing and then chalk fast the bearing back in properly. The vessel gained much needed power and got on plane much faster. It certainly takes some experience for that sort of work to do it right.

[ArielM]

If the struts are not lining up they bore out the inside of the strut so the bearing fits properly? If i am understanding you correctly that doesn't sound right at all.

I read pascoe artcile about strut alignment and he brings up a very good point that we struggle to align our driveline to the +- .005" and both engine and shafts are being held in place with rubber bushings which have a lot of give.

Dial indicator is a good idea to tell if the shaft is sitting correctly in the struts. What is the tolerance i am looking for ? place the dial indicator in-between the two struts and then also just as it enters the hull in the ER?

[captjohn22]

Unbolt the shaft coupling from the engine. If it is alinged properly the shaft will turn with little resistance.
The factory replaced a strut for me receintly after I hit a submerged something that distroyed two props and severly bent one shaft. I was the helper for this emergency repair. The mechanic loosely bolted the strut to the hull and using the jack bolts in the strut base, made fine adjustments until the shaft, without the prop on spun easly by hand. We carefully snugged the strut bolts checking for ease of rotation, then he mixed some epoxy to fill the gap in between the strut and the hull. She runs smooooooth now.

[captjohn22]

Originally Posted by captjohn22

Unbolt the shaft coupling from the engine. If it is alinged properly the shaft will turn with little resistance.
The factory replaced a strut for me receintly after I hit a submerged something that distroyed two props and severly bent one shaft. I was the helper for this emergency repair. The mechanic loosely bolted the strut to the hull and using the jack bolts in the strut base, made fine adjustments until the shaft, without the prop on spun easly by hand. We carefully snugged the strut bolts checking for ease of rotation, then he mixed some epoxy to fill the gap in between the strut and the hull. She runs smooooooth now.

PS: He realigned the engine after the strut work was complete.

[K1W1]

Originally Posted by ArielMiller

If the struts are not lining up they bore out the inside of the strut so the bearing fits properly? If i am understanding you correctly that doesn't sound right at all.

Hi,

I think he means that the bore for the bearing housing ( the hole in the strut)is increased in size to allow the bearing to be installed up or down at one end by the use of jacking screws/bolts and then the whole lot is set in place with Chockfast Orange.

ITW Chockfast Marine | Epoxy Grouts, Adhesives, Repair Products, Coatings

This is a very common practice in the big boat field so don't see why it wouldn't work just the same on a smaller shaft line.

[ArielM]

Ya i figured that is what he meant. I didn't think that it was practiced.

On my last boat they took they took the struts off and aligned it the way captjohn mentioned.

I will probably do the same thing. Take props off and unbolt from trans. loosen the struts until the shaft freely spins in the house and fill in the gap between the hull and strut with some kind of epoxy.

Captjohn,
Do you know what filler they used? The problem i would guess with a thick epoxy paste (like 3m marine filler) is that it dries too fast. Any idea exactly what filler is ideal for this?

[K1W1]

Originally Posted by ArielMiller

Any idea exactly what filler is ideal for this?

Chockfast Orange

[captjohn22]

Originally Posted by ArielMiller

Ya i figured that is what he meant. I didn't think that it was practiced.

On my last boat they took they took the struts off and aligned it the way captjohn mentioned.

I will probably do the same thing. Take props off and unbolt from trans. loosen the struts until the shaft freely spins in the house and fill in the gap between the hull and strut with some kind of epoxy.

Captjohn,
Do you know what filler they used? The problem i would guess with a thick epoxy paste (like 3m marine filler) is that it dries too fast. Any idea exactly what filler is ideal for this?

Sorry but I don't know. All I can tell you is he installed the epoxy around six PM and I went back in the water the next morning.

[C4ENG]

Originally Posted by ArielMiller

Ya i figured that is what he meant. I didn't think that it was practiced.

Yes K1 said it precisely. On the larger yachts the strut is usually rigid mounted and not ideal to tamper with, so the bearing is chocked-fasted in straight with the jack bolts. Of course this will not be the same route for every vessel with strut alignment issues.

[ArielM]

By riged mounted you mean molded in or welded in place? Im pretty sure on my boat i have 6 or so bolts holding the strut in place.

[Bamboo]

When I worked for Viking as a mechanic we had replaced some 60 boats' struts with new ones. We removed the old strut and filled in the retaining hardware holes. To place the new strut in the proper location a tight wire was strung between the engine room transmission/gear and the back of the bottom new strut (on larger hulls there was an intermediate strut) which was held in place by a special jack. On the wire was discs which were fit to the shaft size. When the discs were able to be inserted into the strut with little effort they were then centered and strut was in the proper place. The strut base which mated to the boats hull was coated with wax and filler was put on top (to the hull and strut) after finding the proper location and holes were drilled for the securing hardware. Then the strut was dropped, wax removed and placed back into position so that the bolt hardware installed and the discs still were centered. There may be a few details I've left out but we never enlarged the strut to accommodate moving the cutless bearing around. We did not use a lazer as some do- it's easy to fool the lazer with jack stand adjustments and the disc/wire method was more than accurate with proven results time and time again. I also worked for Liberty Yachts and set and installed several hulls with struts and engine placements with this method.

[dennismc]

target wire....