Trojan Boat Forum

Backing into the dock last night, the shaft slipped out of the tranny
with a bang, when returning to neutral

Prop stopped , but contacts rudder now.

Help.

Oooo. Not a good thing, that's all I know. Me, I'd get the boat out of the water and throw some money at my trusty marina mechanic. Tranny's don't come cheap, but it may be a coupling or other magic "thing" in there that makes everything work.

Thanks..


ps
Nice hardtop 26 you've got there...

I agree with randy, I'd get the boat hauled as soon as possible. Another guy at my marina had it happen to his F-26 flybridge and his boat almost sank as a result, happend to him at cruise. When I repowered a few years ago I paid $975 for a new borg warner 1:1 trans. Let us know how you make out
Matt

This won't fix your problem, but it might help you figure out what your issue is, and if you want to try to tackle it yourself vs. leaving it to the marina. I took the photo below in 2005 before I pulled the engine out of my F-26 for re-building.

The transmission coupling is part of the transmission assembly. Hopefully it is still in place. When properly assembled, the shaft coupling should be a tight press fit onto the shaft. This is important. The intent of the locking bolt is NOT to handle the torque of the engine. I think the most common issue is for the shaft coupling to loosen up on the shaft and the shaft slips out from the coupling. I don't know exactly why this happens. It probably has to do with a combintation of fatigue from the hoop stress, vibration and torque over time plus corrosion at the interface between a stainless shaft and a steel coupling. When I took mine apart, I had a bi@#ch of a time getting the 4 coupling bolts loose after years of corrosion, but with patience, penetrating oil, and a decent set of wrenches (not adjustable) I managed to get them off without resorting to a saw.

If the shaft comes loose from the coupling, there is nothing, (other than friction in the stuffing box, which is meant to slip on the shaft, and the rudder at the back of the boat) preventing the shaft from sliding right out thorugh the stuffing box. That's what causes sinking mentioned above.

As stated above, this is not properly fixable with the boat in the water. If you search this forum you will find postings describing drilling and tapping the coupling, sticking the shaft back in the coupling then cranking down on the coupling bolt and heading back out. The problem is very likely to recur with that approach. The proper thing to do is to haul the boat.

When the boat is out of the water, If the shaft slipped out of the coupling, you may be able to loosen up the packing nut and slide the whole shaft assembly right out the back. (Obvouisly you would need to remove the prop first.) You may also have to remove the rudder to slide the shaft out the back.

I don't think it's possilbe to properly press a new coupling onto the shaft inside the boat. Usually the new coupling is pressed onto the shaft at a machine shop and the coupling is then faced while on the shaft to make sure the face is perpendicular to the shaft so the shaft will run true without vibration. Hopefully the shaft didn't get bent, but if it did that's not a huge expense. I think I paid in the neighborhood of $275 for a new shaft & coupling back in '05. My original shaft was very badly pitted after 30 years in salt water, so I replaced it when I re-powered. (that price included pressing the shaft and facing the coupling. From there, it was a DIY installation.) Once you have your shaft out, you can roll it on a flat surface to make sure it's straight. If the shaft won't roll on a flat surface without humps, you need to replace the shaft.

Now you might want to sit down before reading the rest of the story, With the coupling properly mounted on the shaft, you cannot install the shaft in the boat with the engine in place. You have to lift the engine, up out of the way to slide the shaft through the stuffing box from inside the boat. You may not have to completely remove the engine, but it has to be lifted far enough out so you can slide the shaft into the stuffing box from the inside. You will definitly need to disconnect the fuel line, exhaust and cooling water. You might get away without disconnecting the wire harness. Since you are in there, this is obviously a good time to take a look at the stuffing box and the cutlass bearing.

Belive it or not, I did all this myslef back in '05, but that was off season, while I was re-powering so I had the engine out anyway. To a well equiped marina, this is probably not that big a job but I could easily see it running into $2,000 with hauling and launching fees. I would be very curious to hear how this works out for you.

Good Luck,
Chuck

chucka is the shaft tapered strate or keyed

Thanks, all .. for the feedback.
I will stay in touch...

( the shaft has a keyway on mine)

Thanks, chucka! That was a great description and the picture was really worth a thousand words! Either way it goes, it sounds like some buckaroos are gonna change hands!

Randy's question jogged my memory. I found the old shaft out in my garage tonight. It is 1" dia x 52-3/4 in long. The prop end is tapered. The coupling end is straight with a 1/4" keyway, about 3" long to engage the coupling. There are also two indents drilled in the shaft for two coupling bolts.

I didn't recall the keyway at the coupling end when I wrote about this last night.

Here is a link to the Glen-L website with info about shafts.
http://www.glen-l.com/weblettr/weblette ... shaft.html

Here is a web page showing the coupling and how it is keyed to the shaft.
http://www.getaprop.com/content-product ... ing_4.html

After seeing the key on the coupling I should re-phrase my comments about the press fit bearing the shaft touque. The key will support the torque between the shaft and coupling. I think the press fit should support most of the axial load in the shaft. If the coupling gets loose on the shaft, and you put her in reverse, the prop wants to pull the shaft right out of the coupling and the coupling bolts are the only thing left to prevent that.

ChuckA

Thanks

http://www.getaprop.com/content-product ... g_4_b.html

Might this eliminate need to hoist out the engine?

Yes a split coulpler would be the way to go ! I have them on my boat .

Mine did this about 2 months ago.
My shaft came loosewhile docking at the gas dock and slipped out far enough to tag my rudder as well. This is the second time that I am aware of. It happened to my Dad as well.
I ended up getting into the water with some flip flops on my feet and hung off the transom and, with my feet, worked the shaft back into the coupling then later after we got it into the slip My Dad and I drilled out and re-tapped the clamp bolts and put some thread lock in the threads.
What had happened on mine was when the shaft came out on my Dad years ago he re-tightened it but didn't realize that one bolt had rusted threads and didn't snung all the way down on the shaft, so really heonly had one bolt tightened down onto the shaft. So really, we are lucky it hung on that long.

If I were you, I would jump into the water and check out the potential damage to the rudder and prop. If there isn't any damage,work the prop back into the coupling like I did and have it tightened back down and make sure it stays this time.
Shoot, my Dad said if it comes back out again he will tack weld it into place. LOL! No kidding.... but funny.

Oh, pushing the shaft back into the coupling is not exactly easy but it can be done from the water, basically pushing the prop back towards the motor while working it back and forth with your feet.
Hopefully, you will be as fortunate as i was and didn't do damage tothe rudder or prop.

the fix cost me about $10 in case hardened bolts and then just some labor and sweat.

Thank you both.

I will keep you posted...