Prop shaft wiggled - pulled out of coupler - key slot corrupted

[Spring-Fever]

Need repair/general advice. (1984 Catalina 30')

Hitting reverse the other day -- clunk! -- prop shaft had loosened and pulled out of the transmission coupler. Locking screws were tight, and looking at female hole sets for locking screws....there was clearly imbalance/wobble/vibration. The key slot is also now "corrupted", it is worn and wider than it was. Holes for the set screws are also worn from the vibration.

Boat is in the water - and repair shop is backlogged 5-6 weeks before they can do a haul out.

Q: to get the process rolling, can I pull the shaft out entirely, and bring it and the coupler to a prop specialist for re-tooling?

Q: what else can I do, to get the ball rolling? Or should I just wait, get the haul out. Let the professionals replace the cutless bearing, pull the shaft, etc?


Boat in inoperable -- and won't be done until late May if I wait for the shop!! As you can tell from my name here - I have Spring Fever!!!

[Jubilee39]

Brave man to pull prop shaft in the water but I have seen it done. Just need an identical rod to take the place of the shaft going through the stuffing box. The shafy and coupleing could be remachined . I had a similar experience backing out of a marina in Singapore with no haulout facilities available. Cleaned everything up, new key and in my case a roll pin to go through the coupling. Some JB weld or equivalent to fill the gaps and it got me another couple thousand miles.

[AnsleyS]

Spring,


I suggest that you do it properly. Arrange for a haul out so that you can get a jump on the shop. You can pull the shaft yourself and then you will be ready for the shop when they have time or you can look for a local machine shop. When the shaft is out, replacing the cutlass bearing is easy and you can check your stuffing box. When it is all put back together adjust the alignment.


You will feel much more comfortable on your boat when you know that all that underwater stuff is good.

[nelly]

Originally Posted by Spring-Fever

Need repair/general advice. (1984 Catalina 30')

Hitting reverse the other day -- clunk! -- prop shaft had loosened and pulled out of the transmission coupler. Locking screws were tight, and looking at female hole sets for locking screws....there was clearly imbalance/wobble/vibration. The key slot is also now "corrupted", it is worn and wider than it was. Holes for the set screws are also worn from the vibration.

Boat is in the water - and repair shop is backlogged 5-6 weeks before they can do a haul out.

Q: to get the process rolling, can I pull the shaft out entirely, and bring it and the coupler to a prop specialist for re-tooling?

Q: what else can I do, to get the ball rolling? Or should I just wait, get the haul out. Let the professionals replace the cutless bearing, pull the shaft, etc?


Boat in inoperable -- and won't be done until late May if I wait for the shop!! As you can tell from my name here - I have Spring Fever!!!

Not sure I 100% understand - but is it possible for you to not have to replace the shaft?

I have seen two types of shaft couplings, the interference fit (what I have) and split, where you can tighten down on bolts to fasten to the shaft.

If you had an interference fit, to reuse you'll probably have trouble - but maybe you can order a split coupling and swap it out?

You can also easily machine a new key if you need to do that - and depending on your shaft material you can clean up the slot.

In neither case does the set screw or pin hold things together - it is simply to stop the shaft from spinning.

Pulling the shaft is the best thing you can do, I agree with that, it would be good to inspect the entire assembly. But, it does seem like you do have options if you do not want to or can't haul the boat right now.

[donradcliffe]

Just be aware that getting a new prop shaft can take weeks. Catalina direct has some supplier in Florida that stocks Catalina shafts with a taper on both ends, then has them cut the transmission end to the length you specify. You should pull the old shaft before you order to make sure that you get the length correct. I lost faith with them when they insisted Catalina had never used bronze shafts, while I was looking at one. If you want to do it right, get a new coupler and have the machine shop fit it and face it square.

[Spring-Fever]

@jubilee39 I like your style.....what's a "roll pin" through the coupling mean? (I'm leaning towards the pro's and haul-out, but if they delay another few weeks....think JB weld!)

[Spring-Fever]

@odonnellryan It is a single unit coupler, not "split". So I'd guess that's interference style. The set screws simply prevent it from spinning (not hold it together). And you're right, that old coupler probably has to go...and get replaced with a split style. I am pretty confident the prop shaft is fine - except that the key groove needs to be re-machined (if that's possible). DonRadcliffe's post scares me. If I wait to haul it, and only THEN the shop says I need a new shaft....I'd lose another month!?!?

[Tetepare]

Pull the shaft and take measurements. Go on Catalina Direct website and download the measurements page. They can fit shaft to a new coupler. Ships to you.

[Rumrace]

Many years ago two of us in scuba gear volunteered to pull a shaft and ram in a plug. Don’t do it!
We managed but was mayhem.
Get a pal with a small power boat. Lash it to the side of your boat and get him to drive you to some waiting crane cradle.

[Pete7]

Originally Posted by Spring-Fever

@jubilee39 I like your style.....what's a "roll pin" through the coupling mean? (I'm leaning towards the pro's and haul-out, but if they delay another few weeks....think JB weld!)

Some photos on here of a roll pin coupling. We have one and it needs care and the right sized punch to remove the roll pin with some oil.

If you can find one that fits and are willing to drill the shaft, you may not need to take the shaft completely out of the boat.

Coupling types and removal – Cox Engineering

[Cheechako]

Originally Posted by Spring-Fever

Need repair/general advice. (1984 Catalina 30')

Hitting reverse the other day -- clunk! -- prop shaft had loosened and pulled out of the transmission coupler. Locking screws were tight, and looking at female hole sets for locking screws....there was clearly imbalance/wobble/vibration. The key slot is also now "corrupted", it is worn and wider than it was. Holes for the set screws are also worn from the vibration.

Boat is in the water - and repair shop is backlogged 5-6 weeks before they can do a haul out.

Q: to get the process rolling, can I pull the shaft out entirely, and bring it and the coupler to a prop specialist for re-tooling?

Q: what else can I do, to get the ball rolling? Or should I just wait, get the haul out. Let the professionals replace the cutless bearing, pull the shaft, etc?


Boat in inoperable -- and won't be done until late May if I wait for the shop!! As you can tell from my name here - I have Spring Fever!!!

Just replace the shaft, it cant be that much and not worth messing around. Haul the boat, pull the shaft yourself, replace and have the prop checked for a bend. Check the strut (if it has one) and cutlass bearing for slop before you take the shaft out.
Do you have to pull the rudder on that boat to get the shaft out?

[jkishel]

Originally Posted by Cheechako

Just replace the shaft, it cant be that much and not worth messing around. Haul the boat, pull the shaft yourself, replace and have the prop checked for a bend. Check the strut (if it has one) and cutlass bearing for slop before you take the shaft out.
Do you have to pull the rudder on that boat to get the shaft out?

Also, check the engine mounts for excessive play. These can be sourced and replaced while you’re waiting to haul out. That might save you some time in the yard.

[Squanderbucks]

Probably just as important is what caused this issue in the first place. Unless you just prior hit something with your running gear there were warning symptoms you missed or ignored. Vibrations, engine moving on its mounts. The root causes need to be determined and fixed at the same time.
As far a jury rigging with JB weld. Only for emergency yo get you to the haul out.
Shaft needs to be pulled and sent to the prop shop and evaluated. If the jetway is buggered then you should most likely plan on a new one. As well as new coupler. Forget any attempts to “fix” the coupler.

Don’t forget to realign the shaft and coupler. If your mounts are loose or shot this will not stay aligned.

Some things on boats are more critical in how they are maintained and others might be left to function with less than perfect tolerances but engine/ prop shaft/ props are not one of those systems.

[Squanderbucks]

As for loosing another month. Welcome to boating. Two ways to face boating - prevention on your own pace and at convenient times or wait for problems and they always appear at the wrong and least convenient times.

I lost my summer plans one year when one of the fiberglass shaft tubes cracked and the boat started taking on water. Emergency haul out and decided to replace both shaft tubes after pulling water tank , fuel tanks and more. Two months on the hard and planned Bahama trip gone with the wind. Well next year no issues.

Hate to think what would have happened if this problem had occurred while in the islands. Likely all would have been lost.

Stuff happens.

[sinnerman]

My guess is that the shaft coupling has been removed before (with force). and is no longer a sliding/interference fit on the shaft. A "good" fit would require heating the coupling to allow it to "grow" slightly before sliding it onto the shaft.

Get a new shaft/coupling. As stated Catalina Direct sells shafts/couplings but you will need to send the the original shaft. (Pretty sure that ALL machine shops will require this). Here in Houston we have P&V machine who makes shafts.
[https://www.google.com/search?client...TF-8&oe=UTF-8]

Pointers:

Have the machine shop put the shaft / coupling as an assembly on a lathe and square it. This means making sure that the engine side end of the coupling is completely square/perpendicular (i.e. no "runout") to the axis of the shaft.

Make sure that the machine shop puts "dimples" in the shaft (small indentations) where the coupling setscrews will be seated.

Lock wire the setscrews after installation.

Replace the cutlass bearing when the shaft is out. You may want to convert to a dripless prop seal configuration at this time if you already do not have one.

Good time to check the condition of the engine mounts and replace if necessary.

Have someone with experience align the shaft/engine/transmission. Ask to watch. A GOOD mechanic will align the shaft first with the boat out of the water by making sure the shaft is centered in the stern tube (stern log) before making adjustments to the engine ...

My four cents.

Cheers