Hi does anyone know some one other than porters that can check and repair shafts in Sydney
Porters can't fit me in and slipping next week thanks

Google "boat shaft repairs sydney" brings up Cassellmarine on the Central Coast who may be able to fit you in but they may not want to travel - you can take the shaft up to them maybe.

Also try JBC Yacht Engineering Kirribillli 9188 0825

www.facebook.com/JBCEng/

Hi kurt.
What is the problem?
Bent, corrosion, worn thread ,shaft or keyway?
If you are up for a new shaft or even a repair, you don't need to deal with a marine engineering co. I just googled "stainless steel turning Sydney" and came up with a bunch of places. Give it a go.
Gary
www.google.com/url?q=https://www.curraneng.com.au/cnc_turning.php&sa=U&ved=2ahUKEwjuuPOCwaP-AhWjpVYBHZ1HCy8QFnoECAoQAg&usg=AOvVaw0K8weHBidrZOXpJ0ughU-J I'm


www.google.com/url?q=https://www.alsopengineering.com.au/machining-c11oy&sa=U&ved=2ahUKEwjuuPOCwaP-AhWjpVYBHZ1HCy8QFnoECAkQAg&usg=AOvVaw2JAuErnUax7pRSgfNxri-K

Thanks guys good tip garry jbc will have a look for me
I think its a bent shaft or coupling not true on the shaft
I have vibrations and when doing the alignment it's set perfect until I rotate the shaft 180degrees then its way out

Boat I'm on ATM just had new shafts installed by Oyster Cove Marine Port Stephens two weeks ago but that's probably too far for you to go. My friend was happy with the work.

Hi Kurt.
Not lining up after 180 degrees rotation would indicate a bent shaft.
Question is ,why.
Any shop with a decent press will straighten it.
What shaft diameter are we looking ?

Gary

You need to check shaft run-out and the coupling face run-out to isolate the error .
180 deg way out ? How much is way out and where is it measured from.

would have preferred to have the boat hauled in port Stephens have heard good reviews of oyster cove but don't want to do the trip the way it's is
The shaft is 1 1/2 inch
I have tried checking with a dial indicator while on the boat but couldn't get a good enough reading on the shaft although I confined its not comming from the gearbox flange there is no run out there
the alignment was set to 0.005 flange to flange then once the shaft was turned 180 one of the thicker feeler gauges was fitting in can't remember which one exactly
I do wonder why I dont think ive hit anything or atleast didn't hear it
it all started around the time my gori prop blade pins started coming out which when I dived on the boat to check on things i found the pins comming out
Have a fixed 3 blade on it now which didn't change the vibration
Slipping next week I will report back on the findings
Thanks for all the help
Kurt

It may be that the shaft flange coupling is not running true. It's often the case that couplings are fitted to the shaft straight from the shelf ,where as the correct procedure for fitting would be to have the alignment faces of the coupling re-machined whilst using the prop shaft that it's going to be fitted to as the turning mandrel .

Boats back in the water did the alignment on the weekend shaft was slightly bent and coupling was not true to the shaft
Went out for a test yesterday now running perfectly reached Max rpm 2800 at 9knots with no vibrations
Thanks seabreezers

HI Kurt
Goo to hear you got it all back together.
Where and how did you get the shaft straightened?
It might be useful information to others in the future.

gary

Hi Gary
Jbc enginering said they would do it
My slipway in avalon took it to a local engineer to do it not sure who but I know there in monavale
Possibly state enginering
Not sure how It was straightened cost me $340 to straiten and machine the coupling they also fitted a locking bolt on the coupling so the shaft can't slip out
Happy with the result worst case would of been a new shaft the shaft was much longer than I thought at 2.2m

Many years ago I had the shaft from my fishing boat at Porters for a service. While I was there one of the blokes straightened a yachts shaft. He held it in one hand and struck the shaft once with a hammer. Job done!

I guess its a skill acquired no special tools needed
I have herd before never touch a good shaft with a hammer

Excellent article here;

www.repairengineering.com/shaft-straightening.html#:~:text=Spot%20heat%20shaft%20straightening%20uses,remains%20relatively%20cool%20and%20solid.

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Ramona said..
Many years ago I had the shaft from my fishing boat at Porters for a service. While I was there one of the blokes straightened a yachts shaft. He held it in one hand and struck the shaft once with a hammer. Job done!

I watched the engineer at Eden slip do something similar a few years ago. New shaft for a TRV that was bent in transit. A little heat here and there and a few taps with a largish ball pein hammer. Job done.

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kurt88 said..
I guess its a skill acquired no special tools needed
I have herd before never touch a good shaft with a hammer

Yeah your right, very un professional to straighten a bent shaft with a hammer. Doesn't surprise me from porters.,, your going to bruise it and damage it when it's totally unnecessary to do so. Even a lead or copper hammer will leave bruises and a steel ball pein would be unforgivable. So called professional tradesmen with no idea.

A press.
Controlled pressure.
A hammer might be good enough in a pinch (remote location) other than that it is a bodgy job.

gary

Took the Collaroy harbour ferry bent prop shaft to ADI Bendigo Feb 2001 after it ran up onto the bricks Manly - worked out the plastic deformation back the other way needed so that when unloaded it would come back and be straight - lent on it with 83tonnes and straightened it. Final skim proof machining done.

This is getting my interest. On my AWB a miss hap has occurred owing to misjudgment of the tidal flow and the prop came in contact with a submerged part of the training wall, as a result the prop has some damage, I've been nursing her, anything over 1000rpm she gets a real vibe up. (Threats of live MOB are part of induction) I will remove the prop and fix it next scheduled slip, what's the chance of the shaft being bent ???? 3" bronze shaft, pics to assist with guessing ( no underwater shots )

Superb boat.

Don't want to get into thread drift but below is another project early 90s diagnosing best engine revs to run a small coastal chem carrier with one prop blade tip damage and associated prop unbalance as well as associated prop water flow issues - 4 blade prop. Able to nurse it for 6 months before next scheduled docking by avoiding revs which excited vertical and lateral hull girder lowest frequency bending modes. A year later did a similar project on a Japanese collier to get it from Sydney to Japan with a whole blade missing - albeit originally 5 blades. It was a slowish trip for them but they got there.

Would expect your shaft to have a high probability of a bend or bow between the cutlass bearing and stern tube. What is the prop damage? If a chunk has been knocked off one of the 3 blades then this will cause similar unbalance and flow issues as in this case. If there is only blade tip bend to one, then lesser unbalance and water flow issues will occur. If blade tip bends to all 3 then this could be the sole course of the vibrations. Am sure you will but would check any damage to the cutlass bearing, p bracket and associated fasteners ("double" p bracket as it goes down to the keel deadwood as well as up to the hull), other.

If you have access to a vibration monitoring kit with spectrum analyser in it prop unbalance will show up at higher magnitudes at 1x prop speed, bent or bowed shafts and associated misalignment at 2x. Blade tip bends if on all blades will show up as higher blade pass frequency component - so number of blades times shaft revs. If only 1 blade tip bent then probably higher 1x.

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woko said..
This is getting my interest. On my AWB a miss hap has occurred owing to misjudgment of the tidal flow and the prop came in contact with a submerged part of the training wall, as a result the prop has some damage, I've been nursing her, anything over 1000rpm she gets a real vibe up. (Threats of live MOB are part of induction) I will remove the prop and fix it next scheduled slip, what's the chance of the shaft being bent ???? 3" bronze shaft, pics to assist with guessing ( no underwater shots )

Mine had the same skeg, rudder and propeller. I had my shaft out a couple of times over a 22 year period. Mine was SS with sleeves. I took the shaft and propeller to Porters for a tune up for the prop. It's a long shaft you should make a cradle for it to carry on a tray top truck. Have some friends to help removing it to keep it straight. My shaft was straight I just had them replace the sleeves. Your bronze shaft would be worth a few bob. Might be best to keep that to yourself!

Cheers fellas, damage to all three blade one more so than the others. Will check cutlass bearing etc when on the hard, no issues there when hauled out oct 2021. I repacked the stern gland last time out and there's some scoring on the shaft, but for the couple of hundred hrs a year she does I was happy to let that ride, my idea was if the prop will come off with the rudder on I was going to dodge dressing the shaft, now this bent shaft thread has me wondering. ps all the running gear, bow fittings etc are bronze except the rubbing strips are aluminium, someone must of swiped them when she was laid up that's 80' of 2"x 1/4" I'm not surprised

With damage to all 3 blades this could reduce the probability of shaft bend or bow. Such al 3 blade damage will cause unbalance as well as bad blade pass frequency vibrations. The other thought is that the 2 relatively long shaft spans - cutlass to outer stern tube, inner stern tube to gbx - could lead to shaft whirling issues. Which is lateral and vertical natural frequency motion of the shaft as you would be aware of. Vibrations resulting from these would usually only occur around their natural frequency modes and not at all revs - have you had this issue? Are you able to dive and do a shaft run-out check with a bit of timber stuck in between the shaft and hull 1/2 way between the cutlass bearing and outer stern tube? Secure it hard up against the hull and rotate the shaft to see if separation occurs? Just a thought.

Before the incident going ahead at all speeds was ok I wouldn't say smooth,( Detroit hard mounted in a 60 yr old timber boat ) when it was put astern with a good amount of revs ( some students get a bit excited) you could feel a shake if you were in the stern, I put that to the prop needing attention back then, good idea with the bit of wood for a gauge, I will give it a go next time I'm diving