Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 02-09-2014, 01:43   #1
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Shaft log replacement in Malaysia - Singapore

Seeking knowledgeable advice re replacing the shaft log, and associated drive train installations and alignment.

The patient is a 1986 Jonmeri 40. Using a cute custom-made tool crafted by a local machine shop (photo 1) after 2 days of effort, finally got the cutless bearing out and removed the prop shaft. This revealed extensive corrosion at the in-board end of the shaft log tube, especially on the underside and under the retaining strap for the Volvo dripless shaft seal (photos 2&3). There are 1/8" diameter holes right through the stainless at the edge where the Volvo seats. Lucky we didn't sink the boat.

The boat is on the hard in Johor, Malaysia. Given the policies, realities and work force at this yard, this is going to be a DIY job. The yard will not allow us to bring in any outside (i.e., qualified) labour. Before I start blindly grinding away I need a lot of information, a plan, and confidence.

Here are the relevant (and perhaps irrelevant) details I can offer (attempts to get info from the manufacturer in Finland are in process, but so far frustrating):

The existing tube appears to be 50mm ID and 54mm OD, length approx. 30cm on top and 14cm on the bottom (cut at angle flush with hull). All other original stainless on this Baltic-built boat has held up beautifully so I presume it was top-quality high alloy 316 or 317. I now realize there was no cathodic protection for this tube. This boat design is non-bonded.

The Volvo shaft seal was last changed 4 years ago; the tube had some deterioration but looked serviceable. The seal had been previously changed in 2004. At that time there was corrosion along the 10-12mm inboard end of the tube. The corroded area was cut off and the Volvo seal was installed a bit further down the shaft on the still-intact remnant of tube.

The hull is solid fiberglass, approximately 35-40mm thick in this area. If there is a flange on the exterior hull (photo 4), it is under layers of vinyl ester and barrier coat applied after osmosis strip and repair in 2007 (New Zealand's Osmosis Solutions).

In addition to getting the new shaft log aligned and glassed in properly, the sequence and methods for installation and alignment (out of and in the water) of the following drive train elements need to be worked out:

- new engine mounts for the Yanmar 4JH2E, yet to be installed.
- there is a classic AquaDrive -- the seals on 2 prior AquaDrives blew out due to less-than-optimal engine alignment, but no problems for the last 9 years on this unit. I imagine that, at a minimum, the rubber mounting bushings should be replaced.
- adjusting the shaft coupling on the AquaDrive to correct the slight pulling of the shaft downward/to starboard that caused some uneven wear of the old cutless bearing.
- install new Volvo shaft seal.
- find and install new cutless bearing (unfortunately, 1 7/8" strut ID despite the 35mm shaft)
- the current prop shaft is 35mm diameter, 1.53M long. We are about to purchase a new FlexOFold, and we are very marginal on clearance under the hull and between the hub and strut. A new, longer shaft may be in order.
- new zincs on the shaft (finally, something easy!)

Oh, wait, and at some point here the rig (currently pretty slack) will be removed to install new electronics. Putting the mast up and retuning will tweak the hull.

So where to start? If anyone is willing to chime in on any or all of my questions, here is how I have attempted to categorize them:

1 - Pre-surgery prep: What do I need to measure and analyze, and how, before I start anything else? If I was fitting a new boat, the placement and alignment of the shaft log would be a given before getting to prop shafts, engine mounts, etc., so it seems my objective should be to make the replacement shaft log exactly as when this Jonmeri left the factory.

2 - Removal of corroded pipe: Should the objective be to remove the absolute minimum of surrounding fiberglass, or does that leave a tougher job for bedding the new tube?

3 - Sourcing new tube, fabricating flange (assuming I can't get one from the manufacturer). I don't think I have a good option other than again using a high alloy stainless with about 2mm wall thickness. I need the 54mm OD to fit the Volvo seal (of which I already have spares), and I don't have room for a larger seal (e.g., PSS style). Quality stainless should allow the largest ID for water flow inside the seal and around the shaft.

4 - Sequence for aligning everything - does this seem right:

1 - Install new cutless bearing in strut
2 - Install new bushings and adjust AquaDrive coupling (is this possible? how?) to true up prop shaft angle (machine shop has already confirmed that shaft is straight)
3 - Install prop shaft with new shaft log tube and Volvo seal threaded over shaft
4 - Center shaft log tube around shaft using shims, wedges -- I assume I want the shaft perfectly centered in the tube? That 50mm tube ID gives adequate clearance for any settling of the boat once it's in the water, or when the backstay is tightened, rig adjusted, etc.
5 - Does it matter at what point I install the engine mounts and do the on-land alignment to the AquaDrive?

5 - Glassing in/bedding new tube -- is this just a sideways thru-hull, or do I need to use other techniques and materials?

5 - How to provide cathodic protection to the new shaft log?

Thank you in advance,
Alii (Laura, sv ZEN)
Attached Thumbnails
Click image for larger version

Name:	20140829_174415.jpg
Views:	245
Size:	419.1 KB
ID:	87533   Click image for larger version

Name:	20140901_163331.jpg
Views:	277
Size:	406.7 KB
ID:	87535  

Click image for larger version

Name:	20140901_163552.jpg
Views:	211
Size:	419.6 KB
ID:	87536   Click image for larger version

Name:	20140901_171436.jpg
Views:	238
Size:	397.1 KB
ID:	87537  

__________________

__________________
Alii is offline   Reply With Quote
Old 02-09-2014, 04:00   #2
Moderator Emeritus
 
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
Re: Shaft log replacement in Malaysia - Singapore

Nice looking shaft pulling tool.

1 - Getting the old log out in "one" piece would be a worthy goal even if you have to take out a bit more hull. Have that pice as a template to make a new one will be very helpful

2 - Think about taking a piece of ply wood and cutting it like a "frame." The idea is to drill a hole through it that would pass over the end of the log on the forward/inside end. Then when you end up putting the new log in this "frame" on the inside of the boat will help you align the forward/inside end of the log and you fiberglass it back in.

3 - Figure out all the measurements you think useful to accurately position the forward/inside end of the log.

4 - The shaft puller looks like it could be useful to locate the outside/aft end of the log. You may end up dummy installing the shaft, aligning it using the puller tool, passing it through the frame on the inside and now you pretty accurately have the log positioned.

I will still hunt around here for machine shop type places that might be able to do the fabricating if you can't locate someone reliable in Johore.
__________________

__________________
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 02-09-2014, 15:19   #3
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

Thank you for the input. I think I get the frame idea, will mock one up with cardboard and post a photo. Don't know about using the tool-it is designed to push a 1 7/8" bearing, not hold a 35mm shaft or 54mm tube.

Sent from my GT-S7580 using Cruisers Sailing Forum mobile app
__________________
Alii is offline   Reply With Quote
Old 02-09-2014, 15:52   #4
Long Range Cruiser
 
MarkJ's Avatar

Cruisers Forum Supporter

Join Date: Dec 2007
Location: Australian living on "Sea Life" currently in England.
Boat: Beneteau 393 "Sea Life"
Posts: 12,828
Images: 25
Re: Shaft log replacement in Malaysia - Singapore

Why dont you just ditch it and get a new thru-hull log?
__________________
Notes on a Circumnavigation.
OurLifeAtSea.com

Somalia Pirates and our Convoy
MarkJ is offline   Reply With Quote
Old 02-09-2014, 15:58   #5
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

What? "Just ditch it?" "Get new?" Any helpful advice on how I actually do that in ay scorching hot DIY yard in Malaysia?

Sent from my GT-S7580 using Cruisers Sailing Forum mobile app
__________________
Alii is offline   Reply With Quote
Old 03-09-2014, 15:00   #6
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

Are there any solid reasons why this would be a bad idea: expose and cut back the inboard end of the SS tube, weld on a new length of tube, bury the joint in fiberglass. The tube is subject to vibration from the Volvo seal riding on the shaft and you wouldn't be able to inspect the weld for cracks. Are these fatal flaws to this approach?

Sent from my GT-S7580 using Cruisers Sailing Forum mobile app
__________________
Alii is offline   Reply With Quote
Old 03-09-2014, 17:22   #7
Moderator Emeritus
 
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
Re: Shaft log replacement in Malaysia - Singapore

If I interpret the pictures correctly the Volvo seal seals against the OD of the stern tube?

If you cut back the fiberglass covering of the stern tube to expose the metal tube I am still not not sure one could get a welder in there. But if you did get a piece butt welded on I would not worry too much about leakage becuase you would recover the shaft with fiberglass anyway.

However once you gotten the fiberglass off the inboard end, found and fabricated a bit of shaft, welded it on and resealed it you pretty much only saved your self reglassing the exit hole.

Probably worth doing it right and doing it once.
__________________
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 05-09-2014, 23:13   #8
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

Ex-Calif: is this the "frame" you had in mind?
__________________
Alii is offline   Reply With Quote
Old 05-09-2014, 23:15   #9
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

Trying again ...
Attached Thumbnails
Click image for larger version

Name:	1409980488011.jpg
Views:	161
Size:	39.0 KB
ID:	87802  
__________________
Alii is offline   Reply With Quote
Old 05-09-2014, 23:24   #10
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement - AquaDrive

I retain hope that some informative discussion may develop. Perhaps one narrow issue may catch more eyes:

The new engine mounts need to go in at some point, so I'm going to do it as soon as possible, before installing the new shaft log tube, to rule out any possibility that aligning the engine on the mounts could somehow alter the alignment of the shaft between the coupling - shaft log - strut. (This will delay the rebedding of the tube a bit -- while the forward port mount is out I need to remove and rebuild the raw water pump, and it will probably be 2-3 weeks for the new shaft to arrive.)

As I noted in my first post, the shaft does seem to pull slightly downward to starboard at the strut. Do I correct for this at the AquaDrive coupling? How?
__________________
Alii is offline   Reply With Quote
Old 05-09-2014, 23:41   #11
Moderator Emeritus
 
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
Re: Shaft log replacement in Malaysia - Singapore

Yes that's what I envisioned for a template. I am not familiar with the Aqua Drive maybe someone familiar with it will chime in.

I think it is wise to replace anything that can affect alignment prior to replacing the tube and trial/mock fitting it all up. This will alert you to any need to shift the log alignment.
__________________
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 06-09-2014, 03:32   #12
Registered User

Join Date: Nov 2013
Location: Slidell, La.
Boat: Morgan Classic 33
Posts: 1,102
Re: Shaft log replacement in Malaysia - Singapore

Looks like that shaft log has to come out, there is no hope of welding a stub on without creating more problems than you solve.

There appears to be some kind of crevice corrosion issue or electrolysis issue (maybe from the assortment of metals making up the Aquadrive?), I'd seriously look at replacing the metal tube with a fiberglass one. Here is a link to a supplier:

Shaft Log/Rudder Post Housing - Centek | Fisheries Supply

Regarding the replacement itself, how qualified are you on fiberglass work? That is the most crucial thing, the removal and reglassing are relatively straightforward, providing you have the right tools and use the right materials in the correct applications.

Without being there and seeing your complete setup, only generalizations can be made. Providing the Aquadrive is mounted in the right place, it, along with the cutlass bearing, could be used as a guide to align the new shaft log.

My (theoretical) plan would be to, remove the old log, leaving the original hole in the hull as is as much as possible. Slide the shaft into the new cutlass bearing,.Slide the new shaft log (unchamfered if fiberglass) onto the shaft, slide the shaft thru the hull, attach the coupling to the shaft and then the coupling to the Aquadrive. You could then use the shaft itself to ensure that the log is in the right place when you glass it in. (You will of course probably have to remove and replace the shaft several times to grind the hole to fit but careful measuring and taking your time go a long way in something like this)

If you go with a fiberglass log, you chamfer it after installation.

Again, this is very general, but I hope you get the idea.

As for making sure the aguadrive is in the right place, a good book describing engine alignment is a good start. Just use the Aquadrive output flange as a proxy for the gearbox output flange and do what you have to do to align it as described for a traditional engine/gearbox. While one of the aquadrives claims to fame is the ability to absorb misalignments (and I believe that's on the engine side anyway), it's always better to have everything as close to perfect alignment as possible.

The good thing about changing the shaft log is that you have the opportunity to ensure that the cutlass bearing, log and aquadrive are in alignment. After that is correct you can pretty much do whatever you have to to get the engine in the right place.
__________________
jimbunyard is online now   Reply With Quote
Old 06-09-2014, 05:46   #13
Senior Cruiser
 
atoll's Avatar

Cruisers Forum Supporter

Join Date: Mar 2010
Location: gettin naughty on the beach in cornwall
Boat: 63 custom alloy sloop,macwester26,prout snowgoose 37 elite catamaran!
Posts: 9,311
Images: 75
Re: Shaft log replacement in Malaysia - Singapore

personally if doing this job i would use fiberglass tube to replace the old ss log.

cut the laminate around where the ss tube exits the hull from the inside,leaving the eliptical hole through the hull and then grind either side of the hull laminate to provide a good bonding surface.

once you have got your new fiberglass tube fitting fairly loosely in the eliptical hole where it exits the hull,set up the alignment between the p bracket and the outboard end of the aqua drive using the prop shaft with spacers in the glass tube to hold the tube centrally on the propshaft.

then once happy with alignment of aquadrive,glass tube log and p bracket,use epoxy glue/filler mix to hold the glass log in place,once set,remove propshaft .

then progessively laminate the new shaftlog in place with epoxy ,cloth and filler inside and out the hull,untill required thickness of laminate and structural integrity is achieved.

on the engine side of the aqua drive the alignment is not so important as they can cope with about 4-6 degrees of mislignment.
__________________
my catamaran building project updates http://www.cruisersforum.com/forums/...36#post2502136
atoll is offline   Reply With Quote
Old 06-09-2014, 06:50   #14
Registered User

Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 609
Re: Shaft log replacement in Malaysia - Singapore

It looks like this isn't a great application for stainless. Maybe from sitting in stagnant water when not in use it gets oxygen deprived...

On my boat the log is bronze, I replaced it because it's 50 years old, but it looked beautiful. It made me wonder why bronze _shafts_ are all but impossible to get now.

The shaft log has threads on each end that thread into the stuffing box on the inside of the boat and the stern bearing housing (holds the cutless) on the outside of the boat. Both stuffing box and stern bearing house have flanges that seat against the hull/deadwood. I have no separate strut. That stuff was available from T Norris marine in the UK.

In your case it looks a lot simpler, the modern approach is no deadwood and a permanent tube glassed to the hull. I agree you should use a fiberglass log, I'd think you could just remove your old stainless tube, clean everything out, and pop in the new fiberglass tube with a load of 5200. Assemble your drivetrain and you'll almost get the alignment for free, assuming the end points (strut and shaft output coupling on aquadrive) we're aligned to begin with, although I'd take steps to ensure everything is aligned.

I'm not sure what fiberglass work is necessary other than gluing in the new tube, the structure of the thing is already in place (that fat fiberglass tube you see that's glassed to your hull.). Then again, I don't really know how your boat is built.
__________________
chris95040 is offline   Reply With Quote
Old 06-09-2014, 20:38   #15
Registered User

Join Date: Jul 2014
Location: Philippines
Boat: Jonmeri 40
Posts: 145
Re: Shaft log replacement in Malaysia - Singapore

Thanks everyone for the input. We aren't fiberglassing pros for sure, but have fussed with this boat for 17 years, lived aboard full-time for 13+, 2 prior refits, have closed old (3) and installed new (3) thru-hulls, and perhaps most relevant have changed out our portlights twice, the last time closing in and fairing the deck house before cutting out smaller holes for smaller frames. We are using all International products (AUS and UK formulations) and have a variety of cloth weights, woven roving and chopped mat. And the West manuals and other how-to guides.

The Centek fiberglass shaft log that will accommodate my shaft and Volvo seal is only 1/8" thick. Is this thick enough? This only matters for the part of the tube exposed between the seal and interior lay-up, but there could be no worse place to have a crack.

Another question re fiberglass logs -- is standard antifouling (we use Ultra) enough to keep marine growth from choking them up? Am I wrong that stainless would/should inhibit growth better, allowing more water flow to the seal? One thing I'll say about the old stainless tube, we never had a fouling problem in it (clean the bottom at least monthly) and didn't paint it with antifouling.

As for what caused the corrosion in the old shaft log, it hasn't been exposed to stagnant water. We are usually on the move, or most recently on a 4-point mooring. We have motor-driven refrigeration and rely on the alternator to charge our batteries (no wind, only small token solar) so every day we run the motor at least twice and in gear (even if on the mooring). The tube is not in contact with the AquaDrive or with any other metal on the boat.

Thanks again for the input,
Laura
__________________

__________________
Alii is offline   Reply With Quote
Reply

Tags
Malaysia, men, Singapore

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Old Log will be moved to opencpn.log.log PHD1026 OpenCPN 26 19-05-2015 14:01
Crew Available: Anyone moving from Malaysia to Indonesia? Or around Malaysia? MarieJ Crew Archives 1 19-03-2014 17:46
Strut, Shaft, Shaft Log, Engine Alignment KestrelBuck Engines and Propulsion Systems 24 04-04-2011 00:14
Need Good Broker Reference in Thailand / Singapore / Malaysia Area dingoman Dollars & Cents 4 17-02-2011 10:50
Marinas in Malaysia Near Singapore mcvouty Marinas 3 19-08-2009 18:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:44.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.