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dhgolembiewski
Last seen: 2 months 1 week ago
Joined: 1/25/09
Posts: 4
Engine mounts and vibrations

I have a '96 MKII and experience a lot of vibration at certain rpm. My mechanic says its bad engine mountss. I think it might be the cutlass bearing. Any comments?

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deising
Last seen: 7 months 1 week ago
Joined: 11/3/08
Posts: 1351

The cutless bearing only comes into play when the prop shaft is spinning. Bad motor mounts would exhibit the vibration while the transmission was in neutral and the prop shaft still. That should help you sort it out.

Also, when you say a 'certain RPM' I hope you don't mean a low idle speed. Many, if not all, of our diesels will vibrate heavily at low RPM. My tach is fairly accurate (it has been checked with a light strobe) and I need to be above 800 RPM for the vibration to diminish.

--

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

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stu jackson c34
Last seen: 1 year 4 months ago
Joined: 12/3/08
Posts: 1269

What engine do you have? Four or three cylinders?

There are two parts to engine mounts: the connection to the engine and the connection to the stringer or engine bed.

Have you checked the lag bolts to the stringers?

--

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

wvanravenhorst
Last seen: 8 years 8 months ago
Joined: 12/9/09
Posts: 1

How do i replace the cutless bearing on a C36 from 1990. The bearing is mounted in a strut and is not fastened by bolts. An other question is how to remover the shaft. Do i need to remove the rudder?

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LCBrandt
Last seen: 2 months 2 weeks ago
Joined: 6/26/07
Posts: 1282

wvanravenhorst,

First, we welcome you to the Forum. This thread isn't specifically about cutless bearings, but it's a good first step as you're new to the Forum. Here's what you should do, either one or both of the following:

1. Use the Search capabilities on the Forum pages to find all postings on the word "cutless", or "cutless bearing." There will be quite a bit of information here, saving you from having to wait for an answer.

2. Go to the C36IA homepage, click on the Technical tab, then click on the Maintenance tab. Then scroll down a bit to find an excellent article related to cutless bearing removal.

C36IA Association Members have access to a *loaner* cutless bearing removal tool. The Association's tool loaner program has saved Members many, many thousands of dollars...just one more reason to become a part of the C36IA. The three-year membership costs as little as $60 (just 20 bucks per year) and includes a free Tech Notes CD containing a huge library of technical articles, boat and system manuals, and other valuable reference info.

Glad to have you here.

--

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

ProfDruhot's picture
ProfDruhot
Last seen: 4 years 9 months ago
Joined: 2/8/09
Posts: 354

You know, you guys have got me wondering if I should just go out and buy some new motor mounts for my engine. I have had a good friend of mine who recently had to repalce his motor mounts on his 1999 MkII because they failed. They can't be too expensive (famous lst words huh, especially on a boat). Does anyone have an idea of what I am looking at? Then I am wondering if I could install them myself.

--

Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B

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Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Glenn, Tom Sokoloski posted that he had great luck with Vetus K75 mounts his boat like mine has the three cylinder M25XP engine. Your boat will take a different mount I believe and I also think that someone posted some data about that install. It is certainly a doable job, you will of course need to reallign your shaft after replacing the mounts.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

Bill Colmer's picture
Bill Colmer
Last seen: 6 years 4 months ago
Joined: 6/28/09
Posts: 15

I am also considering replacing my engine mounts. The existing mounts are for the original engine which has been replaced by a Yanmar, but whoever did the installation left the original engine mounts in place. The vibration/noise is so bad you can't even talk on the radio if the engine is running.
I went to the engine manufacturer's site and found the proper engine mounts for MY engine. They cost $67 each, four are required. I would think you could follow the same process and hopefully have the same luck in finding the correct engine mounts for your engine.

[I]A note and an opinion:[/I] We have the technology to minimize engine vibration and noise. If you were to spend the same amount of money on a car as you spent buying your boat you would expect the engine to be quiet and in many cases almost impossible to tell if the engine was even running. This should be possible in a boat, too. I do not understand why modern vibration technology has not yet been brought into sailboats.

--
1988 Catalina 36 Hull #862
"Heart of Gold"
Steve Frost's picture
Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Bill,

Vibration isolation has become a high science in late model automobiles, they also have the benifit of extremely smooth running engines. Damping the vibrations of a diesel especialy a three cylinder diesel are far more challenging. Engine mounts can do wonders, the early Yanmars were known to break many of an engine mount due to there extream vibration.

Some of the newer technology softer mounts will help the newest automotive technology uses hydraulic dampers some are even active using computors to control them but, on our boats the best mounts will just somewhat reduce the problem. The issue is the mounts only dampen vibrations on a lateral axis since the prop shaft is directly coupled to the engine and is fixed to the hull. The only good way to get dampening in all axes of the engine would be to decouple it from the hull.
This would require a hydraulic or electric drive system or installing a costant velocity joint between the engine and the shaft. Constant velocity drive systems are out there but they require more space than is available on our installation and would also require the coupling or CV joint to be solidly bonded to the hull. I had looked at this system but it would appear we are short obout four inches on the my engine with the three cylinder engine, I would expect the M35 installation to be tighter yet.

If weight and cost were no object, removing the existing engine and installing and replacing it with a large gen set driving and electric motor like some of the new hybrid cats would work. Having near silent motoring is attractive but, I will consider it out of my budget.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

LCBrandt's picture
LCBrandt
Last seen: 2 months 2 weeks ago
Joined: 6/26/07
Posts: 1282

Can anyone identify the vibration damper in this photo I took on a C36 some years ago? And can anyone speak to its effectiveness, cost, a suggested source, etc?

Attachments
--

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

Steve Frost's picture
Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Larry,

I do not recognize this one. R&D make a coupler somewhat like this and is sold by West Marine. Vetus sells several couplers and CV systems, when I looked a couple years ago I had only noted there CV systems. They now have several couplers that can make up for shaft misalignment up to two degrees. It would also be a doable install on our boats. This will not decouple the engine from the shaft but may get rid of some of the resonant vibration that make your fillings fall out. On the up side these resonant vibrations may make the big barnicles fall off when motoring.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

Maine Sail
Last seen: 3 months 2 weeks ago
Joined: 2/26/10
Posts: 315

It's a Drive Saver. IMHO and experience they don't do much unless you hit something then they may protect the gear box. The version from PYI is slightly better but the coupling from Federal is even better than the PYI..

--

-Maine Sail

https://www.marinehowto.com/

 
pierview
Last seen: 2 days 4 hours ago
Joined: 9/27/09
Posts: 478

wvanravenhorst,

As posted, you can get the tool on loan to do the cutless bearing yourself. However, I don't like to do stuff myself where if I make a mistake, such as under the boat, its hard to redo. If I screw up the cutless bearing, I've got to rehaul, etc.

I had it done on my 2002 C36 a couple of years ago by a tech for about $260.... worry free. Where are you located? If your in my area, I can give you a contact if your interested in having it done.

--

Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

wilfbradbury
Last seen: 7 years 9 months ago
Joined: 6/22/08
Posts: 25

On our boat I replaced the flexible exhaust connecting pipe between the water lift muffler and the exhaust pipe from the manifold with one of the after market silicon blue flexible hoses. This made a terrific reduction in low rpm vibration.

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LCBrandt
Last seen: 2 months 2 weeks ago
Joined: 6/26/07
Posts: 1282

Wilf, yes...that hose is called a "hump hose."

This is the hose connects the exhaust riser to the muffler. The hump hose topic came up recently in another thread. Using a hump hose in place of the all-too-common black (stiff) exhaust-type hose certainly does make a big difference in vibration level.

--

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

dhgolembiewski@... (not verified)

I have had the cutlass bearing checked and determined it is not the problem.

The engine is a 4 cylendar Universal Westerbeake. It will vibrate in low rpm or even at about 1500 rpms.

I also will be checking the injectors to improve the millage.

dhgolembiewski@... (not verified)

[QUOTE=ProfDruhot;3439]You know, you guys have got me wondering if I should just go out and buy some new motor mounts for my engine. I have had a good friend of mine who recently had to repalce his motor mounts on his 1999 MkII because they failed. They can't be too expensive (famous lst words huh, especially on a boat). Does anyone have an idea of what I am looking at? Then I am wondering if I could install them myself.[/QUOTE]

I got a quote of $1,000 to replace the engine mounts.

LCBrandt's picture
LCBrandt
Last seen: 2 months 2 weeks ago
Joined: 6/26/07
Posts: 1282

dhglowembewski,

You don't provide enough information for us to comment. If you click UserCP in the blue band upper left hand corner of this page and set up a complete signature with all the information about your boat we could offer more targeted suggestions. At the moment we don't know what model, how old the boat, or any other details to make valid recommedations.

We want to help, but you'll have to help us help you.

--

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

impag
Last seen: 1 year 3 months ago
Joined: 7/3/08
Posts: 39

This winter I replaced the engine mounts and cutlass bearing in our 1994 C36 #1339. I have the M35 AC engine. Initially I ordered the mounts from the local distributor to be sure I had the correct mounts. Although the Vetus mounts have received rave reviews, neither of the mounting holes are slotted.
Upon receiving the recommended mounts, I recognized that these were the same mounts, Bushing DF-100, available for much less from Go2Marine.com, $36 each. The difference between the Bushing and the original mounts was that the original had two slotted holes for engine alignment adjustment whereas the Bushings only have one slotted hole. According to the local rep, the difference should not matter. I will find out when the boat goes in and the mechanic attempts the alignment. I also noticed that the original aft port motor mount holes oriented that mount such that the aft outboard corner extended over the edge of the stringer slightly. I observed this on another C36 listed on Yachtworld. Has anyone else noticed this kind of misalignment?
The prop was reconditioned to a type 1 class last season. The Duramax cutlass bearing is available from Jamestown distributors for $40. Removing the prop seems to be the biggest issue in replacing the bearing. I removed the prop before signing onto the queue for the club tool. I don't believe high stress situations are one of AARP's approved vacation activity.

--

John & Kathy Impagliazzo
s/v Pooka
Jamestown, RI
1994 C36 TR #1339, M35AC

deising's picture
deising
Last seen: 7 months 1 week ago
Joined: 11/3/08
Posts: 1351

[QUOTE=impag;5132]... I removed the prop before signing onto the queue for the club tool. I don't believe high stress situations are one of AARP's approved vacation activity.[/QUOTE]

I would have loved the chance to do that, but here in SW Florida, my boat is in the water and being used just about every week of the year (except every two years she is hauled for several days to do bottom work).

--

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

impag
Last seen: 1 year 3 months ago
Joined: 7/3/08
Posts: 39

Duane,
Were you able to replace your cutlass bearing?
John I--
s/v Pooka,
C36 #1339
Jamestown, RI

--

John & Kathy Impagliazzo
s/v Pooka
Jamestown, RI
1994 C36 TR #1339, M35AC

jmontani
Last seen: 2 years 1 month ago
Joined: 7/19/07
Posts: 143

I think this thread started as engine mounts and went to other areas but I do have a question about engine mounts and the M35AC engine.

My 1996, 14yrs this month, has 715 hours and the port side rear mount is going. Going through this I will replace all 4 mounts.

My question is will the Vetus mounts work with the same footprint holes as the OEM Universal mounts or do they require new holes to be drilled into the stringers? From what I have read, the Vetus mounts seem to work well.

If they will work (no new holes), is it the Vetus K 100, K 75, or K 50 mounts that should be used for the M35AC engine?

Thanks for any help.

--

Jack
Solstice
Hull #1598
1996 MKII/TR/FK - M35AC - 3 Blade MaxProp
Lake Texoma

www.texomasailing.org

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TomSoko
Last seen: 3 weeks 4 days ago
Joined: 2/15/07
Posts: 978

Jack,
Yes, the Vetus mounts will work without drilling new holes. You might want to elongate one of the two holes in each of the mounts to allow for adjustment. I don't know the detailed specs for the K50, 75, and 100, but several C34 owners tried the K50 mounts on their M25s, and determined that they were too soft. I used the K75s as replacements on my M25XP, and they were awesome. My guess is that the K75s would be good for the M35, too. You might try calling Vetus and asking their opinion.

--

Tom Sokoloski
C36/375IA Past Commodore
Noank, CT

jmontani
Last seen: 2 years 1 month ago
Joined: 7/19/07
Posts: 143

Thanks Tom. Looking on line I was able to find the Vetus mounts for not much more than the OEM.

According to the OEM distributor the M35AC had two possible stud sizes on the engine...1/2 or 5/8ths. So another measurement required.

Love the cross-over year of an engine. 1996 was the last year of the M35AC.

--

Jack
Solstice
Hull #1598
1996 MKII/TR/FK - M35AC - 3 Blade MaxProp
Lake Texoma

www.texomasailing.org

deising's picture
deising
Last seen: 7 months 1 week ago
Joined: 11/3/08
Posts: 1351

[QUOTE=impag;5138]Duane,
Were you able to replace your cutlass bearing?
John I--
s/v Pooka,
C36 #1339
Jamestown, RI[/QUOTE]

Not sure how I missed this question, John, but I was not. You need to get the prop off first and no amount of heat, prop puller tension, and mallet tapping would make it budge. I finally concluded that the cutless bearing was not that worn after all and left the problem for another time with better advance preparation.

--

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

jmontani
Last seen: 2 years 1 month ago
Joined: 7/19/07
Posts: 143

In talking with a distributor, there were two types of mounts possible for my engine that Catalina could have used. They were 4" and 5" configurations. See attached.

My boat used the 5 inch x 5/8th stud mounts. Looks like I might be stuck with the OEM mounts since the Vetus mounts are only 100mm (almost 4 inches).

Additional Information:

I did find that R&D Marine (through PYI) makes a 5" mount. Has anyone used these mounts? They are less than the OEM but still much more than a 4inch mount.

Also, the Westerbeke mounts do not provide deflection specs.

Does the attached spec on the R&D mount seem to be in line? The part number from R&D is 800-062.

Attachments
--

Jack
Solstice
Hull #1598
1996 MKII/TR/FK - M35AC - 3 Blade MaxProp
Lake Texoma

www.texomasailing.org

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nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

Hi All,

I have been watching this thread with interest for some time, in fact, since I acquired Fresh Aire II May last year. She has always had quite severe vibration at higher revs and also a terrible clatter at sub-1,400 rpm. In the past I have received some good advice from our experts on this forum.

She is a 2001 C36 with Universal M35B engine and 5" engine mounts. The rear mounts had collapsed and were starting to rub on the stringers.

As it is now approaching summer here in Sydney and you are all preparing to winterize your boats in the US, I decided it was time to address this problem.

The symptoms have been:

• Serious clatter at idle speed, especially when engaging reverse and forward. Really embarrassing when rafting up!

• Reasonably smooth running up to 2,200 rpm (the boat was refitted with its original 2-blade fixed prop when purchased as the previous owner’s 2-bladed feathering prop was so out of balance).

• Increasing vibration after 2,200 rpm till the whole boat shakes itself to pieces at full revs (3,050 rpm). This is NOT the case in neutral - all is well through full rev range.

Lots has happened, some good, some not. Here goes - if you want specific part numbers let me know....

1. Because of the "can of marbles" clatter in idle from the transmission, the damper plate between the motor and the gear box was replaced with an R&D flexible damper as part of the purchase by the previous owner last year. This fixed some of the "marbles". But the clatter returned quite soon afterwards.

2. Commencing last week, replaced engine mounts with R&D 800-024 (as described in previous post on this forum) as they were the only 5” mounts with the appropriate ratings that we could find. They are correctly rated but were terrible when installed. The vibration through the boat was chronic at idle speeds, only diminishing after 1,000 rpm. Do NOT use these mounts, they are far too stiff.

3. Swapped out the R&D mounts for Vetus K75’s. They are sweet and smooth from 800 – 3,050 rpm. Good move and highly recommended. Had to drill 4 new mount holes as they are 4” mounts (not 5”) and thus moved the whole engine back by over ½”. I did not want to move it forward as I wish to add extra insulation to the engine cover - see below.

4. Replaced ALL bearings on exit side of gearbox and added another clutch plate shim. This has had a dramatic affect in eliminating the “can of marbles” and the transmission is now nice and quiet. I understand that a special lubricant was also used to keep things quiet.

5. Fitted a new R&D flexible coupling between the gearbox and prop shaft. This added further damping, but am not sure how much of an additional affect this has actually contributed. It does provide full galvanic isolation for the prop shaft, however.

6. Fitted a new “Volvo type” rubber shaft seal which has a bearing built in – this is shorter than the previous drip-less seal – the space was needed as the engine had moved back and the R&D flexible coupling was now taking up more space. The prop shaft now spins extremely freely.

7. Installed a Kiwi Prop as set up by the suppliers. It dropped the max revs to 2,500 rpm in forward (and gave unbelievable reverse thrust – 3 knots at idle!)

8. Everything at idle and lower revs is now sweet and smooth. But above 2,200 rpm still THAT vibration.

9. Thus, removed prop shaft, had the face of the coupling machined and had a very slight bend machined out of the shaft.

10. At the same time, re-pitched the prop by an expected 600 rpm benefit to get the full rev range. Also checked that each blade had the same pitch and that the prop was balanced.

11. Engine now revs to 2,700 rpm max and still not 3,050 (!!) and THAT vibration is still there increasing from around 2,400rpm. The lesser pitch now means I need to use the higher revs to get the same speed from the prop.

I now have a wonderfully smooth and pleasant boat below 2,200rpm and after that it is horrible – it simply gets worse right to maximum revs. The whole boat shakes, the binnacle and wheel shake and it is not useable at the higher revs.

We are out of ideas, the mechanic now suggesting:

• Replace the prop shaft altogether as he thinks there may be “high spots” (not sure why as it has been machine lathed)

• He feels this may be a C36 endemic problem, namely, a harmonic vibration set up at higher rpm (in which case I will re-pitch the prop for lower rev operation).

Any comments from fellow C36’ers? Do you have a high rpm vibration with the M35B engine (above 2,200 rpm)? Any ideas why the motor will not reach its full rpm even with the prop re-pitched (it does reach full rpm in neutral). There is some white smoke from the exhaust at high rpm. Any chance that the motor has a problem under load and this is causing the vibration and not being able to reach full rpm (although it does rev smoothly right through in neutral)?

SOUND INSULATION

The next phase of the silencing Fresh Aire II project is to totally encapsulate the engine room with VyBar 20mm insulation (see [url]http://www.acoustica.com.au/vybar.html[/url] ). I am told it is magical stuff (not cheap) and people swear by it. But I would first like to get the vibration issue sorted.

Any assistance would be most appreciated.

Thanks,
Nigel

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
deising's picture
deising
Last seen: 7 months 1 week ago
Joined: 11/3/08
Posts: 1351

Nigel,

I wish I had time to ponder your dilemma more, but I can say that our 1999 model C36 does NOT have any significant vibration from 1000 RPM up to maximum (3,000). [I have calibrated the tach and it is pretty close over the whole range.]

There is one narrow RPM range where I get some harmonic vibration in the cockpit lids, but I just avoid that very narrow speed range.

You problem sounds serious, but it is not normal for our boats. Best of luck finding a solution.

--

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

BudStreet
Last seen: 1 year 4 months ago
Joined: 9/4/09
Posts: 1127

We have an M35A and it's cruise according to the manual we have is 2100 to 2400 and anywhere in there it is sweet. It is also fine from idle to 1500 RPM, but between 15 and 1800 rpm it vibrates, though not real badly. Once the engine hits 2000 rpm it just settles down and sounds totally different than at lower revs, I suspect they've balanced it for that rpm range and it likes it there. So it doesn't seem endemic with 36's.

If I was you (thank you big guy that I'm not what a nasty problem) I would put a new shaft in and cutlass bearing as well if that hasn't been done, then you have replaced pretty much everything from the back of the engine out. If it still shakes at high rpm, then I would strongly suspect the engine is acting up under heavy load. Could it be that the injector pump is having issues at the top end? Talk to a good diesel guy (scarce item where I live, hopefully you have some around there) and see what they say.

Good luck fixing this!

nbpatterson's picture
nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

Hi,

Thanks for the posts so far. I will look at the injector pump. Is this something that would show different characteristics under load at full revs versus under no load at full revs?

I did forget to mention that the cutlass bearing was also replaced. A friend of mine has further suggested taking the prop off and running the motor through its full rev range to isolate the prop being the problem.

The other area I was advised to look at is the cutlass bearing support to check that this is not out of alignment.

Please keep the posts coming!

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
BudStreet
Last seen: 1 year 4 months ago
Joined: 9/4/09
Posts: 1127

Nigel, I'm not a motor expert but the fuel system responds to load. It has to on a diesel which is un-throttled. The governor/injection pump kick in more fuel as load is increased on the engine to maintain engine speed. If for some reason at high RPM under load the governor wasn't doing that or the injector pump wasn't able to supply the extra fuel then the engine would do something odd. I'm guessing it would start to miss really badly.

Bad injectors could do this too but I would expect that would show up at all speed ranges not just at higher RPMs.

Taking the prop off might tell you something but it wouldn't put any load on the engine so it might mislead you.

Steve Frost's picture
Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Nigel,

Good accounting of your issues, I would agree with Bud in regard to replacing the shaft. I do not understand the machining they did to take out the high spots. You would normally have the drive couplings machined to make sure they are flat and runnig true to the shaft. If the shaft has a bow in it I would not know how to machine that out, taking down the high spots reduces the outside diameter and weakens the shaft.

I too would look at the strut and make sure it is not loose where it attaches to the hull, mine had worked loose due to a worn cutlass bearing and was replaced when I purchased the boat.

You should be able to adjust your Kiwi prop for full RPM and I believe the manual calls out a specific number of turns on the stop screw for a given RPM increase. I love my Kiwi, it has great reverse thrust but, could use a different reverse stop as the pitch is far too coarse in reverse. Kiwi props have a reduced hull clearance, ten percent of the diameter is the norm and the Kiwi offers a bit less than that, if you prop is overpitched and you are not getting full RPM the prop could be cavitating and causing your vibration. I would address the RPM issue before changing the shaft. If after readjusting your prop if you can still not get full RPM you may need to increase your max fuel flow as you may not be developing enough power to get full RPM.
If your pitch stops are already turned all the way down talk to John Blundel at Kiwi and I bet he would send you a set of shorter blades that will increase the RPM if yours are adjusted to the limit.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

Maine Sail
Last seen: 3 months 2 weeks ago
Joined: 2/26/10
Posts: 315

Nigel,

Your issue sounds a lot like shaft whip. How much over hang is there between the strut and the leading edge of your prop? It should be 1 times shaft diameter max. Many feathering and folding props move thehub and blade mass further aft and at high RPM it gets the shaft between the strut and shaft log swinging like a jump rope. By adding a flexible coupling you also potentially add to any shaft whip issues by moving the shaft even further aft with more overhang after the bearing than you really want.

A proper installation of a Drivesaver type unit should include shortening the shaft to maintain the 1 X shaft over hang guidelines. Of course the manufacturers never tell you this stuff because when you add up the cost of the unit and machine shop expense, you'd never do it. I have solved a number of drive line issues by removing Drivesavers and flex couplings..

You should also be able to attain max rated RPM at wide open throttle with a clean bottom and prop. Over propping is not good for the engine. Here's what Universal recommends for the M-35B.

[B][I]
Universal recommends a propeller that will allow the
engine to turn 3000 RPM underway at full throttle [/I][/B]

[B][I]From ABYC P-06

6.5.5.4 The distance between the forward end of the
propeller hub and the aft end of the last strut bearing shall
be limited to one shaft diameter.[/I][/B]

And one other consideration most don't take into account:

[B][I]6.5.5.2 If a non-conductive flexible coupling is used, an
alternative means of grounding the shaft must be provided. [/I][/B]

If you can run your engine up beyond 2400 RPM in neutral without these vibration issues there is a very high likely hood that the issue in the drive line. If you get this vibration while in neutral than it's more likely in the engine, injector, fuel pump, timing etc. etc...

--

-Maine Sail

https://www.marinehowto.com/

 
Steve Frost's picture
Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Main sail, you make a good point and it may be reinforced by the fact that during the instalation of the new engine mounts Nigel indicated that the engine was moved aft to accomodate the installation. In addition an isolation coulpling was installed, this too would move the shaft further aft and may exacerbate the whipping issue. Nigel did state the vibration problem was present prior to these modifications, this may negate my thoughts related to the Kiwi prop cavitating as well.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

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TomSoko
Last seen: 3 weeks 4 days ago
Joined: 2/15/07
Posts: 978

Nigel,
I also agree with Bud. I've heard from several sources that you can never get a prop shaft back to true once it is out. Machine shops will argue with that assertion, but don't listen. Don't know if you have a bronze or SS shaft, but I'd suggest getting a new SS or Aquamet shaft, and have the coupling machined to be perfectly square to the new shaft.

--

Tom Sokoloski
C36/375IA Past Commodore
Noank, CT

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nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

Hi Everyone,

Thanks for the fantastic input! I will forward this off to the Catalina mechanical expert who is doing the work for me.

If whipping is a real issue to look out for, then we would have certainly exacerbated this with the new installation as there is a considerable amount of shaft length showing aft of the cutlass bearing. This would also have the effect of altering the position of the prop in relation to the hull creating a larger gap between prop and hull - not sure if this potentially increases or reduced risk of cavitation (same goes for moving the prop closer to the rudder).

Considering each slip costs me around $500/3 hrs in Sydney Harbor, the trial and error method of resolving this can become an expensive process!

The shaft is SS and there is no obvious indication of the cutlass bearing post being out of alignment - but still need to check this closer. Also not too sure how it was straightened/machined - will look further into this.

I still need to get my head around why when the Kiwi prop manual says I should get 300-400 rpm increase per 1/2 screw pitch adjustment, I only got around 250 rpm increase for 3/4 adjustment. Perhaps it has to do with constrained fuel flow as Steve mentioned.

Once again, I reiterate that there is no vibration at any rpm whilst in neutral - the tach has been calibrated and the engine reaches its rated 3050 rpm smoothly.

Will keep you posted as to the outcome as I am sure we can all learn something from this.

Nigel

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
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nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

Hi Everyone,

An update as to where I now am in resolving the vibration issue.

Last week I replaced the prop shaft with a new 316 Stainless steel shaft cut to ensure only 1" overhang aft of the cutlass bearing, and another $600 later just for the slipping (groan!).

This has made a significant difference - the vibration is all but gone, and it is totally smooth up to 2400rpm. The original shaft did not appear bent on their lathe but then we also suspect it may have been a softer grade SS creating whiplash. The shaft was also shortened by 38mm (about 1 1/2"). This too could have contributed to the issue. The moral here: if you think there may be a problem, there probably is a problem and just do it!

The maximum neutral revs is now 3050 - no vibration.
The maximum in-gear revs is 2600 - very slight vibration still, but quite acceptable.

At 2600 rpm black smoke appears suggesting the prop is over-pitched, but tried changing the pitch before and made little difference at top end (could this be a Kiwi-prop characteristic?). The prop is heavily pitched in reverse.

Kiwi-prop performance (all test with a newly anti-fouled hull):

Neutral idle rpm: 800 (no vibration since changing to Vetus mounts)
Neutral max rpm: 3050 (no vibration)

Forward idle rpm: 800 - 2.3 knots SOG (no vibration)
Forward cruise rpm: 2200 - 6.6 knots SOG (no vibration)
Forward max rpm: 2600 - 7 knots SOG (very slight vibration)

Astern idle rpm: 750 - 2.8 knots SOG (a challenge backing into marina initially)
Astern max rpm: 1500 - 6.2 knots SOG (transom starting to take in water!)

Increased sailing speed by around 0.5 - 1 knot SOG, especially in light breezes.

Furthermore, other than what I understand to be the characteristic forward direction gearbox chatter till around 1200 rpm, the rest of the drive train is quiet, especially so in reverse. I will live with the 2600 rpm max revs in forward and back off slightly so there is no black smoke.

The Kiwi-prop is perhaps not the greatest prop on the planet, but at 1/3 the price of competitors, it does a pretty good job.

My next job in making friends with the NVH (Noise Vibration & Harshness) project - I have chosen to not call it a "war on NVH" as modern wars appear to be unwinnable! - is to install 20mm VyBar sound insulation right around the engine bay. This product is specifically designed for marine environments - see [url]http://www.acoustica.com.au/vybar.html[/url] - and has excellent first hand reviews.

Will let you know how this works out once completed.

And just in case you thought I did no sailing, last weekend we had a wonderful day on Sydney Harbour in winds in excess of 25 knots! This is very typical for this time of year.

Happy sailing and I hope that the above dissertation is of some assistance to those trying to resolve vibration issues.

Nigel

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
LCBrandt's picture
LCBrandt
Last seen: 2 months 2 weeks ago
Joined: 6/26/07
Posts: 1282

Thanks for the update. But 6.2 kts in reverse??? At 1500 RPM??? Holy cow! One small slip of the wheel and the prop shaft would have been toast, I suspect. You're a brave soul, mate. Nevertheless, I wish I could see a video of it. May be a hint of future boat design...canards instead of rudders. (Steve Frost, here's the seed of your next April 1 article.)

As for the NVH Project, will you be documenting the sound levels Before and After with a sound meter? Please think about writing this up for JibSheet, as there are many others who are very interested in this project. I, for one. Take lots of photos, please.

--

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

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Steve Frost
Last seen: 5 years 5 months ago
Joined: 12/14/07
Posts: 788

Larry,

I have been a Kiwi convert for some time and have posted several comments about the prop since installation.

The reverse thrust is impresive with this prop and yes you can whistle along at near hull speed in reverse (hang on to that wheel like your bank account depended on it). If I were to suggest one change to this prop it would be a rework of the the reverse pitch stop to give it a bit less pitch in reverse as it really loads up the engine due to its high pitch setting. You need to set the idle up on the 25XP to keep it from killing the engine when put in reverse, this can be more excitement than you desire when coming into a dock too quickly and the engine quits when you hit reverse.

The prop called out by Kiwi for the C36 is a bit larger in diameter than many props. John Blundel of Kiwi has sent me a set of shorter blades that I will install at the next haul out, whith them installed I trust it will increase reverse RPM and since the forward pitch setting with the larger diameter blades is very low I susspect that I can increase the pitch setting with the shorter blade and get the same performance. The increased tip clearance my quiet the drive train down as well. Though I have no complaint about this issue with the larger blades, the diameter of the Kiwi prop installed does exceed the ten percent of diameter hull to tip clearance. This rule is to prevent cavitation and noise generated by to low a clearance. Again noise has not been any issue with this prop.

--

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

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stu jackson c34
Last seen: 1 year 4 months ago
Joined: 12/3/08
Posts: 1269

Steve makes some very good points. In addition, please note that diesel engines require only two things to run: air and fuel. The reason the engines are so noisy, in addition to the mounts, is that they are essentially OPEN to the cabin. That, in addition to the measly blower hoses, is where they get their air. If you "locked them up" to avoid the noise, you'd have to find another way to get air to the engine.

--

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

impag
Last seen: 1 year 3 months ago
Joined: 7/3/08
Posts: 39

After having the prop reconditioned, replacing the motor mounts and cutlass bearing, installing the hump hose and having the engine aligned, the vibration still persisted to a lesser degree. At the Newport Boat Show I happened to sit down to lunch with one of the gentlemen who taught the engine seminar at Hansen Marine. The conclusion was that the vibration was due to cavitation of the original 3 bladed prop. The vibration frequently occurs while in a maneuver.

[QUOTE=impag;5132]This winter I replaced the engine mounts and cutlass bearing in our 1994 C36 #1339. I have the M35 AC engine. Initially I ordered the mounts from the local distributor to be sure I had the correct mounts. Although the Vetus mounts have received rave reviews, neither of the mounting holes are slotted.
Upon receiving the recommended mounts, I recognized that these were the same mounts, Bushing DF-100, available for much less from Go2Marine.com, $36 each. The difference between the Bushing and the original mounts was that the original had two slotted holes for engine alignment adjustment whereas the Bushings only have one slotted hole. According to the local rep, the difference should not matter. I will find out when the boat goes in and the mechanic attempts the alignment. I also noticed that the original aft port motor mount holes oriented that mount such that the aft outboard corner extended over the edge of the stringer slightly. I observed this on another C36 listed on Yachtworld. Has anyone else noticed this kind of misalignment?
The prop was reconditioned to a type 1 class last season. The Duramax cutlass bearing is available from Jamestown distributors for $40. Removing the prop seems to be the biggest issue in replacing the bearing. I removed the prop before signing onto the queue for the club tool. I don't believe high stress situations are one of AARP's approved vacation activity.[/QUOTE]

--

John & Kathy Impagliazzo
s/v Pooka
Jamestown, RI
1994 C36 TR #1339, M35AC

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deising
Last seen: 7 months 1 week ago
Joined: 11/3/08
Posts: 1351

Wow, John, that was quite a lot of work and expense only to partially fix the problem.

The prop cavitation would seem to be still just a theory unless and until you replace the prop with something different and the problem goes away. There are so many of us with the original 3-bladed prop who don't have vibration issues that it makes me wonder about that theory, however.

In any case, best of luck to you.

--

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

impag
Last seen: 1 year 3 months ago
Joined: 7/3/08
Posts: 39

An interesting point about the vibration experienced is that when it occurs, it is right under my feet when standing at the helm. I also found it exists to a lesser degree over the transmission compared to what I feel over the dripless bearing. An interesting point is I still have the original bronz drive shaft. A new stainless steel shaft could be the silver bullet but then again silver bullets are hard to find.

--

John & Kathy Impagliazzo
s/v Pooka
Jamestown, RI
1994 C36 TR #1339, M35AC

nbpatterson's picture
nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

[QUOTE=LCBrandt;6958]Thanks for the update. But 6.2 kts in reverse??? At 1500 RPM??? Holy cow! One small slip of the wheel and the prop shaft would have been toast, I suspect. You're a brave soul, mate. Nevertheless, I wish I could see a video of it. May be a hint of future boat design...canards instead of rudders. (Steve Frost, here's the seed of your next April 1 article.)

As for the NVH Project, will you be documenting the sound levels Before and After with a sound meter? Please think about writing this up for JibSheet, as there are many others who are very interested in this project. I, for one. Take lots of photos, please.[/QUOTE]

I am too busy hanging onto the wheel to take a video of the water lapping up the transom step at 6.2 knots in reverse! But let me say that the 6.2 knots was simply a test for this forum and I certainly would not make a habit of it - don't think my nerves could stand it!

However, after all the work I've done on the transmission, the "marbles in the can" is back in forward and partially in neutral. Reverse is nice and quiet (the transmission is probably so loaded up that it has no chance to rattle). So I am thinking it is time to get a new gearbox and stop wasting $$ replacing more bearings, shims, springs and things. I want to get the source of the noise sorted put before sound-proofing the engine room, so sorry about the delay in getting the insulation project done.

Does anyone know where I can a replacement transmission (gearbox) from and how much they cost - I will have to ship it to Sydney? Fortunately, our Australian $ is strong right now.

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
GaryB's picture
GaryB
Last seen: 1 day 8 hours ago
Joined: 10/26/08
Posts: 520

Larry, the orange disc that is in your picture is called a "drivesaver" They offer some flexability to the drivetrain but they are really not a solution to vibration. I thought years ago when I had my 30 Catalina that it would reduce the vibration. Maybe just a little but not very much. What it is though is a break away item should you ever get caught up in something that would torque the whole drivetrain.
According to Hamilton Marine catalog they are made by Globe Marine Products. These folks make an inovative engine mount as well....can't attest to their success though.
I believe that when I purchased the drivesaver it was under $200.
Anyway my two cents worth to your question if it is the orange disc you are referring to.
Gary

--

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: East Boothbay, Maine
Home: Auburn, Maine

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nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

[QUOTE=impag;6975]After having the prop reconditioned, replacing the motor mounts and cutlass bearing, installing the hump hose and having the engine aligned, the vibration still persisted to a lesser degree. At the Newport Boat Show I happened to sit down to lunch with one of the gentlemen who taught the engine seminar at Hansen Marine. The conclusion was that the vibration was due to cavitation of the original 3 bladed prop. The vibration frequently occurs while in a maneuver.[/QUOTE]

John, I have posted quite a bit of detail before in this thread on my efforts to rid my C36 of vibration. The single biggest improvement came after I replaced the original stainless steel prop shaft with a new 316 ss prop shaft, the theory here being that whist the shaft was totally true when measured out of the boat, the soft metal that Catalina originally used was probably prone to whiplash when under load, this being exacerbated when turning (and felt like the rudder bearing was loose!).

My initial efforts included replacing the original 5" engine mounts with Vetus K75 4" mounts (huge difference, but has resulted in misalignment between exhaust manifold and exhaust pot due to engine being pushed back), new flexible couplings between engine and gearbox, and between gearbox and prop shaft, new Volvo through-hull gland with in-built bearing, new cutlass bearing, new Kiwi-prop, replaced all bearings, shims, springs and little things in gearbox with initially good effect (however, noise now returned [url]http://www.c36ia.com/forums/images/smilies/mad.gif[/url]).

All of this made some difference and cost a fortune. Like I said, the biggest difference was replacing the prop shaft itself with a high grade stainless steel shaft and ensuring the overhang behind the cutlass bearing did not exceed the rated 1x shaft diameter, i.e. 1" overhang.

The boat is now all but vibration free. I am just sorting out the returning clatter in the transmission (gearbox) in forward low revs and at idle. Then I will attempt to sound proof the engine bay and hopefully this will rid the boat of the remaining harmonics which I suspect are being set up due to no absorption of the engine noise.

Hope this helps.

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
BudStreet
Last seen: 1 year 4 months ago
Joined: 9/4/09
Posts: 1127

[quote=nbpatterson;7556]I am too busy hanging onto the wheel to take a video of the water lapping up the transom step at 6.2 knots in reverse! But let me say that the 6.2 knots was simply a test for this forum and I certainly would not make a habit of it - don't think my nerves could stand it!

However, after all the work I've done on the transmission, the "marbles in the can" is back in forward and partially in neutral. Reverse is nice and quiet (the transmission is probably so loaded up that it has no chance to rattle). So I am thinking it is time to get a new gearbox and stop wasting $$ replacing more bearings, shims, springs and things. I want to get the source of the noise sorted put before sound-proofing the engine room, so sorry about the delay in getting the insulation project done.

Does anyone know where I can a replacement transmission (gearbox) from and how much they cost - I will have to ship it to Sydney? Fortunately, our Australian $ is strong right now.[/quote]

[URL="http://shop.torresen.com/marine_diesel_direct/?p=details&ident=464539&mf..."]http://shop.torresen.com/marine_diesel_direct/?p=details&ident=464539&mf...

$963.00 for a rebuilt one. Torreson's are well known in the diesel business.

As for new units, their listings only show new ones with 2.04 ratio. I checked ZF's website (they own Hurth now, the HBW100 is now the ZF-10M), seems that ZF no longer makes the 1.79 ratio model, the new ones are either 2.04 or 2.72. You'd have to reprop. New ones cost about $1250US and seem to be widely available in the US.

That rattle in forward seems to be a "feature" of these gearboxes, both of our boats with Hurth trans did that, seems normal as long as it goes away once under some load. It is disconcerting but I've gotten used to it.

Edit: [url]http://www.marinepartsexpress.com[/url] - sells the ZF10M new for $1150 and they seem keen to ship anywhere.

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Gary Teeter
Last seen: 3 years 2 months ago
Joined: 3/10/08
Posts: 49

I replaced my motor mounts with R&D units that I purchased from PYI. I have been happy with them.

PYI recommended two different mounts for my M25xp because the weight of the front of the engine is less than the back. The load on the back mounts is higher because of the flywheel and transmission being on the back, and the location of the mounts being ahead of these heavy items. The front mounts are designed for a lighter load.

--

Gary Teeter
1989 C36 "AnnieG"
Std Rig #966, M25xp
Everett, WA

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nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

[QUOTE=Pat T;7560]Nigel,
If your transmission seems to work as expected except for the rattle I would suspect the damper plate. [/QUOTE]

Hi Pat,

I replaced the worn-out damper plate last year with a polymer coupling which did make a difference. However, there was still a clatter going on. The rattle virtually went away when the mechanic replaced all the gearbox bearing, shims, springs and other little things which i have no idea about, and put a special oil in. Perhaps I am just becoming neurotic over the rattle and should instead get on with sailing!!

Nigel

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
nbpatterson's picture
nbpatterson
Last seen: 7 years 4 weeks ago
Joined: 4/25/09
Posts: 17

[QUOTE=nbpatterson;7596]Hi Pat,

I replaced the worn-out damper plate last year with a polymer coupling which did make a difference. However, there was still a clatter going on. The rattle virtually went away when the mechanic replaced all the gearbox bearing, shims, springs and other little things which i have no idea about, and put a special oil in. Perhaps I am just becoming neurotic over the rattle and should instead get on with sailing!!

Nigel[/QUOTE]

I have just spoke to my mechanic. He said that they put preload onto new bearings when they overhaul gearboxes and that the box is probably just settling in. He too reckons the rattle is normal in these transmissions as the gears are straight-cut. Definitely time to get on with sailing - especially as the weather is stunning here in Sydney at the moment!

Nigel

--
Nigel Patterson
Sydney, Australia
Fresh Aire II, 2001 C36, Hull # 1976
rvfagan
Last seen: 1 month 3 days ago
Joined: 2/15/10
Posts: 4

I was having a very loud knocking noise when below 1000-1100 RPM. Finally discovered the screws holding down the exhaust lift box were loose. Tightened them up and she now sounds wonderful to my ears - finally!!!

--

Ralph Fagan
Terra Nova Yacht Club
Family Time
1995 C36 MK2 #1440

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