Reply
 
Thread Tools Display Modes
 
Old 06-01-2014, 01:13 PM   #21
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Country: Canada
Vessel Name: Gwaii Haanas
Vessel Model: Vancouver Shipyards Custom Aluminum 52
Join Date: Sep 2013
Posts: 2,451
Props, shafts, struts, cutlass bearings, alignment. Also, Lehmans at idle will shake the boat like a terrier with a rat. Bring them off the power lever stops and they settle down nicely. I had all that on my old GB. I also weather stripped the engine hatch covers, which helped significantly.

Once you are sure all the running gear is straight, an alignment will make a huge difference. It's even recommended every few years as boats are organic and things move. Sorry if I repeated the above.
__________________
Advertisement

__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 06-01-2014, 05:53 PM   #22
Senior Member
 
funangler's Avatar
 
City: Erie PA
Country: USA
Vessel Name: Endless Endeavor
Vessel Model: Custom
Join Date: Dec 2012
Posts: 214
I'm installing a aqua drive myself on a 42ft steel boat with a single perkins 6.354. The drive was over $3000. I should been done by the end of the week I will post if it worth it.
__________________

funangler is offline   Reply With Quote
Old 06-01-2014, 09:54 PM   #23
Guru
 
Capt.Bill11's Avatar
 
City: Sarasota/Ft. Lauderdale
Country: USA
Join Date: Apr 2014
Posts: 5,422
Quote:
Originally Posted by Rduval View Post

Soft mounts + a flex coupliing sounds like a great idea to me, in theory. Are a lot of people using these and is there a reasonably long history of successful use?
I did not install anything as complicated as an Aquadrive system. I used Cushyfloat engine mounts and Federal isolation couplers. The transmission of vibration was greatly reduced at all rpms. And turned the boat into the smoothest running GB with Lehmans I'd ever run. But as they say, YMMV
Capt.Bill11 is offline   Reply With Quote
Old 06-01-2014, 10:11 PM   #24
Senior Member
 
funangler's Avatar
 
City: Erie PA
Country: USA
Vessel Name: Endless Endeavor
Vessel Model: Custom
Join Date: Dec 2012
Posts: 214
PT41 Vibration and Noise Abatement

I installed soft mounts about 6 yrs ago and was very happy. This spring I had to put a different transmission in and the alignment could not be made right. The best fix was an aqua drive.
funangler is offline   Reply With Quote
Old 06-01-2014, 10:17 PM   #25
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by Ski in NC View Post
Alignment problems rarely cause vibrations. If far off, it can break things, but usually unnoticed til then. Aquadrive type drive shafts/bearings also rarely make much of a change.

Under what conditions do you get the noise/vibration? At dead idle in neutral? In gear at idle? At cruise of 1600?

You need to figure out what is causing the issue before proposing a fix.
I agree with much of what you are saying but to me the vibration is less about misalignment than the rigidity of the motor mounts transmitting the vibration to the stringers and on to the rest of the boat. By removing the alignment issue with the Aqua Drive yo can use soft motor mounts that absorb the vibration since alignment is no longer an issue.... Or so the story goes. There does seem to be significant evidence to support the theory and as a machinery designer and manufacturer of many years it seems like sound logic to me.

Of course, I've been wrong before.... (but only once)
Rduval is offline   Reply With Quote
Old 06-01-2014, 10:19 PM   #26
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by funangler View Post
I installed soft mounts about 6 yrs ago and was very happy. This spring I had to put a different transmission in and the alignment could not be made right. The best fix was an aqua drive.
There ya go Funangler! That's what I want to hear.

Do you know what size/model you used and what hp you are running.
Rduval is offline   Reply With Quote
Old 06-01-2014, 10:29 PM   #27
Senior Member
 
funangler's Avatar
 
City: Erie PA
Country: USA
Vessel Name: Endless Endeavor
Vessel Model: Custom
Join Date: Dec 2012
Posts: 214
PT41 Vibration and Noise Abatement

B20 bearing and 75 inch shaft between the transmission and the trust bearing. The motor is 135 hp with a 2:1 transmission. The salesman recommend I move to the next size up because I was at the limit of the lower bearing.
funangler is offline   Reply With Quote
Old 06-02-2014, 12:10 AM   #28
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,890
Quote:
Originally Posted by Rduval View Post
I agree with much of what you are saying but to me the vibration is less about misalignment than the rigidity of the motor mounts transmitting the vibration to the stringers and on to the rest of the boat. By removing the alignment issue with the Aqua Drive yo can use soft motor mounts that absorb the vibration since alignment is no longer an issue.... Or so the story goes. There does seem to be significant evidence to support the theory and as a machinery designer and manufacturer of many years it seems like sound logic to me.

Of course, I've been wrong before.... (but only once)
You can use soft mounts without going to aquadrive shaft line or whatever. The motion of the engine on the soft mounts will not be enough to cause issues with alignment. Most all modern installs use soft mounts and rigid shaft lines. No issues.

The poster who required the aquadrive did so by replacing a tranny with different dimensions, not because of going to soft mounts. (at least that is how I understood his post)
Ski in NC is offline   Reply With Quote
Old 06-02-2014, 12:13 AM   #29
Senior Member
 
funangler's Avatar
 
City: Erie PA
Country: USA
Vessel Name: Endless Endeavor
Vessel Model: Custom
Join Date: Dec 2012
Posts: 214
Quote:
Originally Posted by Ski in NC View Post
You can use soft mounts without going to aquadrive shaft line or whatever. The motion of the engine on the soft mounts will not be enough to cause issues with alignment. Most all modern installs use soft mounts and rigid shaft lines. No issues.

The poster who required the aquadrive did so by replacing a tranny with different dimensions, not because of going to soft mounts. (at least that is how I understood his post)

Correct I really did not want to spend the money! The R+D mounts did a great job.
funangler is offline   Reply With Quote
Old 06-02-2014, 06:45 AM   #30
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,928
Just went back to the original post....

Rduval, is this the first big boat you have owned and have spent some time operating from inside a cabin?

Not to be insulting and the boat could certainly be an issue...but you are sounding like you know more and trust more from magazines (got plenty of boating friends that sound the same) than from many of us with thousands of actual cruising miles.

many of our boats are loud and may feel less than perfect at higher Lehman RPMs (say 1900 and above)...many cruise at 1600-1800 or so and say the noise and motion are pleasant but certainly far from gone.

If you are deadest on an aqua drive...go for it...not nearly as many out there for a reason...they do what they say they do but for most just not worth the complication and expense because a properly tuned, properly aligned engine and drive train, and reasonably well done sound proofed engine room is not bad at all....
psneeld is offline   Reply With Quote
Old 06-02-2014, 07:11 AM   #31
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by Ski in NC View Post
You can use soft mounts without going to aquadrive shaft line or whatever. The motion of the engine on the soft mounts will not be enough to cause issues with alignment. Most all modern installs use soft mounts and rigid shaft lines. No issues.

The poster who required the aquadrive did so by replacing a tranny with different dimensions, not because of going to soft mounts. (at least that is how I understood his post)
I'm a little confused now (a lot actually), I was told by a number of people including Brian Smith at American Diesel that the mounts have to be hard or the misalignment caused under torque load will wear your cutlass bearing, stuffing box and output bearing on the end of the gear reduction unit.

If modern designs are using soft mounts how do they differ from the older designs such that alignment is no longer a problem.
Rduval is offline   Reply With Quote
Old 06-02-2014, 07:50 AM   #32
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by psneeld View Post
Just went back to the original post....

Rduval, is this the first big boat you have owned and have spent some time operating from inside a cabin?

Not to be insulting and the boat could certainly be an issue...but you are sounding like you know more and trust more from magazines (got plenty of boating friends that sound the same) than from many of us with thousands of actual cruising miles.

many of our boats are loud and may feel less than perfect at higher Lehman RPMs (say 1900 and above)...many cruise at 1600-1800 or so and say the noise and motion are pleasant but certainly far from gone.

If you are deadest on an aqua drive...go for it...not nearly as many out there for a reason...they do what they say they do but for most just not worth the complication and expense because a properly tuned, properly aligned engine and drive train, and reasonably well done sound proofed engine room is not bad at all....
No insult taken.

I have had many vessels both sail and power, big and small. But this is our first diesel trawler, and our first of any kind where the lower helm and salon are, literally, right on top of the engines.

If the vibration was only at idle and possibly one or two specific rpm, we could easily live with that. Problem is, there are only one or two rpm's that it isn't intolerable.

Sound proofing can only do so much in our case for 2 reasons;

1) the salon floor is 3" thick and already insulated and the coolant tank already sits in a hole with 1" clearance and I'm quite sure removing the rocker covers to adjust the valves or service the injectors will require uncoupling the shafts and dropping the engines off the front mounts. (That or removing the Galley!)

2) Perhaps worst of all is that most of the noise comes from sympathetic vibration of the bulkheads, the fridge, the stove, cabin doors, etc.

So it's not so much about sound reduction from the engines as isolating the vessel from the engines to prevent the sympathetic vibration.

That's why I'm leaning towards soft mounts and, form what I've gathered so far, soft mounts seem to require a flex joint of some sort.

So that's where I sit. Clearly unclear and undecided about the best course of action.
Rduval is offline   Reply With Quote
Old 06-02-2014, 07:55 AM   #33
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by funangler View Post
I'm installing a aqua drive myself on a 42ft steel boat with a single perkins 6.354. The drive was over $3000. I should been done by the end of the week I will post if it worth it.
I look forward to hearing that....
Rduval is offline   Reply With Quote
Old 06-02-2014, 08:19 AM   #34
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,928
I think because so many have boats without aquadrive type setups....you have to make a big decision...one I also went through.

When you are in the fork in the road between multiple fixes. One is chasing down one or multiple fixes that may or may not ever solve your problem. Frustrating when it's the last thing or it never comes. But very satisfying when the first or second tweak fixes things good enough and you haven't spent much at all. This fork is best when you are doing the work yourself (most of it's easy if you are handy).

The other fork is where you run out and buy an aquadrive and start the process of redoing everything in a simple and orderly way. Chances are everything will be good at the end ....but like many of us said...not necessarily better with an aquadrive than plain old normal setup.

The only real difference is money and a gamble. No one can give advice good enough to really set your course because it's gambling your money and time.

I'm sure you have made plenty of similar decisions in your life...use your method for deducting the best answer for you.

Good luck!!!!
psneeld is offline   Reply With Quote
Old 06-02-2014, 10:46 AM   #35
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,724
Rduval,
You may want to evaluate your boat more closely.

First go for a ride in a similar boat and compare vibration.

Secondly take a good look at your boat to see if there's something different about your boat. Especially something like an unusual modification. Anything that is not original may cause vibration especially if it is resonate to the same frequencies as the engine vibration. Engines vibrate. That's a given but the annoying vibration can come from something that is being excited by the engine shaking. Imagine a bulkhead is attached to the engine stringers/beds. The bulkhead may not vibrate (or drum) much at all until the engine gets to a certain frequency (rpm) that the bulkhead is resonate to. Like a tuning fork. And then the bulkhead shakes the boat so the shaking and noise is much greater than what the engine could create by itself.

If you bolted a Lehman to an extremely large concrete slab w no enclosure you would be saying "what vibration?". In that case the engine can't transmit much vibration to you because it can't shake mega tons of concrete so you don't feel any vibration. You don't hear much either because there's no enclosure to contain and resonate the vibration of the air near the engine.

Your engine itself isn't causing your vib problem. It's what's attached to the engine that's causing the problem. If you have vibration on your boat that was not present when the boat was new and the level of vibration then was nice and low something has changed. The boat probably was fairly smooth when new so if you can discover that change or alteration your problem could be solved. And solved w/o the trouble and expense of an Aqua Drive.

Sometimes a good marine mechanic can spot unusual things that would cause excessive vibration almost immediately. They would be more likely to uncover a problem than most of us so a few bucks spent thus may be well spent. Try and find a guy that's spent 40 or so years in boat bilges as he knows what's normal and what's not.

Anyone that can EASILY afford an AD should consider installing one but most of us would find it expensive.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 06-02-2014, 11:31 AM   #36
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,890
Quote:
Originally Posted by Rduval View Post
I'm a little confused now (a lot actually), I was told by a number of people including Brian Smith at American Diesel that the mounts have to be hard or the misalignment caused under torque load will wear your cutlass bearing, stuffing box and output bearing on the end of the gear reduction unit.

If modern designs are using soft mounts how do they differ from the older designs such that alignment is no longer a problem.
Hard mounts are not necessary to keep the shaft line happy. They do have a point that if motor moves around, alignment will change. But it just does not change enough. A flex mount might displace 1/8", and engine lifts one side, lowers the other, so shaft does not move that much.

Order a brand new Cummins engine, it comes with soft mounts. Buy a brand new boat, they come with soft mounts.

At idle, the vibes transmitted into the boat are very harsh with hard mounts. That will be fixed with soft mounts. Above idle and at cruise, the mounts make little difference. At higher revs the engine produces very little vibration. At idle, it produces a lot.

So if you have idle shake, fix that with soft mounts. More analysis needed to figure out the other noise/vibe issue.

And slap that idiot that built a galley over your rocker cover. Hate seeing stupid things like that.
Ski in NC is offline   Reply With Quote
Old 06-02-2014, 11:40 AM   #37
Veteran Member
 
Rduval's Avatar
 
City: WYC, Port Whitby, Ontario
Country: Canada
Vessel Name: Bonaventure
Vessel Model: Cheer Men PT41 Europa
Join Date: May 2014
Posts: 93
Quote:
Originally Posted by Ski in NC View Post
And slap that idiot that built a galley over your rocker
cover. Hate seeing stupid things like that.
Boggles the mind really. It looks like the design was for a single and somebody wanted twins so they just put twins in there and didn't change anything else.

Thanks for the other advise too.
Rduval is offline   Reply With Quote
Old 06-02-2014, 05:53 PM   #38
Guru
 
Shoalwaters's Avatar
 
City: Rodney Bay Lagoon
Country: St. Lucia, West Indies
Vessel Name: "Dragon Lady"
Vessel Model: DeFever 41
Join Date: Feb 2008
Posts: 681
This post has nothing to do with vibration, but everything to do with noise.

Access to my engine room is via 3 panels along the centerline of the saloon plus two long panels, one ether side. Originally lift-out, I decided to fit the centerline pannels with hinges as in the pic below. The panels (like the rest of the engineroom overhead) were faced with that familiar "fiber-board with holes". It had become greasy and generally ragged, so I decided to remove it. Underneath was a 3" thick layer of styrofoam! OK for heat insualtion, but next to useless for sound deadening. Further investigation revealed that the long removable pannels were also insulated with styrofoam and the fixed part of the engineroom "ceiling" had nothing save fiberboard and an air-space. I replaced the whole lot with a sound-deadening material sold by our local chandlery. With both engines and the generator running, the reduction in noise level is remarkable. Other forum members with mid-80's Taiwanese boats might find it worth while exploring what their "4-inch thick saloon floors" are really made of.
Attached Thumbnails
Click image for larger version

Name:	Hatch-2.jpg
Views:	70
Size:	105.2 KB
ID:	30302  
__________________
Mike
If all else fails, read the instructions
If it ain't broke, don't fix it
Shoalwaters is offline   Reply With Quote
Old 06-02-2014, 06:19 PM   #39
Guru
 
rochepoint's Avatar
 
City: Sidney BC
Country: Canada
Vessel Name: Rochepoint
Vessel Model: 1985 Cheer Men PT38 Sedan
Join Date: Apr 2009
Posts: 1,192
Rick
If your Pt is the same as ours there is a third lift-out hatch in the galley that is underneath the counter and part of the seat but you have to unbolt the counter and seat (easy to do) and move it out of the way.
Attached Files
File Type: pdf PT Hatch.pdf (51.9 KB, 47 views)
__________________
Cheers Mike Barge
MV Rochepoint
Sidney, British Columbia.
"Yes, I have the right anchor"
rochepoint is offline   Reply With Quote
Old 06-02-2014, 08:15 PM   #40
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 5,750
Quote:
Originally Posted by Shoalwaters View Post
This post has nothing to do with vibration, but everything to do with noise...The panels (like the rest of the engineroom overhead) were faced with that familiar "fiber-board with holes". It had become greasy and generally ragged, so I decided to remove it. Underneath was a 3" thick layer of styrofoam! .... Other forum members with mid-80's Taiwanese boats might find it worth while exploring what their "4-inch thick saloon floors" are really made of.
Mike: Good post. You described Hobo's engine room. How long did the project take and were there any Oh shits along the way?
Attached Thumbnails
Click image for larger version

Name:	Hobo Complete 113.jpg
Views:	62
Size:	171.0 KB
ID:	30315  
__________________

Larry M is offline   Reply With Quote
Reply

Tags
lehman, motor mounts, noise, vibration

Thread Tools
Display Modes

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





All times are GMT -5. The time now is 04:11 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012