Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-01-2013, 01:24   #16
Registered User

Join Date: Oct 2009
Location: australia
Posts: 467
Re: Hard vs Soft Engine Mounts

G' day,
I use have used polyflex mounts & couplings with great success for many years. I suggest you make contact via their website polyflex.com.au/ they have all the answers & recommendations.
__________________

__________________
shakey doug is offline   Reply With Quote
Old 13-01-2013, 03:08   #17
Wayfaring Mariner
 
captain58sailin's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Homer, AK is my home port
Boat: Skookum 53'
Posts: 4,045
Images: 5
Re: Hard vs Soft Engine Mounts

I had an increase in vibration once and thought that one of the motor mounts had failed, upon further investigation found that one of the mounts had loosened and the oil pan was sitting on the bottom of the boat and transmitting the vibration. I did contact Polyflex about new mounts when I thought mine were shot and they were very helpful and responsive.
__________________

__________________
" Wisdom; is your reward for surviving your mistakes"
captain58sailin is offline   Reply With Quote
Old 13-01-2013, 03:57   #18
Bailing as fast as I can.
 
GILow's Avatar

Join Date: Sep 2008
Location: Adelaide, South Australia
Boat: Swanson 42
Posts: 3,585
Re: Hard vs Soft Engine Mounts

Thanks for the recommendation, if I decide to soft mount the engine I will look them up. Calculating the stiffness for the engine mounts is a bit of a complex equation, these sorts of people may be able to help.

Strangely, I can not imagine these guys giving me a convincing case to stay with the hard mounts, given what the sell, so I am still wondering WHY he hard mounted the engine, I feel there has to a good reason.
__________________
GILow is offline   Reply With Quote
Old 13-01-2013, 04:58   #19
Registered User
 
Cherp's Avatar

Join Date: Nov 2008
Location: Hobart Australia
Boat: Catalina Morgan 45
Posts: 308
Re: Hard vs Soft Engine Mounts

I think the hard-mounting thing comes from practice in earlier times. Fishing boats, generally wooden and heavy, often used Gardner engines which were big, heavy and very slow revving. The fishermen hard- mounted them to big heavy beds and it worked fine. They were not too fussed about noise transfer. Then along came the more ,modern high-revving engines and lighter hulls for pleasure boats. Some people just stayed with the old ways as times changed.
__________________
Cherp is offline   Reply With Quote
Old 13-01-2013, 13:19   #20
Bailing as fast as I can.
 
GILow's Avatar

Join Date: Sep 2008
Location: Adelaide, South Australia
Boat: Swanson 42
Posts: 3,585
Re: Hard vs Soft Engine Mounts

Quote:
Originally Posted by Cherp View Post
I think the hard-mounting thing comes from practice in earlier times. Fishing boats, generally wooden and heavy, often used Gardner engines which were big, heavy and very slow revving. The fishermen hard- mounted them to big heavy beds and it worked fine. They were not too fussed about noise transfer. Then along came the more ,modern high-revving engines and lighter hulls for pleasure boats. Some people just stayed with the old ways as times changed.
He he... I think of the Nissan ED 33 as big, heavy and slow revving, but everything is relative! You have a good point and it may be that simple.

The absence of anyone knowing a really compelling reason to stay with the hard mounts it giving me hope, I think it may be safe to convert it to soft mounts when I get the time by the sound of things. Hopefully it is just a case of old fashioned belts and braces thinking and I really would like to see if I can smooth it out a little.

Matt
__________________
GILow is offline   Reply With Quote
Old 13-01-2013, 15:21   #21
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Hard vs Soft Engine Mounts

Quote:
Originally Posted by GILow View Post
The absence of anyone knowing a really compelling reason to stay with the hard mounts it giving me hope, I think it may be safe to convert it to soft mounts when I get the time by the sound of things. Hopefully it is just a case of old fashioned belts and braces thinking and I really would like to see if I can smooth it out a little.

Matt
Maybe to save $$$$$$$$ and labor.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 13-01-2013, 16:27   #22
Bailing as fast as I can.
 
GILow's Avatar

Join Date: Sep 2008
Location: Adelaide, South Australia
Boat: Swanson 42
Posts: 3,585
Re: Hard vs Soft Engine Mounts

Oh you hardened cynic! When have you EVER known a boatie to try and save labour or money...?
__________________
GILow is offline   Reply With Quote
Old 13-01-2013, 19:38   #23
Registered User
 
stillbuilding's Avatar

Join Date: Jan 2008
Location: Hong Kong
Boat: Custom Freya 20m
Posts: 961
Many engines are well balanced and contribute little vibration if hard mounted. Once well set up they can be less trouble.
__________________
stillbuilding is offline   Reply With Quote
Old 13-01-2013, 19:57   #24
Bailing as fast as I can.
 
GILow's Avatar

Join Date: Sep 2008
Location: Adelaide, South Australia
Boat: Swanson 42
Posts: 3,585
Re: Hard vs Soft Engine Mounts

Quote:
Originally Posted by stillbuilding View Post
Many engines are well balanced and contribute little vibration if hard mounted. Once well set up they can be less trouble.
So are you saying it might be a plus for reliability the way it is mounted?

Matt
__________________
GILow is offline   Reply With Quote
Old 13-01-2013, 22:31   #25
Registered User
 
stillbuilding's Avatar

Join Date: Jan 2008
Location: Hong Kong
Boat: Custom Freya 20m
Posts: 961
Many commercial boats are hard mounted for simplicity and robustness. I wonder if a small reason for this might be that the engine is less inclined to be thrown about if a net least line is caught by the prop?
I have owned a couple of boats that came hard mounted and they required very little input over time. I would not change the present arrangement if it works.

If vibration is big issue for some reason then by all means change. Some vibration might be more concerning in a charter yacht where guests want to sleep. I can sleep almost anywhere and maybe even feel more about the boat from the usual working noises. Some are obsessive about eliminating every squeak and tremor.
__________________
stillbuilding is offline   Reply With Quote
Old 16-01-2013, 23:28   #26
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: Hard vs Soft Engine Mounts

my engine is hard mounted, i mentioned it to a very experienced (and old) sailing guru i occasionally get to chat to, all he said was "thats the best way" - theres a bit of vibe but it doesnt bother me much and his comment dismissed the idea i had been considering of converting it to soft mounts (at considerable expense). Its been running since 1978, cant be too bad a design. Your question about why it was done that way - maybe at the time it was built that was considered the best way.
__________________
charliehows is offline   Reply With Quote
Old 16-01-2013, 23:44   #27
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Hard vs Soft Engine Mounts

I think its because you guys are upside down and he didn't want the engine to fall out...

We don't have that problem up here...
__________________
DeepFrz is offline   Reply With Quote
Old 17-01-2013, 00:16   #28
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: Hard vs Soft Engine Mounts

well even if it did up there you'd just pick it up off the ice and put it back...
__________________
charliehows is offline   Reply With Quote
Old 19-01-2013, 03:05   #29
Registered User

Join Date: May 2008
Location: Brisbane, Queensland, Australia
Boat: Swanson 32
Posts: 6
Re: Hard vs Soft Engine Mounts

Howdy, my Swanson 32 built in 1973 has a Volvo MD2B which is also hard mounted. Perhaps the Swanson Brothers just preferred this arrangement: KISS?

Cheers,

Paul
__________________
olympia is offline   Reply With Quote
Old 19-01-2013, 14:57   #30
Registered User

Join Date: Jan 2013
Location: Belgium
Boat: Trintella 1 & 28ft
Posts: 73
Re: Hard vs Soft Engine Mounts

I would stay with hard mounted for reliability if you don't have excessive vibrations. Soft mounts wear and have to be replaced over time.
A proper hard mount is slightly more picky on alignment but can last forever.

My engine is hard mounted (1962) I loosened the shaft coupling and check the alignment when I bought the boat it was correct to 0.001mm after 50 years.

I still haven't seen any soft mounts lasting 50 years.
__________________

__________________
ccgarnaal is offline   Reply With Quote
Reply

Tags
engine

« Bukh 36ME | Dovekie »
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




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:23.


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.