seawater system - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Diesel
 Not a Member? 


Like Tree1Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 03-10-2014
Member
 
Join Date: Jun 2013
Posts: 46
Thanks: 9
Thanked 0 Times in 0 Posts
Rep Power: 0
carlager is on a distinguished road
seawater system

The seawater strainer placed above sealevel and on the highest point on the seawater system on our Yanmar 3gm30f is empty when the engine is not running.

Is this normal ?
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 03-10-2014
Group9's Avatar
Senior Member
 
Join Date: Oct 2010
Posts: 1,648
Thanks: 20
Thanked 60 Times in 59 Posts
Rep Power: 5
Group9 is on a distinguished road
Re: seawater system

I don't know. Mine is below sea level and stays full of water all of the time.
__________________
On the northern Gulf of Mexico.


"Best thing to do is get her out on the ocean. If anything's gonna happen, it's gonna happen out there." Captain Ron Rico
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 03-10-2014
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 15,303
Thanks: 88
Thanked 241 Times in 232 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: seawater system

Quote:
Originally Posted by carlager View Post
The seawater strainer placed above sealevel and on the highest point on the seawater system on our Yanmar 3gm30f is empty when the engine is not running.

Is this normal ?
Doesn't sound 'normal' to me.. it also means your impeller must run dry on every startup for a moment.. Is there room to relocate it? Ours is also below waterline and always 'primed'.
jrd22 likes this.
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 03-10-2014
Member
 
Join Date: Jun 2013
Posts: 46
Thanks: 9
Thanked 0 Times in 0 Posts
Rep Power: 0
carlager is on a distinguished road
seawater system

The impeller is on the other side of the strainer and does not run empty
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 03-10-2014
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 15,303
Thanks: 88
Thanked 241 Times in 232 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: seawater system

Are you saying the strainer is after the impeller? If the impeller is (properly) downstream of the strainer then it's pulling air for a bit until the system is once again flooded...
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 03-10-2014
boatpoker's Avatar
Senior Member
 
Join Date: Jul 2008
Location: Toronto
Posts: 1,083
Thanks: 8
Thanked 25 Times in 24 Posts
Rep Power: 7
boatpoker is on a distinguished road
Re: seawater system

Quote:
Originally Posted by Faster View Post
Are you saying the strainer is after the impeller? If the impeller is (properly) downstream of the strainer then it's pulling air for a bit until the system is once again flooded...
Faster is absolutely correct the impeller will run dry for a short period. Even if it is downhill from the strainer to the pump and that section of hose is full of water, the air in the empty strainer will get sucked through the impeller.
That impeller is going to have a very short life and failure will be sudden. When an impeller fails you have a few minutes at most to notice the overheat and shut her down or serious damage will occur.
__________________
Dirt People Scare me
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 03-11-2014
Member
 
Join Date: Jun 2013
Posts: 46
Thanks: 9
Thanked 0 Times in 0 Posts
Rep Power: 0
carlager is on a distinguished road
seawater system

You are right. The strainer should be full when the engine is not running. Greased the O-ring on the lid to the strainer. Now there is vacuum when the engine is not running and water In in strainer
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 03-11-2014
boatpoker's Avatar
Senior Member
 
Join Date: Jul 2008
Location: Toronto
Posts: 1,083
Thanks: 8
Thanked 25 Times in 24 Posts
Rep Power: 7
boatpoker is on a distinguished road
Re: seawater system

Quote:
Originally Posted by carlager View Post
You are right. The strainer should be full when the engine is not running. Greased the O-ring on the lid to the strainer. Now there is vacuum when the engine is not running and water In in strainer
Glad you got it worked out. I'd recommend you pull that impeller for a close inspection and if possible reposition the strainer as low as you can get it, preferably below waterline (difficult in many sailboats).
__________________
Dirt People Scare me
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 03-12-2014
Senior Member
 
Join Date: Feb 2010
Location: Narragansett Bay
Posts: 9,444
Thanks: 10
Thanked 155 Times in 141 Posts
Rep Power: 6
Minnewaska will become famous soon enough Minnewaska will become famous soon enough
Re: seawater system

Could be an air leak at the strainer itself, or one of the hose connections. Clear seawater lines are great for detecting air leaks. You can see the bubble constantly flowing through.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Jeanneau 54DS

In the harsh marine environment, something is always in need of repair. Margaritas fix everything.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 03-13-2014
Samuelmonosov's Avatar
Member
 
Join Date: Mar 2014
Location: Santa Barbara
Posts: 36
Thanks: 2
Thanked 0 Times in 0 Posts
Rep Power: 0
Samuelmonosov is on a distinguished road
Re: seawater system

I agree with minnewaska there must be a loose fitting or opening somewhere in the line that is allowing for the vacuum in the line. Does it immediately empty, or does it take its time? Does that water run back to the engine or through the exhaust line? Speaking of which, you may want to check the exhaust line and make sure that it doesn't exit below the strainer. That would create the vacuum issue you are experiencing.


Sent from my iPad using Tapatalk
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
slow drip, seawater pump ereiss Diesel 12 07-25-2012 09:23 PM
Engine seawater pump rebuild OceanNavigator Ocean Navigator 1 07-03-2012 03:04 PM
Battery Desalinates Seawater deow General Discussion (sailing related) 0 02-11-2012 02:27 PM
Using Seawater to cool Cabin DallasAB Gear & Maintenance 11 06-04-2007 11:55 PM
Freshwater to seawater ratio wanabe Cruising & Liveaboard Forum 30 04-24-2007 10:57 PM


All times are GMT -4. The time now is 12:10 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.