Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-05-2016, 10:16   #1
Registered User

Join Date: Aug 2015
Location: Port Townsend, WA
Boat: Tashiba-31
Posts: 216
Images: 1
Blue & White Snow

I'm new to boat ownership and just learning my way. The site survey for my boat shows a number of values that are covered in corrosion (blue & white snow). What causes this, how do I deal with it and is there anyway to prevent it from happening?
__________________

__________________
dmksails is offline   Reply With Quote
Old 11-05-2016, 15:22   #2
Moderator
 
JPA Cate's Avatar

Join Date: Nov 2011
Location: aboard, cruising in Australia
Boat: Sayer 46' Solent rig sloop
Posts: 10,655
Re: Blue & White Snow

A pic would help.

I have seen aluminum corrode, leaving a sticky, white globby mess. If that is what we're talking about here, the extent to which it can be fixed varies with its location. You have to clean it, and then fix it so salt water can't get at it. If it is structural, it is a big deal.

Ann
__________________

__________________
Ann, with Jim, aboard US s/v Insatiable II, in Oz, very long term cruisers
JPA Cate is offline   Reply With Quote
Old 11-05-2016, 15:41   #3
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: UK/Portugal
Posts: 20,188
Images: 2
Send a message via Skype™ to boatman61
pirate Re: Blue & White Snow

Electrolysis is usually the cause with aluminium.... white or yellowish.. the blue I don't know.
__________________


Born To Be Wild
boatman61 is offline   Reply With Quote
Old 11-05-2016, 16:07   #4
Registered User

Join Date: Jan 2016
Posts: 429
Re: Blue & White Snow

Corrosion products on metals - you mean valves I guess - can be different colours depending on the cause.

Never have known exact causes of the colours I've seen.

White and bluish-green I associate with stray electrical current in wet areas.
Pink & green is often found on skin fittings, ball valves etc. - anything brass.

Battery spills, chemical spills, toilet effluent, who knows?
__________________
unclemack is offline   Reply With Quote
Old 11-05-2016, 17:17   #5
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,592
Re: Blue & White Snow

Poultice corrosion, crevice corrosion, galvanic corrosion, stray current corrosion, electrochemical corrosion, dealloying, dezincification, graphitic corrosion and many more, take your pick.

We need more info and photos,. What are the metals and what components are involved ? Fresh water ? Salt water ? Boat bonded ?
Anode type ? Hull material ? Shore power ?

Colour of corrosion byproducts has nothing to do with the cause and neither does electrolysis.

PS. I'm a Certified Corrosion Analyst.
__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 12-05-2016, 09:36   #6
Registered User

Join Date: Aug 2015
Location: Port Townsend, WA
Boat: Tashiba-31
Posts: 216
Images: 1
Re: Blue & White Snow

I've uploaded a photo of one of the valves into the photo section. Not sure how to add it to this thread - I get a black x instead of a photo

Blue Snow - Corroded valuve Cruisers & Sailing Photo Gallery

__________________
dmksails is offline   Reply With Quote
Old 12-05-2016, 10:03   #7
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,334
Re: Blue & White Snow

That's seawater or head fluid corrosion. Looks like a check valve that is leaking, may not be a valve you even want in there. The green/blue is not uncommon on bronze.
The little I can see of the seacock looks pretty nice. maybe that's a sink drain with a flapper valve to avoid sea water getting in the sink when heeled over...?
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 12-05-2016, 10:18   #8
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Blue & White Snow

Quote:
Originally Posted by Cheechako View Post
That's seawater or head fluid corrosion. Looks like a check valve that is leaking, may not be a valve you even want in there. The green/blue is not uncommon on bronze.
The little I can see of the seacock looks pretty nice. maybe that's a sink drain with a flapper valve to avoid sea water getting in the sink when heeled over...?
Yep-common verdigris from leaking swing check valve- basically harmless-but indicates a slow leak. https://en.wikipedia.org/wiki/Verdigris
It would cause failure in time.
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 12-05-2016, 10:21   #9
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,334
Re: Blue & White Snow

Yes, if it's below the water line I would definitely replace that swing valve... it could very well be a hardware store item which may be more brass than bronze.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 12-05-2016, 11:34   #10
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,022
Re: Blue & White Snow

That kind of corrosion means "throw out whatever is under this". And it takes a long time to build up to that amount, which warns you that boat has been receiving little if any of the normal maintenance over a long time. "Danger Will Robinson!"


A competent surveyor would arguably have said "indicates MUST BE REPLACED" and if they didn't...you have to look over the rest of the survey extra carefully as well.


The good news is that the corroded stuff should all be able to be unscrewed, and the thru-hull seems unaffected by it.
__________________
hellosailor is offline   Reply With Quote
Old 12-05-2016, 12:29   #11
Registered User

Join Date: Aug 2015
Location: Port Townsend, WA
Boat: Tashiba-31
Posts: 216
Images: 1
Re: Blue & White Snow

Thanks for the info! Yes the surveyor did flag this item as needed to be replaced. Unfortunately, I wasn't there when the survey was done and could not ask him about it. Definitely going to replace, but wanted to know if it was an indication of a larger problem.
__________________
dmksails is offline   Reply With Quote
Old 12-05-2016, 18:04   #12
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Blue & White Snow

Quote:
Originally Posted by dmksails View Post
Thanks for the info! Yes the surveyor did flag this item as needed to be replaced. Unfortunately, I wasn't there when the survey was done and could not ask him about it. Definitely going to replace, but wanted to know if it was an indication of a larger problem.

Suggest you determine why the swing check valve was installed in first place.
Check valves are known to be troublesome. They are prone to sticking,either open or closed or part way,either due to corrosion,dirt,etc. They can also trap water which is a freeze problem in cold climate haul out.

Cheers/ Len
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 13-05-2016, 13:36   #13
Registered User

Join Date: Aug 2015
Location: Port Townsend, WA
Boat: Tashiba-31
Posts: 216
Images: 1
Re: Blue & White Snow

Not sure why the check value was installed. What would be the correct configuration?
__________________
dmksails is offline   Reply With Quote
Old 13-05-2016, 13:59   #14
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,334
Re: Blue & White Snow

Quote:
Originally Posted by dmksails View Post
Not sure why the check value was installed. What would be the correct configuration?
Would need to know what the hose is for!
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 13-05-2016, 14:21   #15
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Blue & White Snow

Quote:
Originally Posted by dmksails View Post
Not sure why the check value was installed. What would be the correct configuration?
Hi
Here is a link to a variety of useful boat info from Maine Sail-for future ref.
www.marinehowto.com

I don't know which device your check valve is plumbed to,but I will guess it to be for the bilge pump. When a bilge pump stops pumping,there is still water in the hose that can flow backwards thru the stopped pump & end up back in the bilge. This is harmless,but annoying to some people. A properly placed check(one way) valve will stop most of this water from back flowing. But it can be troublesome for reasons given in previous posts. A further consideration is that the next time the BP operates,it has to pump enough pressure to open the flapper in the check valve,which is held closed by the weight of the previously blocked water. This puts extra start up stress on pump,which may cause premature burnout due to higher current needed. I'm not saying "don't do it",but from my,& other's,experiences,avoid if possible.
A less troublesome way is to put a "hump" in the hose as it leaves BP so that water runs downhill from the hump to thru hull.
I can't tell from your pic,but another situation that check valves are sometimes used in,is when one thru hull outlet is used by more than one device. eg: two bilge pumps fed to a tee at the thru hull. One pump runs & forces water back thru the other pump. This tee arrangement is to avoid installing another thru hull & seacock. Some folks like to limit the number of thru hull fittings.

Hope this helps a bit. If you post a bigger pic & tell us what is plumbed to that seacock,you will get other suggestions.

Cheers/ Len
__________________

__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
How white is too white? Ryban General Sailing Forum 54 21-06-2015 16:36
boat launch & snow sailorboy1 Our Community 21 06-04-2013 08:06
Snow Birds Heading South Rickwig Atlantic & the Caribbean 2 02-11-2009 09:50
Snow!!!! What do I need to check? denmanislander Construction, Maintenance & Refit 10 07-01-2009 17:26



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 21:58.


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.