Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-09-2013, 14:00   #46
Registered User

Join Date: Oct 2012
Location: Currently Tasmania after Pacific crossing
Boat: Catalina 42
Posts: 217
Re: Keel Damage

On a cold dark night, far out to sea in 30 knots of wind, an issue like that keel...even patched would keep my mind and stomach churning!

Someone mentioned x-ray... that would seem the best cost effective least intrusive suggestion to see exactly whats going on inside that cast iron keel.

Thankyou for my lead keel Catalina!
__________________

__________________
Amnesia II is offline   Reply With Quote
Old 07-09-2013, 14:00   #47
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,592
Re: Keel Damage

Quote:
Originally Posted by Jim Cate View Post
G'Day BP,

In order for the differential in coefficients of expansion to cause the cracking there would have to be some significant changes in temperature. When the keel and lower hull are immersed in water which remains at a fairly constant temperature, I can't believe in this being the cause of cracking.
Being in Canada cold temperatures are a bit of an issue particularly when boats are stored over the winter on the hard. Swimming in the deeper Great Lakes it is quite common to haver warm water around your upper body while your toes are turning blue. Alos when sailing from shallow water to deeper water where thera can easily be a 15 degree difference, the FRP and lead will change at distinctly different rates.
__________________

__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 07-09-2013, 14:03   #48
Registered User
 
neilpride's Avatar

Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 3,099
Re: Keel Damage

Cracks are fairly common in bolted keels at the joint area, C&c are famous for keel smile, nothing can stop a small crack at the fairing , the keel work hard and flex at some extent, but most cracks are just cosmetic, and someone sugested glass the area to avoid see the crack next time, but be aware, because i see people doing that in serious cracks and big gaps making the isue worst, probably checking the torque at the keel bolts and the joint for leaks is the procedure, and a small crack is not a big deal.....serious gaps and long cracks are another history...
__________________
neilpride is offline   Reply With Quote
Old 07-09-2013, 14:09   #49
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,514
Images: 14
Re: Keel Damage

Quote:
Originally Posted by boatpoker View Post
Being in Canada cold temperatures are a bit of an issue particularly when boats are stored over the winter on the hard. Swimming in the deeper Great Lakes it is quite common to haver warm water around your upper body while your toes are turning blue. Alos when sailing from shallow water to deeper water where thera can easily be a 15 degree difference, the FRP and lead will change at distinctly different rates.
Are you suggesting the photos show a failed joint between the GRP hull and the cast iron keel? because I beg to differ. From what I can see in this photo, I think this is a multiple cracks in the cast iron from possibly having hit something big and hard.

Would I buy the boat, sure but less the cost of fitting a new keel.


http://www.cruisersforum.com/forums/...7&d=1375549451
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 07-09-2013, 14:51   #50
Armchair Bucketeer
 
David_Old_Jersey's Avatar

Join Date: Oct 2006
Posts: 10,013
Images: 4
Re: Keel Damage

Quote:
Originally Posted by boatpoker View Post
PS. Here is a list of sailboats I have surveyed. Perhaps this will give you an indication of how I came to my conclusions.
I don't dispute your experience - but my point still stands for OP......even if "Normal" does not mean you have to (or should) buy that deficiency.

BTW I call it a deficiency because if it was not then would be highlighted in the sales brochure as a plus point: "after a few years the keel will start to detach - to aid performance" .
David_Old_Jersey is offline   Reply With Quote
Old 07-09-2013, 15:20   #51
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,514
Images: 14
Re: Keel Damage

Quote:
Originally Posted by neilpride View Post
Cracks are fairly common in bolted keels at the joint area,
Not true, the sentence should read "cracks are sometimes seen between a bolted keel and the hull at the joint area", but not in the cast iron keel.

Quote:
Originally Posted by neilpride View Post
C&c are famous for keel smile, nothing can stop a small crack at the fairing
Okay

Quote:
Originally Posted by neilpride View Post
the keel work hard and flex at some extent, but most cracks are just cosmetic,
What? how does a piece of cast iron several inches thick flex? cast iron doesn't work harden.
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 07-09-2013, 15:55   #52
Registered User
 
neilpride's Avatar

Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 3,099
Re: Keel Damage

Quote:
Originally Posted by Pete7 View Post
Not true, the sentence should read "cracks are sometimes seen between a bolted keel and the hull at the joint area", but not in the cast iron keel.

Okay



What? how does a piece of cast iron several inches thick flex? cast iron doesn't work harden.

Look, maybe you dont get the point or i dont explain very well, cracks are fairly common in fin keels with bolts, no matter if is lead or iron, and the cracks appear at the fwd or aft trailing edges where the metal joint the hull, FG stub or simple bolted keel flat to the hull like some builders do, and in most cases is cosmetic when fillers are used to hide the joint , fillers or primers and antifouling together, and yes belive or not Keels work when the boat heel or if is pounding in a seaway, iron or lead, the fairing actually just need a minimal inflexion to crack, or could be a mix between hull and keel , the keel is rigid , yes , the hull not, so just figurate,, cracks are notorious when the boats get older , haulouts, groundings, just the simple fact of sailing, etc. but yes if you prefer the term of flexing joint im ok with that to , Cheers...
__________________
neilpride is offline   Reply With Quote
Old 07-09-2013, 16:24   #53
Registered User

Join Date: Oct 2012
Location: Currently Tasmania after Pacific crossing
Boat: Catalina 42
Posts: 217
Re: Keel Damage

Quote:
Originally Posted by neilpride View Post
Look, maybe you dont get the point or i dont explain very well, cracks are fairly common in fin keels with bolts, no matter if is lead or iron, and the cracks appear at the fwd or aft trailing edges where the metal joint the hull, FG stub or simple bolted keel flat to the hull like some builders do, and in most cases is cosmetic when fillers are used to hide the joint , fillers or primers and antifouling together, and yes belive or not Keels work when the boat heel or if is pounding in a seaway, iron or lead, the fairing actually just need a minimal inflexion to crack, or could be a mix between hull and keel , the keel is rigid , yes , the hull not, so just figurate,, cracks are notorious when the boats get older , haulouts, groundings, just the simple fact of sailing, etc. but yes if you prefer the term of flexing joint im ok with that to , Cheers...

Neil, I think you may be missing the point a little here....If you care to look again at the OP's photo of the damaged keel, the crack appears to be NOT in a straight line as per a keel/stub connection crack would appear.
This crack zigzags in many directions and clearly looks to me to be a fault within the metal keel....and not a joint movement crack!

Just my retired metalworker observation!
__________________
Amnesia II is offline   Reply With Quote
Old 07-09-2013, 16:41   #54
Registered User
 
Mike OReilly's Avatar

Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 4,022
Quote:
Originally Posted by boatpoker View Post

Being in Canada cold temperatures are a bit of an issue particularly when boats are stored over the winter on the hard. Swimming in the deeper Great Lakes it is quite common to haver warm water around your upper body while your toes are turning blue. Alos when sailing from shallow water to deeper water where thera can easily be a 15 degree difference, the FRP and lead will change at distinctly different rates.
I'm no where near an expert, but I can confirm that hairline cracks are common on boats with bolted keels that I see up here on Lake Superior. I've always assumed it was due to the slight flexing, but perhaps temperature also plays a role. In any case, it's definitely not uncommon, and in my limited experience (and the expansive experience of my fellow sailors up here) almost always cosmetic.
__________________
Why go fast, when you can go slow.
BLOG: www.helplink.com/CLAFC
Mike OReilly is online now   Reply With Quote
Old 07-09-2013, 16:45   #55
Registered User
 
Mike OReilly's Avatar

Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 4,022
Quote:
Originally Posted by Amnesia II View Post

Neil, I think you may be missing the point a little here....If you care to look again at the OP's photo of the damaged keel, the crack appears to be NOT in a straight line as per a keel/stub connection crack would appear.
I also agree, the pics are not cosmetic hairline fractures. These are not examples of keel bolt flexing. These look to be substantive damage. Impact? Rusting iron keel?
__________________
Why go fast, when you can go slow.
BLOG: www.helplink.com/CLAFC
Mike OReilly is online now   Reply With Quote
Old 07-09-2013, 17:20   #56
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,439
Re: Keel Damage

Quote:
Originally Posted by boatpoker View Post
Being in Canada cold temperatures are a bit of an issue particularly when boats are stored over the winter on the hard. Swimming in the deeper Great Lakes it is quite common to haver warm water around your upper body while your toes are turning blue. Alos when sailing from shallow water to deeper water where thera can easily be a 15 degree difference, the FRP and lead will change at distinctly different rates.
Well, BP, lets look at the numbers: For a typical fin keel

As stated above, the respective coefficients for GRP and Pb are 15.1 and 14
times 10 to the minus 6 inches per inch per degree F. Thus for your 15 degree temperature differential, we get (15.1-14) *10^-6 * 15 per inch of keel root length. For, say, a keel with a 6 foot root, this works out to
1.1*10^-6*15*72= 1188*10^-6 inches = a bit over one one-thousandth of an inch. I doubt if that differential would cause cracking. Even if you throw in storage on the hard in winter, with temperatures one hundred degrees below the summer norm we only get about 7 thousandth of an inch, spread out over the 72 inch length. I'm not competent to really judge whether that is too much, but my seat of the pants guess is that is not.

For boats in more reasonable climates where they stay in the water full time the temperature range, of course, is far less, yet we see this sort of keel root cracking from time to time. It seems to me that we must look for a different cause.

BTW, the coefficients quoted are from Coefficients of Linear Thermal Expansion
should you wish to check on them.

Cheers,

Jim
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is online now   Reply With Quote
Old 07-09-2013, 23:17   #57
Registered User
 
neilpride's Avatar

Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 3,099
Re: Keel Damage

Quote:
Originally Posted by Amnesia II View Post
Neil, I think you may be missing the point a little here....If you care to look again at the OP's photo of the damaged keel, the crack appears to be NOT in a straight line as per a keel/stub connection crack would appear.
This crack zigzags in many directions and clearly looks to me to be a fault within the metal keel....and not a joint movement crack!

Just my retired metalworker observation!
Yes i know , im just trying to explain why sometimes we get that tiny cracks at the joint , nothing related to the OP pictures, the Op keel in my opinion need a sandblasting and see if there is still clean metal somewhere.. we do a similar job here with a bene 50 last year , iron keel complety rusted, sandblasting, we found a lot of piting and deep damaged, primed, epoxy fairing, more primer, and done... even we sandblast the torpedo bulb at the bottom with the boat lifted with the crane. Cheers..
__________________

__________________
neilpride is offline   Reply With Quote
Reply

Tags
paracelle

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 21:05.


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.