Encapsulated Keel? - SailNet Community
 6Likes
Reply
 
LinkBack Thread Tools
post #1 of 42 Old 04-27-2013 Thread Starter
Senior Member
 
L124C's Avatar
 
Join Date: Oct 2007
Posts: 1,400
Thanks: 51
Thanked 3 Times in 3 Posts
Rep Power: 8
 
Encapsulated Keel?

Saw this Ericson in the yard the other day. I'm under the impression Ericsons have encapsulated keels and was struck by the narrow profile of this one. If this keel is encapsulated, it's hard for me to believe the narrow profile of the FRP could take the lateral stress induced by the led while heeling. How does it work? Does the lead become a structural component? What would the ratio of lead to FRP be 3/4 down the keel? How day do dat?
Attached Thumbnails
0404131049.jpg   0404131048.jpg   0404131050.jpg  

Last edited by L124C; 04-27-2013 at 07:38 PM.
L124C is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 42 Old 04-27-2013
Oday30!
 
deniseO30's Avatar
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 6,915
Thanks: 55
Thanked 125 Times in 114 Posts
Rep Power: 10
   
Re: Encapsulated Keel?

It is and can be. here's mine. not much bigger.



Denise, Bristol PA, Oday 30. On Tidal Delaware River, Anchor Yacht Club.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


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

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


My boat is sold!
deniseO30 is offline  
Quote Quick Reply Share with Facebook
post #3 of 42 Old 05-06-2013
baDumbumbum
 
bobmcgov's Avatar
 
Join Date: Jul 2007
Location: Windy Wyoming
Posts: 1,126
Thanks: 0
Thanked 36 Times in 35 Posts
Rep Power: 8
 
Re: Encapsulated Keel?

Our Albin Ballad has an integral keel. Even with a 47% ballast ratio, all the lead is in the bottom 32" or so. Which leaves more room for structural FRP & flooring up high, where the stresses are. Think of it this way: the farther down the keel you go, the lower the leverage on the assembly. At the very tip of the keel, the glass only has to support the lead right at that level. Move up six inches, the glass has to carry its lead plus the weight plus the moment arm created by the lead below it. Up another six inches, the glass has to support its lead plus the weight plus the moment arm of the 12" below it. And so on. The trick is to run out of stress (lead + leverage) before your FRP runs out of strength. This is a calculation NAs are quite capable of making.

The difficult aspects come from dynamic loading, which is always a fudge, and in achieving good layups inside a deep, narrow keel or skeg. I haven't heard of too many encapsulated keels tearing off, so presumably they got it approximately right.
L124C likes this.

Buccaneer18, Grainnia
SJ21, Diarmuid
Albin Ballad 30, Fionn
bobmcgov is offline  
Quote Quick Reply Share with Facebook
post #4 of 42 Old 05-06-2013
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 16,518
Thanks: 104
Thanked 309 Times in 299 Posts
Rep Power: 10
     
Re: Encapsulated Keel?

Look in the bilge under the cabin sole... if there are keel bolts then it's a bolt on keel. Tap on the outer surface of the keel.. are you hitting (painted) metal or fiberglass?

I'm sure it's a lead keel, and I was under the impression that that model has a bolt on keel but not positive.

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)
Faster is offline  
Quote Quick Reply Share with Facebook
post #5 of 42 Old 05-06-2013
Senior Member
 
Join Date: Dec 2012
Location: new england
Posts: 2,254
Thanks: 52
Thanked 43 Times in 40 Posts
Rep Power: 3
 
Re: Encapsulated Keel?

Don't know the details of your boat but you can think of it somewhat like a cored hull. Depending on tack one skin is in compression and the other extenson. If glass lay up is not on bias of forces it can easily handle loading. Also some boats use various sub structures to transfer loading to grid structure (stringers etc.) inside hull. Very rigid and strong if done correctly and no issue of keel boat corrosion or metal fatigue concerns. ?Is it an erickson made by PSC. They made great strong boats.

s/v Hippocampus
Outbound 46
outbound is offline  
Quote Quick Reply Share with Facebook
post #6 of 42 Old 05-06-2013
Senior Member
 
Join Date: Jan 2012
Location: British Columbia
Posts: 2,528
Thanks: 20
Thanked 39 Times in 37 Posts
Rep Power: 4
 
Re: Encapsulated Keel?

I once saw a fibreglass boat hauled out in Auckland, which had had an encapsulated lead keel. It hit St Heliers reef, the fibreglass around it had broken, and the lead sunk. The boat floated to her haulout . You could see the neatly broken line, where the fibreglass had cleanly broken around the profile of the lead. Only the fibrglass which was put over the lead had stopped her from sinking.
I'd want a bit more than the fibreglass holding the lead it. Pouring molten lead into fibreglass has to effect the glass.

Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"
Brent Swain is offline  
Quote Quick Reply Share with Facebook
post #7 of 42 Old 05-06-2013
baDumbumbum
 
bobmcgov's Avatar
 
Join Date: Jul 2007
Location: Windy Wyoming
Posts: 1,126
Thanks: 0
Thanked 36 Times in 35 Posts
Rep Power: 8
 
Re: Encapsulated Keel?

Quote:
Originally Posted by Faster View Post
Look in the bilge under the cabin sole... if there are keel bolts then it's a bolt on keel. Tap on the outer surface of the keel.. are you hitting (painted) metal or fiberglass?

I'm sure it's a lead keel, and I was under the impression that that model has a bolt on keel but not positive.
If replying to my post.... The Ballad keel is most certainly integral -- no bolts. You see the light streak running down the keel in this photo?



That's the drain plug in the aft keel sump. The lead ballast starts just below that line.

The Ballad's lead was supposedly laid in place as formed ingots, not hot-poured as with some Morgans. Which method I agree sounds horrible, but many many boats have poured lead keels & again, very few have fallen off. For every example of an integral keel failure you can toss out, Brent, I'll match you with a bolt-on keel failure. There's no surety your Auckland boat would not have lost its keel -- and perhaps its stub -- had it been bolted on. Either attachment method is fine if the engineering was sound and the layup done properly. Jeremy Rogers built Contessa 32s with integral keels. Not a weak boat.

Buccaneer18, Grainnia
SJ21, Diarmuid
Albin Ballad 30, Fionn
bobmcgov is offline  
Quote Quick Reply Share with Facebook
post #8 of 42 Old 05-07-2013
grumpy old man
 
Join Date: Apr 2011
Posts: 4,128
Thanks: 1
Thanked 96 Times in 92 Posts
Rep Power: 5
 
Re: Encapsulated Keel?

I have done many internally ballasted, "encapsulated keel" or "integral keel" boats. I've done a similar number of bolt on lead keels. Either way done correctly is fine. I like bolt on from a designj perspective because it gives me a free hand in shaping the ballast. With an integral keel you shape and foil distribution has to be suxch that you can pull the boat from the mold. Ionce poured hot lead into an integral GRP keel on my own half tonner. It worked fine. That boat is still around.

Once again, generalizations about a keel type are silly. If the boat is well designed and well built either an integral or bolt on keel will be fine. With all my designs with integral keels I cannot think of one that has had a keel problem and I would estimate I'm talking about over 2,000 boats. Maybe there has been a few but I have never heard about them.
But, when there is a problem like a keel failure I am usually one of the first to be called.
L124C likes this.

Please visit my blog. It's fun to read.


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

Bob's Blog ....

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


Please also visit my new web site
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
bobperry is offline  
Quote Quick Reply Share with Facebook
post #9 of 42 Old 05-07-2013
Senior Member
 
Join Date: Mar 2012
Posts: 663
Thanks: 27
Thanked 25 Times in 24 Posts
Rep Power: 4
 
Re: Encapsulated Keel?

Bruce King boats have both internal and external ballast depending on year and model. Most of his older boats had internal ballast glassed in and bolted to discourage shifting of the lead so you may see bolts on internally ballasted boats.
barefootnavigator is offline  
Quote Quick Reply Share with Facebook
post #10 of 42 Old 05-07-2013
Oday30!
 
deniseO30's Avatar
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 6,915
Thanks: 55
Thanked 125 Times in 114 Posts
Rep Power: 10
   
Re: Encapsulated Keel?

Bob how great in layperson's terms are the lateral stresses on keels?

Denise, Bristol PA, Oday 30. On Tidal Delaware River, Anchor Yacht Club.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


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

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


My boat is sold!
deniseO30 is offline  
Quote Quick Reply Share with Facebook
Reply

Tags
encapsulated keel , ericson

Quick Reply
Message:
Options

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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Encapsulated or Bolt On Keel? aasault Boat Review and Purchase Forum 46 05-12-2015 04:00 PM
Crack in front of encapsulated keel FishFinder Gear & Maintenance 19 04-29-2013 12:09 PM
encapsulated keel 83XT4 Pacific Seacraft 13 01-09-2010 08:14 PM
Electrical Grounding for an Encapsulated Keel? MedSailor Gear & Maintenance 5 07-10-2009 07:28 PM
encapsulated keel leaking to bilge jbrockpiano Gear & Maintenance 20 06-12-2008 11:43 AM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome