Encapsulated Keel? - 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 > General Interest Forums > Boat Review and Purchase Forum > Sailboat Design and Construction
 Not a Member? 


Like Tree6Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 04-27-2013
L124C's Avatar
Senior Member
 
Join Date: Oct 2007
Posts: 1,330
Thanks: 33
Thanked 2 Times in 2 Posts
Rep Power: 7
L124C is on a distinguished road
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
Encapsulated Keel?-0404131049.jpg   Encapsulated Keel?-0404131048.jpg   Encapsulated Keel?-0404131050.jpg  

Last edited by L124C; 04-27-2013 at 07:38 PM.
Reply With Quote Share with Facebook
  #2  
Old 04-27-2013
deniseO30's Avatar
Move over Joan Rivers!
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 5,487
Thanks: 50
Thanked 55 Times in 47 Posts
Rep Power: 9
deniseO30 will become famous soon enough deniseO30 will become famous soon enough
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. New Website!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

my current "project"!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #3  
Old 05-06-2013
bobmcgov's Avatar
baDumbumbum
 
Join Date: Jul 2007
Location: Windy Wyoming
Posts: 1,000
Thanks: 0
Thanked 20 Times in 19 Posts
Rep Power: 7
bobmcgov will become famous soon enough
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
Reply With Quote Share with Facebook
  #4  
Old 05-06-2013
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 14,390
Thanks: 63
Thanked 160 Times in 157 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
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)
Reply With Quote Share with Facebook
  #5  
Old 05-06-2013
Senior Member
 
Join Date: Dec 2012
Location: new england
Posts: 1,468
Thanks: 30
Thanked 23 Times in 20 Posts
Rep Power: 2
outbound is on a distinguished road
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
Reply With Quote Share with Facebook
  #6  
Old 05-06-2013
Senior Member
 
Join Date: Jan 2012
Location: British Columbia
Posts: 2,249
Thanks: 6
Thanked 28 Times in 27 Posts
Rep Power: 3
Brent Swain is on a distinguished road
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"
Reply With Quote Share with Facebook
  #7  
Old 05-06-2013
bobmcgov's Avatar
baDumbumbum
 
Join Date: Jul 2007
Location: Windy Wyoming
Posts: 1,000
Thanks: 0
Thanked 20 Times in 19 Posts
Rep Power: 7
bobmcgov will become famous soon enough
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
Reply With Quote Share with Facebook
  #8  
Old 05-07-2013
grumpy old man
 
Join Date: Apr 2011
Posts: 3,346
Thanks: 1
Thanked 68 Times in 64 Posts
Rep Power: 3
bobperry will become famous soon enough
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.
Reply With Quote Share with Facebook
  #9  
Old 05-07-2013
barefootnavigator's Avatar
Senior Member
 
Join Date: Mar 2012
Location: Salish Sea
Posts: 533
Thanks: 21
Thanked 20 Times in 20 Posts
Rep Power: 3
barefootnavigator is on a distinguished road
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.
Reply With Quote Share with Facebook
  #10  
Old 05-07-2013
deniseO30's Avatar
Move over Joan Rivers!
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 5,487
Thanks: 50
Thanked 55 Times in 47 Posts
Rep Power: 9
deniseO30 will become famous soon enough deniseO30 will become famous soon enough
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. New Website!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

my current "project"!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
Reply

Tags
encapsulated keel , ericson


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
Crack in front of encapsulated keel FishFinder Gear & Maintenance 19 04-29-2013 12:09 PM
Encapsulated or Bolt On Keel? aasault Boat Review and Purchase Forum 34 06-19-2011 09:20 AM
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


All times are GMT -4. The time now is 02:21 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