Would your keel joint survive a full speed impact? - Page 3 - 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 > General Discussion (sailing related)
 Not a Member? 


Like Tree1Likes
Reply
 
LinkBack Thread Tools
  #21  
Old 01-03-2012
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,896
Thanks: 2
Thanked 103 Times in 100 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
"until things start to blow "
Yes, the I28 gets outright talkative at 40 knots, you can hear each piece of the boat as it hands off the load from every surge down through the mast to the keel. Kinda like a big dog walking through a pond, shaking it all off and saying "What?" when you complain about the splatter.
Who wants to sail in under five knots anyway? (VBG)
Reply With Quote Quick reply to this message Share with Facebook
  #22  
Old 01-03-2012
Senior Member
 
Join Date: Feb 2010
Location: Narragansett Bay
Posts: 9,502
Thanks: 10
Thanked 159 Times in 145 Posts
Rep Power: 6
Minnewaska will become famous soon enough Minnewaska will become famous soon enough
Quote:
Originally Posted by msmith10 View Post
I know the boat. She didn't hit sand-- she hit rocks under power at considerable speed. Impact was enough to tear the engine and generator off their mounts. Yes, it was repaired, at over $200k in costs, but it's not a boat I'd buy.
Correction: It may not be the same boat. There is a Yachtworld listing that is not the boat I'm referring to.
Same story, though.
I am told it is one of the boats out on yachtworld. Ive never seen it, but was told the story by a surveyor that I used on mine.

I cant imagine the damage if we rammed our keel into rocks at full throttle. 40,000+ lbs at 8 to 9 kts and a dead stop in inches. Says something that it reportedly stayed afloat. It had to have been towed in, but I don't know.
__________________

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
  #23  
Old 01-03-2012
SloopJonB's Avatar
Senior Moment Member
 
Join Date: Jun 2011
Location: West Vancouver B.C.
Posts: 10,934
Thanks: 58
Thanked 56 Times in 53 Posts
Rep Power: 4
SloopJonB will become famous soon enough
Quote:
Originally Posted by Faster View Post
One of the largest factors will be keel material. Lead absorbs an amazing amount of energy as it deforms under impact. Iron keels do not and transfer the full forces to the hull - therefore internal damage is likely to be more significant with iron keels.
The designer Bill Garden said the opposite in one of his yacht design books. His opinion was that lead would crush and "form" around the obstruction and as a result, the boat would absorb the full energy of the impact. Iron, on the other hand would tend to bounce off the obstruction and not absorb the same amount of energy. He preferred iron on boats that would sometimes have to "feel" their way into anchorages.

I have seen or experienced both and I tend to agree with Garden. I hit a rock at full speed with a lead fin keel - the boat stopped dead, crew were thrown off their feet, minor injuries etc. The boat survived intact but I had an 8" square area of the toe of the keel to fill and fair on the next haulout.

On the other hand, I was looking out over English Bay one evening from a bluff in Kitsilano, watching a 33'ish wooden motorsailor motoring by fairly near shore. All of a sudden there was a very audible CLANG and the boat jumped about a foot. The skipper merely turned a few degrees offshore and just kept on truckin' - completely unruffled - no crew flying about, no drama, just an almighty CLANG, clearly audible from at least 300 yards.

I saw that long before I read Garden's book and immediately thought of it when I did - his words completely agreed with what I witnessed (and later experienced).

Also, when I was redoing the iron keel on my current boat, on the toe of the keel there were a number of 1/4" deep gouges in the toe area - the boat had been through El Caribe from New York to L.A. and had apparently hit some coral or something - 1/4" deep gouges in SOLID IRON - how much force did that take? It left a lot less damage than the lead incurred on my old boat.

As to the OP's question, I am confident my iron keel can withstand a hard hit. It has a 1' wide, 10' long flange along the top with a double row of studs spaced 10" apart laterally. For those familiar with the Thunderbird, it is not unlike how their keels are mounted. The whole thing fits up into a 1 1/2" deep rabbet moulded into the hull. The bottom above it at that point is 2" thick. On the inside, each pair of studs passes through a piece of 2" X 4" X 24" stainless channel with thick fender washers and double nuts on each stud. There are also 8" timber "floors" glassed into the bottom between every other stainless channel.

I think it can take a hit.
__________________
I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
Reply With Quote Quick reply to this message Share with Facebook
  #24  
Old 01-03-2012
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,539
Thanks: 13
Thanked 149 Times in 115 Posts
Rep Power: 15
Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
Quote:
Originally Posted by hellosailor View Post
down, the I28 is built like a brick *house, it isn't easy to break one. But AFAIK there is no keel designed to take hard impacts without structurl damage to the boat. Either you tear the keel off, or the hull lets go, the amount of force involved in a "head on" collision is going to wrinkle the boat. Even if you kept the keel on, the rig would probably be damaged and the bulkheads come untabbed--on any boat.
Coming from Maine the land of GRANITE ledges we see LOTS of boats hit rocks each year. If I had to guess I'd say in the 150 -250 hard groundings per year. I know of ONE keel the fell off over the last 20 years. It was a J Boat. In one week two years ago I watched 8 boats get hauled at the same yard for "ledge damage inspection".. I'm always perplexed how so many folks find these ledges but they do..

The worst and longest repairs I see are encapsulated keels or fins on quite lightly built boats because there can be structural damage. I once watched an Island Packet drain water from the keel encapsulation (cement) for over 7 weeks and it was still far from dry when the out of state owners hauled it away on a truck. During the time the IP was drying two or three fin keelers were hauled ground, filled, faired and re-launched..

I would have to say the a large percentage of groundings in Maine result in not much more than some dents and dings in the lead.

I had two of my customers hit ledges this summer alone and both were at full tilt and one with an SOG of about 7.2 - 7.3 knots. He hit solid granite and people aboard were bruised. The keels were mashed and the keel hull joints will be ground & faired, the lead dents fixed and they will be fine for many more years. Structural damage is non-existent on either of these boats one is an 82 Sabre 34 MKI and the other an 87 Ericson 32. Both of these boats were deep fins not shoal..

Many fin keel boats hit granite here in Maine with no structural damage and only lead dents and perhaps some cracking of the keel hull fairing putty. While some do have structural damage sinkings and keels ripping off are very rare.

These folks found the ledge and had to wait out the tide..
__________________
______
-Maine Sail / CS-36T


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




© Images In Posts Property of Compass Marine Inc.



Last edited by Maine Sail; 01-03-2012 at 08:44 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #25  
Old 01-04-2012
Barquito's Avatar
Barquito
 
Join Date: Dec 2007
Location: Madison, WI
Posts: 2,078
Thanks: 0
Thanked 18 Times in 18 Posts
Rep Power: 8
Barquito is on a distinguished road
This has been an eye opening thread for me. I really don't like the idea of looking and wondering if keelbolts are rusting, and moderatly don't like the idea of replacing keel boats. Therefore, I went with an encapsulated keel design. However, I can now see the argument for bolt-on keels. What about adding a really thick 'skid plate' to the nose of an encapsulated keel?

Also, it is obvious that bigger boats are stonger, but, it seems the force of a full speed hit in a large boat would be orders of magnitude larger than in a small boat. The keel lever arm is longer, the weight of the boat is larger, and the top speed of the boat is greater. Are deep draft, heavy, big-boats built THAT strong?
Reply With Quote Quick reply to this message Share with Facebook
  #26  
Old 01-04-2012
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,896
Thanks: 2
Thanked 103 Times in 100 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
A skid plate only works by deflecting what it is attached to. You'd have to run it from the bow to the bottom of the keel, so you could skid up over whatever you hit. And it would have to be built and attached strong enough to allow that shift up and over. That would be a lot of weight, and you'd probably still trash the rig and bulkhead tabbing when you hit.

Easier to just stay in clear water.
Reply With Quote Quick reply to this message Share with Facebook
  #27  
Old 01-04-2012
tommays's Avatar
Senior Member
 
Join Date: Sep 2008
Posts: 4,282
Thanks: 1
Thanked 29 Times in 29 Posts
Rep Power: 7
tommays will become famous soon enough
On my friends Tartan 372 when they hit the Ledge in Maine the biggest issue was breaking all four Volvo motor mounts as the motor is under the kitchen sink its a bit of chore
__________________
1970 Cal 29 Sea Fever

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

1981 J24 Tangent 2930
Tommays
Northport NY


If a dirty bottom slows you down what do you think it does to your boat
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #28  
Old 01-04-2012
Nearly an Old Salt
 
Join Date: Oct 2008
Posts: 264
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 7
goboatingnow is on a distinguished road
have a look at

Crash Test - Dehler 31 yacht - YouTube
Reply With Quote Quick reply to this message Share with Facebook
  #29  
Old 01-04-2012
DelmarRey's Avatar
Senior Member
 
Join Date: Aug 2001
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
DelmarRey is on a distinguished road
Oh No!

Now I need a T-shirt that says "I survived a hard grounding".
Attached Thumbnails
Would your keel joint survive a full speed impact?-keel2_09.jpg  
__________________
"Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful!"


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #30  
Old 01-04-2012
downeast450's Avatar
Tundra Down
 
Join Date: Jan 2008
Location: Seal Harbor, Maine
Posts: 1,252
Thanks: 33
Thanked 18 Times in 18 Posts
Rep Power: 7
downeast450 is on a distinguished road
Maine,

I am amazed at that number of hard groundings / year. I spend much of the sailing season along the Maine coast and have many friends who sail here. I only know of two hard hits around MDI in the past few years. I guess I don't know as many sailors as I thought. My sailing friends are "locals". Is the carnage you mention happening to boats from "away"? There are not that many "hidden" spots if the skipper is competent.

Down
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
Full Keel Vs. Fin or Modified Full Keel AjariBonten Sailboat Design and Construction 51 11-16-2013 03:52 AM
Full Keel vs. Wing Keel small boats Kyhillbilly General Discussion (sailing related) 4 07-26-2011 12:51 PM
Rusty spots on keel and hull keel joint Stephane99 Gear & Maintenance 1 04-07-2009 08:39 PM
Keel Joint on Hunter 25.5 neil123 Gear & Maintenance 1 03-23-2005 07:49 PM
O''Day 302 Keel Joint mittelman Gear & Maintenance 0 02-05-2002 05:56 PM


All times are GMT -4. The time now is 10:25 PM.

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.