Sealing through hulls in balsa cored boat - 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 > On Board > Gear & Maintenance
 Not a Member? 


Like Tree1Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 04-05-2013
Junior Member
 
Join Date: Apr 2013
Posts: 18
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
liveitwell is on a distinguished road
Sealing through hulls in balsa cored boat

Ive recently purchased a dreadnought 32 with a balsa cored hull. There are two gate valves in the head that are fairly corroded and have me a bit concerned. Im planning to haul to boat out and remove these Valves as well as glass over the thru hulls. My reserach has found that a 12-1 taper is to be ground into the edge of the thru hull in order to prepare it for glassing. My question is how to put this taper into the holes when there less than a foot apart and if its a differnt proccess to glass over a through hull thats into a balsa core. Ive done a bit of deck repair already with polyesther resin. but nothing under the waterline like this. I want to make sure I do the best job possible so any advise anyone could give me on what materials to use and how to go about it would be a great help. Thank you much.
Attached Thumbnails
Sealing through hulls in balsa cored boat-2013-04-05-160719.jpg  
Reply With Quote Share with Facebook
  #2  
Old 04-06-2013
Senior Member
 
Join Date: Jan 2011
Location: Maine
Posts: 598
Thanks: 0
Thanked 17 Times in 17 Posts
Rep Power: 4
DonScribner is on a distinguished road
Re: Sealing through hulls in balsa cored boat

LiveIt,

The 12:1 is probably referring to the thickness of the fiberglass so if it's 1/4" thick, taper it 12/4 or 3" to each side. This allows the application of a series of circles of fiberglass that increase in size each sequential layer until they reach full size. Before you do this, plug the balsa hole with filler and be sure to taper both inside and outside holes properly.
Reply With Quote Share with Facebook
  #3  
Old 04-09-2013
zz4gta's Avatar
I don't discuss my member
 
Join Date: Aug 2007
Location: Chesapeake Bay
Posts: 2,444
Thanks: 0
Thanked 16 Times in 16 Posts
Rep Power: 8
zz4gta is on a distinguished road
Re: Sealing through hulls in balsa cored boat

liveitwell, grind out your 12:1 the best you can with the room you have. If you want you can even sand down that stringer (just enough to get the paint off) and put a piece of cloth that overlaps that. Basically, the 12:1 is best case senerio. I only had a 6" diameter area to work with a hole that was 3/4"-1" thick, so my bevel turned out to be 6:1 roughly. 4 years and countless waves, and it doesn't leak a drop. I just beveled it from the inside.

I understand what the book says and why it says it, but sometimes you have to do the best you can w/ what you got.
__________________
Merit 25 # 764 "Audrey"
Reply With Quote Share with Facebook
  #4  
Old 04-09-2013
msmith10's Avatar
Junior member, rest old
 
Join Date: Feb 2009
Location: Columbus Ohio
Posts: 492
Thanks: 3
Thanked 0 Times in 0 Posts
Rep Power: 6
msmith10 is on a distinguished road
Re: Sealing through hulls in balsa cored boat

The core should be handled like you would a penetration of the deck core: take the coring back between the glass layers, seal the coring edges with thin epoxy, then replace the coring with thickened epoxy. Now glass over.
There's a good illustration of this here: http://www.wbryant.com/StellaBoat/index.htm
Go to the "Haulouts" tab.
__________________
Mark Smith
1977 C&C 30 Mk 1 hailing from Port Clinton, Ohio

Last edited by msmith10; 04-09-2013 at 01:16 PM.
Reply With Quote Share with Facebook
  #5  
Old 04-09-2013
CalebD's Avatar
Tartan 27' owner
 
Join Date: Jan 2008
Location: NYC
Posts: 4,551
Thanks: 4
Thanked 87 Times in 80 Posts
Rep Power: 7
CalebD will become famous soon enough
Re: Sealing through hulls in balsa cored boat

I'd use epoxy as it has better adhesive qualities than polyester.

You may find this article useful: Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Compass Marine at pbase.com
__________________
"The cure for anything is salt water~ sweat, tears, or the sea." ~Isak Denesen

Everybody has one:

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
  #6  
Old 04-10-2013
Junior Member
 
Join Date: Oct 2012
Location: Toronto
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
whippet99 is on a distinguished road
Re: Sealing through hulls in balsa cored boat

Hi

West Systems has great online resources (and many mentions of cases like yours)

Forum wont let me post url -- but go to westsystem.com / ss / use-guides
Reply With Quote Share with Facebook
  #7  
Old 04-10-2013
Senior Member
 
Join Date: Apr 2008
Posts: 453
Thanks: 12
Thanked 16 Times in 16 Posts
Rep Power: 7
Hudsonian is on a distinguished road
Re: Sealing through hulls in balsa cored boat

Go to epoxyworks.com for comprehensive answers to this question. Then: Articles by subject; Boat repairs and restoration;Repairing machined holes in fiberglass. Epoxyworks is a West pubblication.
Reply With Quote Share with Facebook
  #8  
Old 04-10-2013
Junior Member
 
Join Date: Apr 2013
Posts: 18
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
liveitwell is on a distinguished road
Re: Sealing through hulls in balsa cored boat

Thanks for the info folks, keep it coming its a great help! Ive got a better idea of how to go about it now. Ive also been doing lots of tapping to try and detect any delamination, tricky below the waterline. Seems like it might not be as bad as I imagined, though i can be an optimist... Any more info is welcome you folks are great, thank you.
Reply With Quote Share with Facebook
  #9  
Old 04-10-2013
Liquorice's Avatar
Senior Member
 
Join Date: Nov 2007
Location: Alberta, Canada
Posts: 163
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 7
Liquorice is on a distinguished road
Re: Sealing through hulls in balsa cored boat

I may be completely out to lunch here - , but the engineer in me says the 12:1 should be on the outside!
Logic tells me the pressure is pushing outside ->in when the boat is in the water. So shouldn't the wedge be on the outside so water pressure tends to hold the plug in place more firmly?
Never done this, but that would be my first thought.
Sam :-)
__________________
sam :-)
Just because you're paranoid ...doesn't mean they're not after you!
Reply With Quote Share with Facebook
  #10  
Old 04-10-2013
msmith10's Avatar
Junior member, rest old
 
Join Date: Feb 2009
Location: Columbus Ohio
Posts: 492
Thanks: 3
Thanked 0 Times in 0 Posts
Rep Power: 6
msmith10 is on a distinguished road
Re: Sealing through hulls in balsa cored boat

Quote:
Originally Posted by Liquorice View Post
I may be completely out to lunch here - , but the engineer in me says the 12:1 should be on the outside!
Logic tells me the pressure is pushing outside ->in when the boat is in the water. So shouldn't the wedge be on the outside so water pressure tends to hold the plug in place more firmly?
Never done this, but that would be my first thought.
Sam :-)
Hopefully you're not relying on water pressure to hold anything in place. The 12:1 feather is to get good bonding of the new glass to the old, so you want it on both interior and exterior.
__________________
Mark Smith
1977 C&C 30 Mk 1 hailing from Port Clinton, Ohio
Reply With Quote Share with Facebook
Reply


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
Balsa cored hulls bjung Sailboat Design and Construction 27 02-11-2013 03:41 PM
1980's Sabre balsa cored hulls grande4 Boat Review and Purchase Forum 22 11-19-2010 02:41 PM
Which C&C sailboats have balsa cored hull? alexsails Boat Review and Purchase Forum 26 06-08-2010 05:51 AM
Balsa Cored hull Bardo Boat Review and Purchase Forum 40 08-29-2007 10:53 AM
Balsa cored hulls - old boats gstraub Boat Review and Purchase Forum 20 02-21-2003 05:08 PM


All times are GMT -4. The time now is 12:54 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

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.