Replacing thru hull - SailNet Community

   Search Sailnet:

 forums  store  

Quick Menu
Boat Reviews  
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Hatches and Portlights
Interior And Galley
Marine Electronics
Other Items
Plumbing and Pumps
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here

Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
Old 07-11-2007
saurav16's Avatar
Senior Member
Join Date: Mar 2007
Location: NY
Posts: 312
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
saurav16 is on a distinguished road
Send a message via AIM to saurav16
Replacing thru hull


The surveyor said that I have to replace the thru hulls on my 79 catalina 27 as they have the garden variety gate valve thus I need to use a marine ball valve. To do this I need to also add a vinyl nipple which I posted about before. However when I hauled the boat out last week to do my cutlass bearing I noticed the boat doesn't have the bronze nipples on the out side of the holes. It is just a hole drilled into the hull of the boat no nipple or anything. Is this common for older boats? I looked at an old columbia at the yard and it had the same thing for the thru hull. There was no nipple on the outside just a hole.

If this is the case to install a nipple when swapping the sea cocks do I just drill the hole out bigger since there is no nipple or is there a nipple under the glass in the hull? Sorry if I am not explaining this well. I wish I had taken a picture.
Reply With Quote Quick reply to this message Share with Facebook
Old 07-11-2007
Join Date: Jun 2007
Posts: 91
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
rhaley is on a distinguished road
The Catalina "thru-hulls" are just bronze pipes glassed into those holes you see from the outside. They should be threaded and the gate valve will unscrew from the pipe and a ball valve will screw on. That is assuming that you can just unscrew the gate valve, which depending on the condition of the pipe and valve, may not be possible.

With that said, since the boat is out of the water, replacing the pipes with real thru-hulls is the right way to do the job, IMHO. In my case, I just used a hole saw the proper size for the new thru-hull and centered it over the old bronze hole and cut it all out in one shot. On another Catalina, to help keep the hole saw centered, I have hammered in a wooded plug (from the outside), cut it off flush, and used a hole saw with a center drill bit in the wooden plug. Good Luck!
Reply With Quote Quick reply to this message Share with Facebook
Old 07-11-2007
Join Date: Apr 2001
Posts: 55
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
robfinora is on a distinguished road

Yes - that is normal on older Catalinas - but not the correct way to make a thru-hull. What Catalina did was just drill out a hole in the hull and then glassed a bronze pipe directly in the hole. Then they built up glass and resin all around the pipe to form what looks like a "volcano". You should really replace all of them on the boat if thats how they were done (I guess your surveyor would have told you that as well). You will need a grinder and if you have a sawzal - use that as well. Cut off the bronze pipe close to the hole as possible and then grind out everything else. You may want to considor using a hole-saw slightly larger than the pipe to drill out the remaining piece glassed in and then install a slightly larger thru-hull fitting. Make sure you create a backing plate out of marine-grade plywood when installing the new one.

I hear its not that big of a job. Do some archive searches in the forum for thru-hull installation - there are lots of posts on the subject. I just replaced one of mine a few weeks ago.
Reply With Quote Quick reply to this message Share with Facebook

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


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
High Tech vs traditional-Comments? Pangaea General Discussion (sailing related) 38 08-07-2007 01:07 AM
Spring Hull Cleaning Tom Wood Gear and Maintenance Articles 0 04-05-2004 08:00 PM
New Shine for an Old Hull Don Casey Gear and Maintenance Articles 0 01-08-2002 07:00 PM
Hull Speed Demystified Steve Colgate Learning to Sail Articles 0 06-10-2000 08:00 PM
Hull Speed Demystified Steve Colgate Buying a Boat Articles 0 06-10-2000 08:00 PM

All times are GMT -4. The time now is 02:26 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) LLC 2000-2012

The store is owned and operated by a company independent of the forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.