PSA - Check your through hulls BEFORE launch

eherlihy

eherlihy

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Aug 17, 2010
330
Oday 35 Barrington
In preparation for another season, I took a close look at the above the waterline plastic through hull fittings on my O'day 35. I was shocked to see that ALL of them had cracks, and would have leaked if I have launched the boat. I have replaced the 1½" manual bilge pump discharge and the cockpit drains with 316 stainless steel through hulls, so I shouldn't have to worry about them again. I also replaced the 3/4" shower sump discharge with a stainless steel fitting. The rest (both propane locker discharges and lavatory sink discharge) are Perko 5/8" through hulls.

If you do this, make sure that you have a tube (or two) of 3M 4200 Fast Cure for bedding the through hulls.
 
Davidasailor26

Davidasailor26

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May 17, 2004
5,709
Beneteau Oceanis 37 Havre de Grace
Good reminder. O’Day did use a lot of nylon mushroom fittings for above the waterline thru hulls like that. They also didn’t put seacocks on anything above the waterline, not that a seacock will help if the thru hull itself fails. The nylon is good for a while but does eventually chalk and weaken.
 
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Tally Ho

Tally Ho

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Jan 7, 2011
5,668
Oday 322 East Chicago, IN
jviss said:
Is this correct, or did you mean below the waterline?
Click to expand
Just cause it is above the static waterline doesn’t mean it will stay there:yikes:

And many builders used plastic barbed through hulls in these locations.

On my 38 year old O’Day 322, I found the same conditions…and I replaced all of my scupper drain thru hulls, vanity sink, propane lockers, bilge pump thruhulls…all were at or slightly above the static waterline…but under water a lot of time while under sail.

Greg
 
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L

LouisMK

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Aug 7, 2015
117
Oday 34 previous, O’Day 40 current Annapolis
Rather than metal you should consider the modern day plastics by ThruDesign (gemlux.com) They have backer plates which are required by the ABYAC for below the waterline installations. Their service is exceptional, the quality is fantastic and their backer plates are more easily installed than adding wood backers. I’m in the process of doing this in my O’40 and I’ve found plenty of thuhulls that are no longer needed and you be able to see if there is moisture getting into the hull in this area.In my experience you’ll spend three times the mount of time to remove the existing compared to the install time for new.
 
L

LouisMK

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Aug 7, 2015
117
Oday 34 previous, O’Day 40 current Annapolis
Also, I used Sika 291-I which is pretty easy to work with. I got tired of my el-cheapo caulking gun & bought a $25 upgrade at the Depot. Never thought I’d spend that kind of money on a caulking gun, but what a difference! Also, if you are using metal thruhulls, please make sure they’re bonded to the grounding system, Plastic, no worry!
 
jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
You know, this has me thinking. I have "outlets" to the water, just above the waterline and that would certainly be in the water a lot when sailing, that don't have through-hulls, per se. They are just holes in the hull that are backed with molded-in 'sea chests,' boxes that have one or two hose flanges facing up, to which are attached hoses to deck scuppers, bilge pumps, etc. I suspect it's remotely possible they could become cracked and leak at some point. I don't even know how to get an eyeball on them. Now I won't be able to sleep! Thanks a lot! :)
 
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LouisMK

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Aug 7, 2015
117
Oday 34 previous, O’Day 40 current Annapolis
Stainless probably works though you need to make sure they are securely connected to the bonding system
 
Tally Ho

Tally Ho

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Jan 7, 2011
5,668
Oday 322 East Chicago, IN
jviss said:
You know, this has me thinking. I have "outlets" to the water, just above the waterline and that would certainly be in the water a lot when sailing, that don't have through-hulls, per se. They are just holes in the hull that are backed with molded-in 'sea chests,' boxes that have one or two hose flanges facing up, to which are attached hoses to deck scuppers, bilge pumps, etc. I suspect it's remotely possible they could become cracked and leak at some point. I don't even know how to get an eyeball on them. Now I won't be able to sleep! Thanks a lot! :)
Click to expand
Sorry @jviss,

Didnt mean to start your night terrors!

I had 8 original nylon drains (can’t really call them thru hulls). They were all right above the water line. I could remove the hose and not flood the boat if I was sitting in the slip, but many (particularly the 4 in the stern) when the rear squats under power, or the ones on the sides when healed over…

IMG_1761.png IMG_1760.png IMG_1763.png IMG_1762.png

One caveat to all who replace this sort of fitting…the hole sizes have changed for some sizes, for the same hose bard size…

I had to drill larger holes for some sizes, and I had 2 that I thought I might need to epoxy over the hole and redrill to make it smaller :facepalm:. I ended up not doing that, and they seem fine, but it was close.

sweet dreams :yikes:


Greg
 
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jviss

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
Tally Ho said:
Sorry @jviss,

Didnt mean to start your night terrors!

I had 8 original nylon drains (can’t really call them thru hulls). They were all right above the water line. I could remove the hose and not flood the boat if I was sitting in the slip, but many (particularly the 4 in the stern) when the rear squats under power, or the ones on the sides when healed over…

View attachment 215864 View attachment 215865 View attachment 215866 View attachment 215867

One caveat to all who replace this sort of fitting…the hole sizes have changed for some sizes, for the same hose bard size…

I had to drill larger holes for some sizes, and I had 2 that I thought I might need to epoxy over the hole and redrill to make it smaller :facepalm:. I ended up not doing that, and they seem fine, but it was close.

sweet dreams :yikes:


Greg
Click to expand
I just found the admittedly abstract and vague plumbing diagram for my boat in the manual, and it indicates that there's a vented loop before the sea chest; though that won't help if the sea chest flange fails. Now, if I only knew where to find these things.... I should look for them, based on where the outlets appear on the hull.
 
eherlihy

eherlihy

.
Aug 17, 2010
330
Oday 35 Barrington
The through hulls for the bilge pump, cockpit drains (scuppers), propane locker, head sink drain, and shower sump discharge, are all ABOVE the waterline. None of these are tied to the bonding system, as it is not required by ABYC. The relevant ABYC standards are E-2 (Cathodic Protection), E-11 (AC and DC Electrical Systems on Boats), H-27 (Seacocks, Thru-Hull Fittings, and Drain Plugs), and TE-4 (Lightning Protection).

20230518_140420.jpg
 
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Tally Ho

Tally Ho

.
Jan 7, 2011
5,668
Oday 322 East Chicago, IN
jviss said:
You know, this has me thinking. I have "outlets" to the water, just above the waterline and that would certainly be in the water a lot when sailing, that don't have through-hulls, per se. They are just holes in the hull that are backed with molded-in 'sea chests,' boxes that have one or two hose flanges facing up, to which are attached hoses to deck scuppers, bilge pumps, etc. I suspect it's remotely possible they could become cracked and leak at some point. I don't even know how to get an eyeball on them. Now I won't be able to sleep! Thanks a lot! :)
Click to expand
I would like to see a photo of that “ sea chest”…I don’t know exactly what that is.

Greg
 
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