O'Day 25 Shoal Draft Centerboard Water Leak

May 14, 2012
68
Oday 25 Shoal draft Mystic
My keel has water trapped inside of it. I found that I had a missing screw on one of the plates- starboard side- that hold the centerboard axle wedges in place. The screw thread was stripped out. I removed the other screw on that side and alot of water came out. When I blow into the screw hole, I can hear there is a cavity in there. On the port side, both screws were in place, one came out easily and the other broke at the screw head. No water came out from that side. The fasteners are 1/4-20 SS flat heads, 2 in each plate. When I tried to dremel the broken screw head, the carbide bit would not penetrate it.
In the bilge, there are some rough areas of glasswork forward of the center beam, but mostly smooth epoxy coated glass. There must be a hole or crack that isn't visible, that bilge water is penetrating. I get water inside mostly when heady rain, wind forces through the companionway.
Does anyone know how the keel is constructed to give me some direction on how to further drain and fill the void in the keel? I couldn't tell what material the threads were cut into, fiberglass or a threaded insert? Since the area was wet, I couldn't get a good look to tell. I will return to the boat tomorrow, it should be dry enough to see.
 

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Mar 2, 2019
433
Oday 25 Milwaukee
From experience ,it appears you have two separate concerns . The shoal draft keel is completely sealed off from the bilge . our shoal draft ,an '81 is lead encased .
Never the less water got into the bilge from a number of places . The biggest and easiest to resolve was the fresh water tank .
The gutter drains for the cockpit seats need to be kept clear of debris . Otherwise any rain water drains into the bilge way back under the cockpit . Some folks have had the tube for the centerboard pendant leak . The cooler drain hose that joins the sink may also lead to water in the bilge. Seal the chain plates and monitor all the bulkheads for water stains . I hope this helps
 
May 14, 2012
68
Oday 25 Shoal draft Mystic
Besides the wind driven rain entering around the companiomway, I believe that water enters from the cockpit as there is usually water in the area under the sink. The boat is very clean and no buildup of debris around any drainage areas. I have a tarp on the aft section now as I want to dry it out as best possible.
 
May 14, 2012
68
Oday 25 Shoal draft Mystic
I used low air pressure to leak check the bilge. I cut the head off of a bolt and drilled a hole through it and screwed it into one of the centerboard plate holes and attached the air line to it. I found leaks in the corners of the trunk and around the mast post. I set up a fan and heater inside and fight the good fight of drying out a bilge for fiberglass repair. The cavity still has salt water dripping out of it. I believe the threaded inserts for the centerboard plates are brass. One is stripped and one has a broken screw in it. I tried to tap out the screw with a small tungsten rod, tapping in a circular motion but its stuck.
 

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May 14, 2012
68
Oday 25 Shoal draft Mystic
This pic shows the soap bubble better at the mast post. The other shows blue leak detector coming back out of the bilge from the air pressure, and soap bubbles in the corner of the centerboard trunk and bilge bottom.
 

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Mar 2, 2019
433
Oday 25 Milwaukee
Wow .I had no idea the bolts were that close to the bilge . Makes me wonder about my own boat now ...
 
May 14, 2012
68
Oday 25 Shoal draft Mystic
I talked to Rudy at D&R Marine, he told be that the threads are in 1 x 1 brass plates glassed in. I brought a few end cutting dremel bits, I will try to cut the broken screw out and retap that hole and the stripped hole with 5/6-18 threads. I found the bits and 316 SS screws on mcmaster-carr.com. the bilge glasswork shouldn't be too hard to do as long as I can can keep it warm and dry in there. I have a fan and heater set up inside.
 
Jul 24, 2020
12
Catalina Capri 16.5 Bass River
I have basically the same issue. I removed three of the machine screws without issue but the head of the fourth got messed up. I used a grinder to cut of the head so I could then slip the plate off. Then I used a 3/16" drill bit to drill around the bolt stub and pulled it with needle nosed pliers.

Next, in order to clean the hole I ran a large drill up in preparation for repairing the hole and insert. As I drilled suddenly it pushed through and water started to run out. It seems that the hole should only penetrate to a certain depth. The plate is about 2ft below the bottom of the bilge so I was surprised that water had penetrated down into the stub keel.

My plan is to epoxy in a new brass plate or nut. First I will force enough epoxy up into the hole then insert the machine screw and brass plate into the epoxy. I will wax the thread so it doesn't stick to the epoxy and can be unscrewed when the epoxy has cured fully.

I believe that, providing the machine screw is the right length then there will be sufficient epoxy thickness above the end of the thread to seal the hole.

I supercub's case I think that someone in the past may have drilled too far, but not realized it, then replaced the plate and machine screw. This would more or less prevent water getting in so adequate, but not perfect.
 
Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Epoxy by itself is very weak. Are you using this as a structural support for this brass plate? In a FRP (fiber reinforced plastic) the strength comes from the fibers and the epoxy just holds it together. Bonding in the plate is a good proposal but use some glass cloth to provide the strength you will likely need.
 
Jul 24, 2020
12
Catalina Capri 16.5 Bass River
Thank you for your feed back. Yes I understand the need for fiber reinforcement. Generally I use WEST system, however because I will be working from underneath the boat I am a little concerned that unthickened epoxy will be too viscous and will tend to sag but thickened epoxy will lose strength.
My thinking is that there are two issues to resolve 1) to seal up the hole at the top end to prevent water getting up into the stub keel and from there to the bilge 2) providing strength to hold the machine screw and plate in position.
At the moment I am considering doing this in two steps. Firstly use a two part epoxy putty or maybe JB Weld because it is more of a paste than unthickened WEST System and force this up into the top of the hole. This should provide a good seal against ingress of water. Secondly to carefully drill up a distance slightly greater than the length of the machine screw and open it up a little and then paste layers of glass by painting on mildly thickened resin to hold the threaded plate in place. Finally it will be necessary to place something over the surface to squeeze it all up and prevent the epoxy from slumping out. As I understand it JB Weld has a strength of around 5,000 psi while WEST has a strength of around 7,000 psi unthickened. Since the JB Weld is there to form a water barrier up above the end of the machine screw it doesn't need so much strength.
What do you think of this approach?
 
Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Use saran wrap to hold the epoxy in place with duct tape or painters tape to hold the edges of the saran wrap. The epoxy won't stick to the saran wrap so it will just peel off after the epoxy cures. I can't comment further on your application as I'm not familiar with the application.
 
Aug 11, 2011
857
O'day 30 313 Georgetown MD
Better yet, go around the yard and find a few pieces of the shrink wrap that gets left around. Much sturdier and as its coated the epoxy won't stick to it as it cures.
 
Jul 24, 2020
12
Catalina Capri 16.5 Bass River
The epoxy is not really the problem, that's pretty straight forward. The issue is water coming through the srcew hole and how to embed a thread into the epoxy. The discussion is about shoal draft centerboard leaks. I am experimenting with knurled nuts and washers on a machine screw and bonded with JB Weld which I will later set into the fiberglass stub keel. The machine screw has been waxed so it will not bond.
Neither Saran wrap or shrink wrap have the rigidity necessary to stop the epoxy slumping as this is being filled from below. Slumping leads to voids and lack of strength.
For this I will clamp up a piece of ply that has been wrapped in brown packing tape and sprayed with release agent.
 
Sep 24, 2018
2,549
O'Day 25 Chicago
On my 25 the holes for the centerboard plate lead right inside the keel. I discovered this when fuel leaked into the bilge and then into the bilge through an unsealed hole (left by a PO). The CB was removed at the time and the fuel dripped right though and on to the ground. Perhaps someone used too long of a screw in the past or that's just how it is

I've used good quality painters and autobody tape as well as gorilla tape for keeping resin in place. The autobody tape is my go to. I spend a good 30 seconds pressing down on it afterwards to ensure a decent seal. Do use a filler as it will add strength and help keep the resin in place. I would get it really thick, place a piece of tape over the hole, push a syringe through the tape, inject and then cover up the hole with a second piece of tape. I've filled in deck holes that go all the way through with little to no leakage in the cabin. I assume after filling the hole, you'll be re-tapping it. Use 4000 or 4200 to seal the screw. Between the new threads and the 4200 you should be in a good place. Stronger sealant may lead to stripped bolts next time
 
Sep 24, 2018
2,549
O'Day 25 Chicago
I put 4200 on the threads of the bolt and for safe measure, on the mating surface of the plate. In the four or so years that I've owned this boat, I have yet to read of any reports of materials damaged by water inside the keel. Most of us that have done more serious work on it discovered a crumbling, cement like material inside.
Water freezing is another story however. I would recommend drilling a hole in the keel to allow any residual water to drain if stored in freezing temps. I found a very small amount of water inside before I started doing heated storage. It's pretty easy to reseal a 1/4" hole in the spring
 
Jul 24, 2020
12
Catalina Capri 16.5 Bass River
I certainly get freezing temperatures here on Cape Cod during the winter. I hadn't known until now that water would collect inside the keel so I will need to pay attention to that. Thank you for that tip.
Since water ran out when I removed the retaining machine screws would it make sense to just remove two of those when the boat goes up on the stands in the fall? Either support the c/b or even drop it right out maybe?
 
Sep 24, 2018
2,549
O'Day 25 Chicago
It took -30F weather for a week or two to cause damage to my keel

Removing one or more CB bolts would work if the forward end of the keel is lower than the aft end. I'm sure there's some room for water to expand but I don't know how much. I don't recall anyone else besides me having keel damage due to freezing water. I had some deck leaks that funneled water to the bilge and down into the keel through that unsealed hole. The boat was not covered in winter when I bought it

Drilling a drain hole takes about 30 seconds. Mixing resin, hardener and filling the hole probably would take 20-60 minutes including prep and cleanup. Add another 15 to sand flat when hardened if needed. Put some tape over the hole while it's curing. It'll hold the resin in place and minimize sanding
 
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