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Hull water leak (sinking)

DGA

DGA

Active Member
We hauled Island Girl out for the season last Tuesday. So stayed on her overnight on the night before. Early that evening before, I noticed the auto bilge pump run. Then 10 minutes later, it ran again. And again. I opened the floor hatch above the pump, this is the long one aft of the fuel tank access hatch. I saw some moisture from under the fuel tank, top of the keel, figured this was remaining shower water drainage. Then found the source of the water, on the starboard side about 10" below the depth transponder. Water was coming out from a small delaminated area of the hull fiberglass. I do not think this is damage or stress, just the edge of one glass layer that didn't lay down completely. The water is not coming from the transponder directly, so I am thinking it is making it's way through the glass.

I have not had a chance to remove the transponder yet, but it has some white sealer on the outside that is now falling apart. I would think this should be an O ring seal, so suspect some dodgy work by the last owner, and probably an old, hard or cut O ring. Any insight into this?

Dave.
 
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Oh, didn't know that they are owner installed. I don't have a pic, sorry. Both speed and depth are under that floor hatch. Knowing now that they are owner installed, I am guessing just bored through the hull fiberglass, with no bonded inserts, so the O ring is on the raw glass, and the sealer was sealing up some area of non compacted fiber. If I were installing those I would use a G10 tube and bond it in. Now I will have to somehow remove all the sealant so I can vacuum infuse the area with epoxy. All good to know.
These two instruments were never wired up, so this is a recently introduced problem.
 
My speed and depth are forward of the keel, in access outside the head. There should be a fiberglass backing plate installed to strengthen the area. Mine doesn't have an additional tube. But the through hull for it (which is plastic) has a flange on the outside. I'm not sure if there is a gasket, or if 5200 was used. I know it came with a gasket, but I had a yard install it.

How does depth work if it isn't facing down? Anyway, if these instruments aren't hooked up and you are hauling for the season, I would remove them, patch the holes, and consider a different location. Depth should face down, and speed should be in front of the keel out of any disturbances.
 
They are facing down, at an angle of course. Installed just above the keel 'wall', on a more horizontal part of the hull, in that access hatch area. They had never been connected to the existing Raymarine ST60 instruments on the fairly new binnacle. I got them working this season and they are a great addition. Well, the water speed quit working a few months ago, after the haul out I found small fresh water shell fish of some sort had decided to live in there and jammed the water wheel from moving.
 

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The paddlewheels are usually removable form the inside, with a plug to replace them with. They clog quickly, and you should remove them when not in use. A bit of water will get in the boat when you swap it for the plug, but not to much and it is all in the bilge.
 
Sounds like a scary, for the novice sailor, plug to install, but a good tip, thanks. I'll try to find the plug, but not sure I have seen anything like that in the assortment of 'spares' that were in the boat.

So likely then, there is a plastic or nylon through hull that this transponder is installed in, so it would be leaking outside that and going into a void in the fiberglass.
 
I tried to find some pictures, but these days all there are, are youTube videos. If they are recent and not fairly old, speed transducers for most brands are all made by Airmar and should look similar. If it's old, it might look different but should still basically work the same way.
 
Good video, the water coming in wasn't as bad as I had imagined. Mine is that same Airmar I think. I'll find or buy a new plug for next year, and seal up the leak when I go back to winterize the boat in a few weeks.
 
Well, back onboard to winterize Island Girl. I think I figured out where the water leak was coming in, attached pic shows a mangled O ring alongside the speed transducer. I will still remove the two through hulls and reseal them though, hopefully can get them out without breaking them. Interesting to find the speed one has a little flap to reduce ( or stop?) the incoming water when you pull it for cleaning.
 

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Use marine debond to slowly remove the 5200 (or similar) adhesive used to seal in the through hull. Also get a bottle of isopropyl alcohol to neutralize afterwards and take care of any runs. I put a dam made out of a rag about 2-3" outside the through hull to minimize drops going into the bilge.

I just removed 3 old transponder through hulls from previous owners (wires were cut to all of them). It took a couple of days to dissolve the adhesive, but all of them came out cleanly. Be patient and trust that it is working - is the only thing I could find that would do it without riding damage to the fiberglass.

Here's a new video on it from the company:
 

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Well this was an alarming find. I had time this afternoon to remove the depth transponder through hull, a ton of Sikaflex and silicone to dig through and I was actually able to push it out of the hull from the inside. The silicone sealing washer was on the inside, not where it should be at all, but it wasn't the cause of the leak. It had a square piece of plywood on the inside of the hull, for reasons I soon found out. I dug at what I expected was epoxy inside around the plywood and it was Sikaflex as well, so put a pry bar through the hole and pushed, and the plywood came away from the hull fiberglass. So the hole in the hull was the same diameter as the head of the through hull fitting which is why it was mostly flush outside. So all that was keeping this Morgan from quickly going to the bottom was the Sikaflex bond between the hull and the plywood!
 

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To make this right I machined a piece of tooling board and made a mould to make a one piece depth sounder mount. It will bond directly to the hull using Hysol 9430 structural adhesive, eliminating the plastic through hull and seal joint, the 3" boss protruding from the bottom will fill in the large hole in the hull and make it flush. While I was at it I gave it a 15 degree angle to get the transponder vertical. I insulated the carbon from the aluminum threaded insert in the layup. The transponder O rings seal directly on the tooled carbon surface.
 

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Completed repair/ modification. The 15 degree angle was correct, and the transponder inner corner is flush with the hull surface. Going in the water tomorrow and I feel a lot better about this now.
 

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