Mystery Leak

[RickK]

Don't want to be the soggy towel (sorry) in the gang, but I had a similiar problem, yet not as severe.  I would go out for the day and when I pulled the lower plug, would get maybe 2 quarts of water out. I checked everywhere and couldn't see anything boldly sticking out.  When I sanded down the bottom to refinish it, I found that the previous owner have run aground on something like an oyster bar and gouged the bottom (keel) deeply (to exposed glass strands) - yet had filled it with paint and covered it fairly well.  I repaired the bottom in that and a few other areas of dinks and such and now after a full day, I might get a tablespoon if any at all.
Like previously recommended, sand the bottom as a last resort but at least give her a thorough look along the keel.

[JimCt]

Ladies & Gentlemen....

We have a WINNER!

From the enchanting island of pearly sand and azure seas where we'd all like to be and through the ethereal magic of the world wide web, the winner is...

(drumroll)....

Bluesbrother!!!      


His answer was right on the mark!.  Have to admit when I first read his entry I thought, "a leak coming through an internal delamination??? Not a chance in h---!"  Well, he was right and I was wrong to doubt him.  

His prize (another drumroll) is the key to the ignition and a fully stocked cooler of beer (of his choice) on ice and fishing anytime he wants.  Granted, the fish up here might not quite measure up to what he's used to, but let that pass... I'm sure he'd find porgy, skate wings & bluefish to his liking after he got used to them, possibly.

So, what's next?  Well, looks like I've got to get a lifting ring and pull the Merc. off and see what's what.  With the engine off I'll see also about the deck scuppers; see if they need new thru-thimbles.  Regarding the leak itself and assuming the transom isn't shot, how should I proceed to fix the internal delamination?

Again, for a long distance, sight unseen diagnosis of the leak, Bluesbrother nailed it!

[Bluesbrother]

Exellent Jim,
I am glad you found it Eventhough the upcoming repair won't be all that fun, it should be better than sanding the entire bottom. By the way I will come pick up those keys and cooler as I will be in NYC with my family the first week of august!
Anyway greetings from the island with the pearly white beaches etc etc etc and a little too much intl press coverage lately...
Good luck with the repair...
Rudy.
Ps: just kidding about the keys...

[JimCt]

Well, I wasn't kidding.  At least I can take you for a romp around the waters here for a tour.  Maybe best to forget the fish.

The Repair.

Please review & let me know if I'm off base here... My belief (read "hope") is that the transom is fine with the only area of concern being at the very bottom where the scupper thimbles & lower motor bolt holes are.  That being the situation, in that area I plan removing a section of transom glass on the outside to expose the plywood.  My guess is that probably the bottom 3" to 5" of wood is delaminated.  If true, I'll skillsaw a line across the transom through known good wood and remove the skin & lower section of the ply down to the deadrise.  From there I'll cut new marine plywood to match the old & install it with West epoxy & dowels.  Then I'll lay-up a new skin with glass plys & resin.  That's it.

The transom, aside from the leak, is rock solid.  When I bought the boat this spring I did a thorough test by bouncing hard on the up-tilted motor.  Up & down, back & forth & all around.  No flex. None.  That's what leads me to think this repair maybe more in the line of nipping a problem in the bud.  We'll see.

[JimCt]

Just posted more pix of my 170 in Gallery.

[Bluesbrother]

Well, the way you describe it is exactly what I did with mine. Make sure you let the plywood once you have the transom open dry out well. Otherwise it will keep on working after the repair, also the epox might not get max adhesive to the marine ply. To get a real nice cut I have seen people use a router,  you need the right blade though.    Then comes the glassing, the sanding, the filling, the sanding, the painting, the sanding, the rebuilding and then...... the fishing!!!!!!!    
Rudy.

[JimCt]

Since the boatable season here is so short (as compared to, let's say, Aruba), I may put off getting into this operation 'till fall.  Good summer weekends are gold to me. If I get into this and find myself in a bigger project than planned, POOF!, there goes the summer.  Figure if I open her up late fall and give the structure 5 months to dry I'll have a better shot at good adhesion.

[Bluesbrother]

Jim,
A temporary quick fix to avoid problem getting bigger, you might try the following: If you can get to the effected area you could try to drill some holes in the effected area (just through the fiber skin) if you have enough play you could try to use a large seringe to inject some epoxy resin in the voids.(don't force the space as this will make it worse) start in the lower holes and work your way up. When a past hole starts to leak resin tape it off with ductape. Knocking softly on the skin will make the resin disperse as well. Remember this is only a temporary thing. I have done this in the past with an old angler I had, sanded downn the holes and painted it white. Lasted long enough for me to use the boat and pick my time to fix it.
Rudy. 8)

[JimCt]

Good idea.  Will give it a try.
Use thickened epoxy?

[Bluesbrother]

Don't make it to thick since you want it to run in all the voids....

[pbailey]

JimCt

You might want to try this product:

http://www.rotdoctor.com/

They have an epoxy product that has the viscosity of diesel fuel. (CPES)

Check out the specs and see what you think.

We're using this product in our transom, inspection of our transom shows only damp wood, no rot.  

pbailey

[JimCt]

Checked out rotdoctor.com.  Sounds like the right product.  The info. on their site is good too, especially with regard to storage ventilation.  Most boats up here are shrink wrapped for the winter.  Basically what they've created is a greenhouse... interesting.  Thanks for the lead!

To get to the transom area in question, engine's got to come off.  I have a front loader so lifting it isn't a problem.  Will pick up one of those lifting rings I see on eBay for Mercs.  I'd rather not lay the engine on it's side after it's off so I'll have to build a stand for it.  Once all that's done I'll get some pictures of the transom so you'll see what I see.

Something keeps nagging my mind about this whole thing: the motor clamp covers the two scupper thimbles on the outside of the transom.  By that I mean the clamp isn't just hiding them, the clamp is on them.  Deck water will drain out, but slowly. I'm wondering if this has a connection with the leak.  Looking at the thimbles from inside the boat, they're both sticking out a tad further than I'd expect.  Maybe that's how they came from production. Maybe not.  If the motor clamp has displaced the thimbles, even slightly, it makes sense the seal around them could be broken.  If one of you sometime could take a close up picture of how the inboard thimble ends, if they are as original, appear on your boat it might prove/disprove my hunch.  I'll post pictures of what I'm seeing here.

That's about it from this end.

[pbailey]

We have a 19'6" and the brass drain fittings are very tight to the transom.  It could be that the wood over time has become soft at these fittings allowing the compression of the transom from the cranking down of motor mounts making the problem worse. I will get some pic's for you.

pbailey

[JimCt]

Sounds good.  It'll be interesting to see your pictures.

[JimCt]

Ok, I've posted a picture of the protruding drain thimble in my photo gallery.  It's a tad hard to see but the rolled end of the brass is displaced outward about .100" from the plane of the transom.  That, I'm guessing was caused by the motor clamp pressing the thimble in from the outside.  And that, I'm also guessing, may also be the cause of my little problem here.

The goop you see around the rolled end was applied by some ass (me) trying to stop the leak.  
Didn't work.