Mystery Leak
 

I just purchased a 85 Monark modified v hull Jon boat (fishing set up) it has a 20 hp evinrude and. 40lb thrust foot controlled thruster

So here is my problem- keeping in mind that I replaced the drain plug already with a T type expandable rubber (and will be putting in a float switch for the bilge this weekend)

The boat is sitting on a mooring on the lake and after sitting during the night when I go out to it in the morning about 8am and switch the bilge it runs for about 4-5 seconds. When I then go out there about 7-8pm I switch the bilge on and it is running for about 30 seconds?

I am obviously leaking, previous owner never moored it as he day fished multiple lakes, not being swamped and have a new Basspro cover on it
I am off the belief that the rocking of the wakes during the day and causing pressure somewhere while attached to the mooring? While trolling or just drifting no water at all. I am thinking the rocking and back and forth tug on the mooring is creating sucking around the drain plug?
(my larger pleasure boat gets water in the same way but not to this extent or does it and it just does not seem it because of the size?

There are no dents in the hull, no cracks that I can see as I also filled it up with water and did not see anything before launching it. I have read about the drain plug tube being misshaped over time? Also there is marine epoxy on the stern from where something used to sit and that did not see to be leaking when filling the boat before launch. The forward live we'll is also dry so I do not believe it is coming there as I also have the drain tube straight up to prevent backwash from the drain
noticed also that my rear live well wont drain also not filling up unless pump turned on, and I think that is supposed to go into the bilge so I don't think its coming in through the live wells

I am thinking of putting some gasoline grade rubber line and clamping it around the drain tube and putting a ball value on it, and if it will fit, the drain plug on the outside to see if this is the problem, other than that there would have to be a crack somewhere
Help me out please

Is this happening every day?

I have a bass boat that on days with heavy wave action will take on more water while at the dock- either spray over the bow or around the low transom. However on calmer days the bilge stays dry.

everyday seems like. I excluded Sunday and Monday and a little of Tuesday out because of the weather, but yesterday it was beautiful and this was the case, also it was on Saturday, the first day it was in the water

Can I assume your boat is aluminum as has rivets?? If so the most likely culprit is loose rivets. Not uncommon is this type of boat.

The reason it's not leaking when your in it is because you have increased the pressure on the hull and the aluminum cross members thereby sealing it better. When it's just sitting, there is no inward pressure on the hull and water is getting in around a couple loose rivets as the hull expands and contracts with heat. Aluminum has a LOT of thermal movement.

For a temporary and quick fix, seal over the rivets with a high quality silicone from the outside. You don't need much. For a permanent repair, replace the loose rivets.

Good Luck!

P.S., if your boat is not aluminum disregard everything above! :)

Dan

thank you for the idea, it is aluminum and it is a welded hull, but there are some rivets I holding the bracing for the floor (floor supports are aluminum and built with the boat) I don't believe seeing any below the waterline except the stern, think I will pull it and do it,

any others?

See if you move the drain plug tube. They can loosen or become misshapen to cause a leak.

Captain Tolley's leak-sealer should work at the drain plug tube (and loose rivets), but will interfere in getting a good weld should heli-arcing be necessary.

http://www.frost.co.uk/media/catalog...eys_cure_1.jpg

Where can I pick that up
West marine maybe?

West Marine has it for $15.
http://www.westmarine.com/buy/captai...t-2-oz--243990

Is there a thicker clear epoxy by any chance

Hey what about that stuff on TV where the guy seals up a screen door on the bottom of his Jon boat.... Bet that would work.... It must work, it's on TV!! :)

Dan

And I just read this on the internet so it must be real :laugh::laugh:

If you can, pull the boat out of the water on a trailer. When on dry land, put some water in the boat. Give it a little time, and look underneath to see where the water is leaking from.

My neighbors have been great they have been watching it twice a day for me

here is the update:
another day yesterday and this morning:
nothing yesterday am (less than 3 second pump when last pumped about 8pm prior) then yesterday at about 6pm pumped about 25 seconds, this morning less than a 5 second pump


When I bought the boat after test driving and purchasing I brought it home, let it dry, and then filled the bilge with water, it sat overnight - nothing

just went to west marine on my break and picked up Capt. Tolleys. Spoke to an old salt in there as well, He was saying the same thing, the heat in the day could be causing the aluminum to expand and contract and allowing water to seep in. Said this should fix the problem. Also I am going to check and more than likely just replace my live well pump line as that could have a small crack in it, but I doubt it, because any crack in a line or hull would show a continuous amount of water in the boat when checking at 12 hour intervals, but you never know if it is rocking back and forth during the day on the water line

yanked it on Friday evening, let drain, got underneath it, found most of the rivets dripping, also pulled the floor and found that someone used 2inch plant foam (like the stuff that you poke the stems in and retains water) was used as ballast foam. Must have removed water wait of close to 60lbs, and I ended up replacing that with 2 inch closed cell water and mold resistant foam insulation found at any home depot type stores. coated all exposed rivets from the inside and even the ones under the fishing decks, went underneath and did the same thing. Let sit for over 24 hours launch it fished for 4 hours, put it on the mooring, waited over 9 hours......still taking in water but only pumped for about 20 seconds.

used capt. tolleys from the top, and then also lifelock on the bottom

Think I will pull it and have someone weld the rivets, would that be a problem? I would not think so

hi guys
Have any of you heard about/used Gulvit?
seems it is a bottom coat like item

"Great-Stuff", Home Depot's expanding foam (from a can) isn't the best choice for marine applications, as it absorbs standing water—but used where it mostly stays dry—it should be OK. The "good" stuff comes as a two-part mix, and it is even messier to work with in tight quarters.

"Welding" (heliarcing) requires an extremely clean surface. Now that the rivets have goo on them, your best choice now is to hammer each rivet—using a second hammer to back up each rivet—this requires two persons. Both will find ear protection a must. :eek2:

It still won't be leak-free, but you'll have brought the rivets into closer tolerances than before, and it won't have cost a lot of money.

:look: