Monark mystery leak

[AC2717]

Hi new to the forum after lurking for a little bit, as I just purchased a 85 Monark modified v hull Jon boat it has a 20 hp evinrude and. 40lb thrust foot controlled thruster ( a little underpowered but gets the job done and keeps me under regulations and rules though)

So here is my problem- keeping in mind that I replaced the drain plug already and will be putting in a float switch for the bilge this weekend

The boat is sitting on a mooring on lake winnipesaukee NH and 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
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.

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 here is marine expoxy 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

Help me out please

 

[KMixson]

How high are the wakes during the day? Are there a lot of boats going by during the day? If you can't find the leak I would fill it at least to the waterline with water and let it sit for a couple of hours or even overnight then check for leaks.

 

[AC2717]

definitely not swamping the boat, also mooring cover on it.

I am wondering if the back and fourth is allowing suction around the drain plug and when it is sitting obviously no suction there for no seaping

I am thinking about pulling it again and letting it sit
The other thing I am thinking about is clamping some gas line around the drain tube and putting a ball valve in and then putting the plug on the outside if it will fit in

 

[keelme]

put water in your boat and see where it leaks out

 

[WaterWaif]

The bilge drain and live well both get water in my sea nymph. Inch and a half in the live well maybe and a pint or so in hull average. I suspect it gets siphoned in when motating or runs in when deaccelerating..No gates or valves on it that I know of like a scupper.

 

[rscottp]

Could one of your buddies be pranking you? Dumping a couple gallons in when he goes by just to drive you crazy.

 

[WaterWaif]

Well now, just pulled livewell pump to check impeller after blowing the fuse today,(pump is froze up) and the water line fitting at pump is broken. Silicone looks like a former owner found it too. L.o.l.. That explains my water in the bilge a lot better. #-o

 

[AC2717]

rscottp » 31 Jul 2014, 20:27[/url]"]Could one of your buddies be pranking you? Dumping a couple gallons in when he goes by just to drive you crazy.

ha-ha wish that was the case, my neighbors have actually watching it twice a day this week because I had to come back to work this week to pay the bills lol

 

[AC2717]

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 boat 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

it was mentioned to me that the aluminum could be expanding during the day in the sun loosing/widening the rivet holes the few that are on this (most are on the stern) and the water could be seeping in that way???

 

[AC2717]

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
__________________

 

[lckstckn2smknbrls]

You need the seal all the rivets and seams with Gulvit.

 

[AC2717]

thank you for the Gulvit post
this seems like a bottom coating type material, it shouldn't add too much weight I would think?
good idea to just coat the whole bottom?

 

[lckstckn2smknbrls]

AC2717 » Tue Aug 05, 2014 1:34 pm[/url]"]thank you for the Gulvit post
this seems like a bottom coating type material, it shouldn't add too much weight I would think?
good idea to just coat the whole bottom?

It goes on the inside of the boat. There's no benefit to doing more then the seams and rivets.