leaking riveted starcraft ('82 MR180)

[redneck joe]

ok kids - got the boat last year, new it had a leak, found 5 or 6 rivets that were leaking (mostly just a slow seep) so replaced those. Blind rivets with ample 4200. Found by putting a good amount of water in the thing with the plug in.

Still have my leak.

Never thought much about it as I have to bilge pump in so i just pump out occasionally. Might be just me but i think it might be a bit worse this second year. It must have been happening for a long time as there was silicone on some rivets and along some joints and some kind of paint underneath.



So had a great weather day last week and spent the afternoon on the water and did some standardized testing.


15 minute intervals for three different scenarios, run the bilge timing it:

on plane, approx 4000 rpm and 20 mph. pumped 12 seconds
hull / no wake speed, 18 seconds
floating in the wind, napping and dropping my beer, 29 seconds

It appears I have a backwards acting leak. I had someone tell me the rivets would not leak until moving / on water because if on trailer the water pressure would seal it but thinking no because i had the several weeping ones i fixed plus when moving way less water coming in.

What are the areas of the thing that would cause an at rest boat to take on that much water? I don't want to overload the (roller) trailer with too much water in the boat but sure would like to remedy. Not ready to replace the floor for several years so,.....


help

 

[Scott Danforth]

my guess is its on the keel seam or outer chine seam. leaking less as the boat is up on plane

 

[jbcurt00]

Where the bow diamond shaped plate meets the keel chine is also a good place to look. The bottom is 1 continuous sheet except for the split to make the bow curve.
How bad was transom, gunwale sidewalls & deck when ya got it?

Depending ^^^ Chine cracks are a good possibility too...

 

[redneck joe]

Transom is fine, everything LOOKS like original equipment including floors and vinyl, etc so was expecting a bad rivet or two but as I type this i started thinking would the material at the joints dry up if this was a barn find? Dude i bought it from got at an auction but in such good shape could have sat in a barn for years.

If so is that too far to fill up on the (roller) trailer? Could i use my floor jack to jack up one side to get the water over there? Waterline at the back goes up maybe 10".

If it was just the transom then on plane would be almost zero water inflow i would assume but that since it does it way more just sitting?

 

[redneck joe]

oh and all the livewell stuff on transom is sealed with plugs.

 

[Scott Danforth]

I wouldn't fill it.

If the livewell thru-hulls are plastic, they may be leaking.....even with plugs

 

[redneck joe]

ok well as we left to visit friends for supper out tonight, yes it is leaking. Not much but it is coming out of a weep hole in the keel. Didn't know they put weep holes in a keel? About 2/3rds the way of the the start of the bow curve.

 

[airshot]

Allows keel to drain, most all aluminum boats have keel drains. I know you dont want to remove the floor, but much better and safer than filling the hull !! Remove floor the take your boat out with some good paint markers and start marking leaks. Once marked you can check for cracks or leaky rivets. Rivets can be re bucked to stop them from leaking then after cleaning, coat all seams with gluvit on inside. Forget using any silicone sealers, no good on a boat. They also make hull paints/coatings that are thick and contain fibers to seal up cracks and rivets on the outside below water line.
You have many options, but the floor really needs to come out first !!

 

[rxl650]

I've messed with alot of small open tinners over the years, but with a floor, it makes it tough. I have not used gluvit, but I know many that have. We have a place on a semi private lake that is very shallow with rocks the size of mini vans everywhere. Some exposed, most are not. Everyone has cheap little tinners that have been beat to death. Even cheaper outboards. As mentioned above, Gluvit is quite popular. On the worst rivets I used sidewalk bolts,nyloc nuts, 4200 inside and out. The sidewalk bols have a low profile head. Not pretty, but when all else failed...Then built some removable floors so my wife wouldnt step on them. lol

 

[redneck joe]

well, if i've done my math right and iirc the new pump i put in was an 800 gph, that is over 6 gallons coming in during a 15 minute period and what little seepage I see coming form the keel hole that doesn't add up and i'll look over again but there was nothing under there that was glaringly obvious when i looked it over last year.

It does sound like it might be in the livewell holes due to the volume so to test that i could point the tongue tot he sky and use a bit of water to get to those levels?

 

[redneck joe]

gonna tell on myself. Not 100% sure yet i'm going to try to take her out tomorrow.

So when i brought her home there was a plug in each of the livewell holes. Took them out to inspect and on the (I believe) drain there was pipe tape on it. So of course I took it off and it wouldn't fit so i pulled a joe and wrapped back up as the 10 other 'normal' size ones didn't fit.

This morning as I tilted it nose to the sky I heard water hitting the driveway and was excited for a few seconds until I got back there and saw the hole was letting just a little bit out. Then it hit me.

The plug is gone. smfh. It was there - I always check the other two when i put in the hull drain.

I did not pull the plug on the way home, still has water, nothing else all day on the drive.

So my volumes and times all fit the pattern i had a drain hole, especially sitting as the boat would be level allowing the hose to empty into the hull.
at hull speed about the same but with less pressure maybe even a slight venturi effect. If it is the drain house, and disconnected at the livewell which I'm sure it has been) then it would be low enough in the hull to drain.

The on plane still has me wondering - the hole should be not taking on any water?

Anyway when I get new plugs in and test I'll update.

 

[Scott Danforth]

Remember, livewell pumps are rated at 0" of head. So if the rise from the pump to the discharge is 1 foot and you have 6 feet of hose (~1' of additional head) you have to look at the chart for the 2' of head. Which is closer to 600gph

 

[redneck joe]

thats a bunch of math....

 

[Scott Danforth]

thats a bunch of math....

Yes Joe, math and graphs

 

[rxl650]

Waters gettin deep round here. I'm in over my head. lol
I had a livewell that was taking in water everytime the drain dipped below the water line. I used it for storage so I disconnected the drain line, got distracted and forgot to plug it. After a short venture onto the bay I noticed the water in the boat and headed back to the trailer to deal with the hose. At this point I realized the hose did not have a upward facing loop that was causing positive preasure in the line to put water in the well. I hooked it back up with the loop and no more water. Possible you have a simular situation. Under power it would take in little to no water in comparison to waves dunking the outlet while sitting still. Can you even trace you lines and connections?

 

[redneck joe]

honestly cannot remember if I looked that deep when I got it. I removed the pump for it and (thought) I had all sealed up. Not sure livewell is removeable and a PO had it converted to an insulated cooler with a custom welded steel drop in for it - really nice. I cannot really access under the floor but do have a periscope camera somewhere around here I might could run into the line in and see if anything hooked up. I'm plugging the port regardless. I noticed today one of the plugged thru hulls is also plugged from the inside. Not sure why i'd have three lines to a livewell? One was PVV threaded nipple into the apparently threaded thru hull.

 

[Scott Danforth]

if its a single livewell, there will be a supply pump, and a drain

 

[airshot]

Mine has three hoses/ outlet/inlets what ever. Lowest outlet is a drain, then the top one is a fill hose from the pump. Then just below that, is the overflow. I don't use live wells so all are plugged off and the livewell is just storage.

 

[Scott Danforth]

something to think about

the last 3 plastic thru-hulls I had to replace was because the flange broke off.

plug would not help that situation

back to the leak. double check all the thru-hulls

then look at the rivets/seams

 

[redneck joe]

Yeah i think I'd have enough access to replace thru hulls without messing with the floor, but i went out and did some redneck testing on the lake today and think the plug will be 90% of it until i get to the thru hull replacement. Planning another day out early next week, plug here tomorrow so we'll see and I'll report back.

For the livewell, yes three lines. i pulled out the stainless tub and pull the blue board insulation. Drain, line in and overflow. Overflow is disconnected but since it doesnt get filled no worries but the drain is definitely not hooked up no thru hole there at all. I guess it would still be called that.

Good (short) day on the water, I'll put some pics in the nice pic thread in a bit.