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Repairing holes in ballast tank
Posted: Mon Aug 06, 2018 5:38 am
by Jwnj
https://drive.google.com/file/d/1ziToSh ... p=drivesdk
So i found something really interesting that would explain why my bilge takes on water, not sure who was so brilliant but clearly they didnt have enough wire to run around the ballast tank or did not know the tank rises all way to the floor. There are 2 holes ( 1 on each side) and they are about 7mm which is definitely enough to take on a significant amount of water when filling and later on.
After rerouting the wires what would you guys suggest, im assuming it needs to be water and air tight for the vent to work properly. Not sure about actual fiberglass patch vs some sort of round plastic plug with epoxy or adhesive would be enough.
Thanks for any input
Re: Repairing holes in ballast tank
Posted: Mon Aug 06, 2018 3:33 pm
by Highlander
West System G/flex 650 toughtened epoxy
J
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 6:36 am
by Jwnj
Thanks ill look for it locally, so you would just use that without any backing or plug?
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 6:55 am
by Jimmyt
Hard to find good help these days. Who put that pesky balance tank where those wires needed to go? Right when you think you’ve seen everything...
That’s a pretty dangerous mistake. You’re lucky to have caught it before it caused you serious trouble! Basically, you were emptying your ballast into the bilge. Yikes
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 9:47 am
by Russ
At least the PO didn't drill through the hull and run the wires outside.
You must have had a LOT of water in there.
Could have been worse
--Russ
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 10:09 am
by Divecoz
Lots of options.. you could buy a couple of rubber or silicon plugs from the local hardware store 7mm or 9/32" and, a small 3oz tube of 3m 5200 fast cure and be done with this issue pretty dang quick.. provided you can reach the hole which I assume you can.. OR you could put a big dab of 5200 FC on a piece of duct tape and slap that over the hole.. tape just to position the big dab of 5200 where you want it..
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 1:10 pm
by Jwnj
Thanks for the tips. My next worry is there are 4 screws for bilge pump and switch under the removable cargo box under seat going into floor. They seem really small and i assume epoxy or something was used to affix them not just drilled through. Should i be worried about those as in removing to check or if i dont see them coming out the bottom should be ok? I think people are used to 2" hulls on powerboats when they install things and they assume a bilge should be wet so it doesnt matter since you have pumps.
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 3:10 pm
by sailboatmike
I have used aqua epoxy putty too great effect for jobs like this.
I would countersink the holes first to give greater sealing and adhesive area before filling though.
Best thing is this stuff works even if the area is a bit damp.
Here is a youtube clip giving some info.
https://www.youtube.com/watch?v=_kenw2_ckVk
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 3:38 pm
by BOAT
Jimmyt wrote:Hard to find good help these days. Who put that pesky balance tank where those wires needed to go? Right when you think you’ve seen everything...
That’s a pretty dangerous mistake. You’re lucky to have caught it before it caused you serious trouble! Basically, you were emptying your ballast into the bilge. Yikes
Uh, not to mention electricity in the ballast tank??? Anyone want an electrified ballast tank?

I guess that would keep the critters out of the ballast water.
Re: Repairing holes in ballast tank
Posted: Tue Aug 07, 2018 6:07 pm
by rsvpasap
Splash Zone. It's magical.
https://tinyurl.com/yd58sphb
Don't forget the gloves.
https://tinyurl.com/ybdwn4ea
I had a persistent but mysterious leak into the bilge that only happened when sailing or in rough weather at the dock. Turns out water was splashing up and in where the base of the mast support pole attaches to the top of the swing keel hull enclosure (under the dinette table). My boat lives in the water and I've now had a totally dry bilge all spring and summer. Life is good.
Re: Repairing holes in ballast tank
Posted: Wed Aug 08, 2018 5:33 am
by Jwnj
So in your opinion the 4 screws for the pump i should leave alone or replace with epoxy? No idea how thick the hull is in that spot.
Re: Repairing holes in ballast tank
Posted: Wed Aug 08, 2018 5:57 am
by Jimmyt
If it were mine, I'd remove them and repair the damage with epoxy, or fiberglass; depending on what I found... I glued my bilge pump to the hull, but you could epoxy some blocks in if you want to screw your pump in. I just don't feel like driving screws into the hull is a good idea - especially if you're not sure whether they go through or not.
I assume you're talking about a wood screw or sheet metal screw and not a properly bedded through-hull install of some type - which isn't likely for what you're talking about. It's probably fine if it's watertight, but I just don't like it.
Re: Repairing holes in ballast tank
Posted: Wed Aug 08, 2018 6:57 am
by Nauti Nell
I see people using wooden blocks to mount things to here a lot. Sometimes treated, sometimes not. I would/do/and have used the plastic/composite boards for odds and ends that I might need to mount something to.
or
Flex tape...as seen on TV....
Re: Repairing holes in ballast tank
Posted: Wed Aug 08, 2018 7:38 am
by Tomfoolery
Just thinking out loud here, but if the holes were about 7 ft apart, and if you heeled the boat all the way over til the mast was at the water, then the water depth would be 7 ft, and the pressure on the bottom hole would only be about 3 psi. If it's a 1/2" dia. hole, then that would be about 0.15 pounds of force on that plug, or about 2-1/2 ounces. I wouldn't think it would take much to seal a hole that size against that little pressure, so any decent epoxy repair, or glassing on a block to mount things on, should be pretty easy to do. Or so it looks from way over here.

Re: Repairing holes in ballast tank
Posted: Wed Aug 08, 2018 8:28 am
by Jimmyt
i was suggesting adding mounting blocks to the hull if Jwnj wanted to reattach his bilge pump to the hull with screws. Nauti Nell's suggestion to use synthetic blocks is right on. This was regarding his second question about whether to remove the bilge pump screws from the hull and repair the hull injuries. Apparently, the PO screwed the bilge pump directly into the hull glass.
I completely agree that blocks or reinforcement of any kind is probably unnecessary for the small ballast tank hole repairs - as long as the holes are prepp'd and clean when the goo goes in.
I get confused sometimes at these forks in the rabbit hole...