Hole Drilled in Bilge Tank - By Design?

[Tony Walton]

Noticed a 1/4 or so hole in the bottom of my boat. It isn't caused by damage, it is a perfectly drilled hole. Its on the lower left side of the boat. Is this by design and if so, why?

 

[Blueone]

Noticed a 1/4 or so hole in the bottom of my boat. It isn't caused by damage, it is a perfectly drilled hole. Its on the lower left side of the boat. Is this by design and if so, why?

No holes are bad.... repair that

 

[MonacoMike]

I agree, there should be no hole located there. Did your wife just up the life insurance on you?

 

[Tony Walton]

Very odd...why the heck would someone drill a hole there? Just glad it isn't a gaping hole. Regardless, any recommendations on repairing it without having to do a bunch of body work or having to take it to a shop?

I've had positive results with JB Weld for many other repairs but have never tried it on a boat.

@MonacoMike...I'm going to have to check into that insurance policy!

 

[Stingrayaxe]

Vandalism? Never seen anything like that.

 

[Creekwood]

That is definitely a mistake hole or vandalism. Marine-Tex is not great structurally and will need a good bonding surface on the inside of the hull wider than the hole or it might pop out. I would make sure to sand down a spot on the inside of the hull down to the fiberglass maybe the size of a quarter to get the bilge paint off. Then make sure that the marine-tex covers that spot as well as the hole so you have a good bond. Level the outside as best as you can as well. It yellows a bit over time so if you don't like how it looks, you can buy gellcoat from Spectrum to match reasonable well and fix it better.

 

[dtfeld]

Definitely not supposed to be there.

To fix it right, I think you will need to grind back down to glass and fill it in with a thickened resin and some glass mixed in it. Then redo the gel coat. That might be a job for a pro...probably about same cost to have it repaired as buy all the supplies.

 

[Tony Walton]

Got looking a little closer and pushed a pick tool into the hole. I can't see it in the bilge are. Had someone move the tool around and it sounds like it is within the engine mount base in the engine compartment. Ironically, I looked at the other side again to see if there was another, and there is but not in the same spot. Same thing, does not show in engine compartment when I put a pick tool through it.

I know a guy that specializes in boat body work that I'll ask about repair. I'd rather leave it to a pro if I can afford to.

 

[Creekwood]

Got looking a little closer and pushed a pick tool into the hole. I can't see it in the bilge are. Had someone move the tool around and it sounds like it is within the engine mount base in the engine compartment. Ironically, I looked at the other side again to see if there was another, and there is but not in the same spot. Same thing, does not show in engine compartment when I put a pick tool through it.

I know a guy that specializes in boat body work that I'll ask about repair. I'd rather leave it to a pro if I can afford to.

If it is not accessible from the inside, then that is very weird and looks like someone did some vandalism to try to sink the boat. Those look like they are below the waterline when the boat is in the water.

 

[Tony Walton]

If it is not accessible from the inside, then that is very weird and looks like someone did some vandalism to try to sink the boat. Those look like they are below the waterline when the boat is in the water.

Yes, both are below the water line. So I suppose there may be a bunch of water inside the hull that is not accessible through the inside or outside of the boat?

 

[Creekwood]

Yes, both are below the water line. So I suppose there may be a bunch of water inside the hull that is not accessible through the inside or outside of the boat?

If it has been in the water and that area inside is not open to the bilge, then yes. There may be no way for that to drain. Some boats have sealed in compartments with flotation foam in them, and that may be what is in there. You don't want that filled with water.

 

[DWABoat]

Some questions:
How long have you owned the boat?
Is the hole recent? Have you washed or waxed the boat to know if the hole was created after you purchased it?
How deep is the hole? Is there wood inside the opening or only fiberglass resin?
Has there been any work done on the boat (trailer or boat) where it could have been drilled by mistake?
Bizarre, for sure.

 

[Tony Walton]

Some questions:
How long have you owned the boat?
Is the hole recent? Have you washed or waxed the boat to know if the hole was created after you purchased it?
How deep is the hole? Is there wood inside the opening or only fiberglass resin?
Has there been any work done on the boat (trailer or boat) where it could have been drilled by mistake?
Bizarre, for sure.

I’ve owned it for a year and bought it as a project. 1996 175 model. Last registered in 1998 so been off the water for 22 years. From what I can gather, it wasn’t winterized correctly, cracked the block so there it sat.

I’ve had it out one time since getting it running. That was this past weekend. I noticed the hole after I had it home and was washing it. The one hole actually has rust stains around it so I think it was there before I got it.

I can push a small pick into it to the handle, which is about 4”. I don’t see any wood inside the hole but it’s under 1/4” in size so hard to see much inside of either of the holes that I found.

I think it would have had to be drilled from the outside. It isn’t visible on the inside. Hard to think it was an accident. Trailer looks nearly new because it’s been sitting so doubt any work was done on it.

 

[DWABoat]

It’s like someone was trying to take a core sample of the hull or create a drain for accumulated water inside.

I don’t know if there should be foam injected in the core of the hull void or if there should be wood. If there is supposed to be wood, that may be some work for you.

Can you access the inner portion of the hull where that would be? It may be something to consider cutting a section out on the inside to inspect.That would be easier to repair since cosmetics are not a concern. Someone on this forum will be better to advise you than me at this point. I would not simply patch ad move on, if it were my boat. I will keep reading. Please keep us posted.

 

[Tony Walton]

It’s like someone was trying to take a core sample of the hull or create a drain for accumulated water inside.

I don’t know if there should be foam injected in the core of the hull void or if there should be wood. If there is supposed to be wood, that may be some work for you.

Can you access the inner portion of the hull where that would be? It may be something to consider cutting a section out on the inside to inspect.That would be easier to repair since cosmetics are not a concern. Someone on this forum will be better to advise you than me at this point. I would not simply patch ad move on, if it were my boat. I will keep reading. Please keep us posted.

I wondered about someone trying to drain water too. I think both would be accessible through the engine compartment. The left side hole goes into the motor mount pad and the one on the right is just forward of the trim pump assembly. Neither are seen on the inside.

Good idea of cutting the inside and having a look. I’m a little uneasy about patching it and not looking inside to see what I’m dealing with or how much water may be in it.

I’d like to know if it’s foam or wood inside and also like to know if/how much water is sitting in those voids.

 

[Tony Walton]

Did a little looking today. The hole on the right side appears to be from someone (before me) over drilling a hole to mount the battery tray. I blew air into the hole and absolutely no water came out, and it pressurized very quickly so suspect the area inside the void is likely not damaged.

the left side drained about 7 gallons of pretty clean water out. It appears to also be an over drill but may be under the gas tank or very near it. Initial air test shows nothing but going to blow air in it and bubble test with soap and water some more to see if I find anything.

I also talked to the previous owner. He said he kept it int the garage for the time he owned it and didn’t do any drilling and never saw water on his floor.

I talked with a couple different marina’s about the holes and potential damage in the voids. I was told by both that there is foam in the voids and that it doesn’t break down with water.

Short of cutting holes to inspect, hard to tell if there’s any damage. They recommended a sealer they use to plug the hole.

I think I’m going to temporarily seal the holes with RTV and get it on the water. I’ll pick that out once I get it off the water to see if any water comes out. If it does, I’d suspect a leak somewhere else. If it doesn’t, I have to evaluate if I want to cut a hole or just seal the holes and use it.

Here’s a few pics of the right side. The third pic shows how far the wire goes through.

 

[Soulshine]

Definitely weird but I’d skip the RTV as a temporary patch.

Silicone will prevent your permanent repair from adhering correctly.

 

[Tony Walton]

Sealed up the holes temporarily with a marine silicone. Had it out twice for 5-6 hours each time. Cleaned the sealer out of the hole and no water came out.

I really think the 7 gallons was from my first trip on the water. Doesn’t seem there is any water intrusion so permanent fix in the works.

Thanks all!