Hole in Bilge to Stringer and Foam Void

[SirDuke716]

Hello,

I'm currently having my transom rebuilt on a 1976 Galaxy Fiberglass Bowrider with a 115hp outboard. The boat was purchased new in 1976 by my grandfather, then gifted to my father in 1986, and now gifted to me in 2017. She's a beautiful boat that is stored inside 51 weeks a year, and only used 1 week a year in northern Canada fishing for Pike and Walleye....and some Skiing!!

The transom has rotted and is being replaced. The floor has been cut back 24" inches to inspect stringers and we noticed a drilled holes in the side of the bilge wall, near the bottom.

My question is the Bilge Sump has a 1/4" or 3/8" hole drilled close to the bottom on a side wall through to the void in the hull that is occupied by the foam and stringers. Is this normal? Is this hole intended to let water that is under the floor, trapped in the hull, an avenue to enter the bilge sump and be pumped out by the bilge pump?

It tells me then, that normal rain water that hits the top side of the floor, travels to the stern, and "waterfalls" into the bilge will now escape the bilge sump and enter the stringer and foam void of the hull and begin to fill that up, too. Whereas both the water in the hull, and bilge sump, must equalize to a height that triggers the float switch. That seems wrong, to me, hence why I'm asking for education.

But again, how would water that is trapped in the stringer and foam voids ever get out of the boat if there was not such a hole in the side of the bilge near the bottom of it.

Thank you for your education.

 

[savetexomabeaches]

Pics help a ton.. But I would assume that any hole drilled at the bottom of stringers was made to allow any water that got under there to flow to the back and out of the holes into the bilge.

 

[fhhuber]

Most likely there was an issue with water accumulation in the void/foam areas and the hole was made to let it out.

If the boat is mostly stored on a trailer with bow raised, then the hole is a good idea, because no matter what you do, there will be some water getting in those areas. If it can't get out it soaks the foam. A few hours water exposure followed by days (weeks... months) of storage on the trailer would et the water all escape or evaporate.

But if the drain plug hole clogs with leaves or other debris then it won't matter if the hole is there or not, your boat will fill with rainwater and rot.

 

[SirDuke716]

1st Picture = Here is a birds eye view picture. The transom is out, the floor is cut back, and what is left of the bilge sump can be seen (square footprint between stringers). The hole in the bilge sump would be to the starboard side of the boat. If you look real close, you can still see the hole in what is left of the vertical wall

2nd = Picture = The bilge sump has not been cut down, yet, in this picture. The hole is on the starboard side, near the bottom on the vertical wall.

The boat will be stored in a dry rack, unless I'm using it for the day. For 1-week a year the boat will float at dock during our fishing trip.

On the surface, it makes sense to me that should water enter the hull area, it needs a way to escape, so the hole in the bilge sump is there to allow that. On the flip-side, when normal rain water enters the bilge sump, it is allowed to now enter the hull. That is the scenario that makes me scratch my head. Almost like it needs a one-way valve

 

[savetexomabeaches]

looks like a drain hole, and a lot of fun work

 

[ondarvr]

Pay no attention to what the original hole was for, it didn't need to make sense then either, things like that were just done with little forethought. You should rebuild it as needed with better techniques, but you're trusting somebody else to do that, which all too frequently doesn't turn out well.

 

[SirDuke716]

Pay no attention to what the original hole was for, it didn't need to make sense then either, things like that were just done with little forethought. You should rebuild it as needed with better techniques, but you're trusting somebody else to do that, which all too frequently doesn't turn out well.

Would your suggestion be then, to not put a hole in the newly rebuilt bilge sump to allow the trapped water in the hull a place to go?

 

[ondarvr]

You do whatever the new design calls for. If it were me, the stringers would be hollow and I'd make sure water could flow freely to a point where it could be pumped out, and the foam would be suspended off the hull and sprayed into a plastic bag so it would be less likely to come into contact with water. Foam, wood and water all in the same compartment don't make for a good outcome.

 

[kcassells]

In the perfect boat world no water is supposed to get under deck. phewww!

 

[fhhuber]

We don't live in a perfect world.

Every submarine in the US Navy leaks. The nuclear subs survive being underwater for up to 4 months at a time by pumping out the water that leaks in.

A perfect sub wouldn't leak even at test depth.

Watch companies got sued over the "Waterproof" label on watches which proved to not survive being used while scuba diving to 120 ft underwater. So now they are labeled "Water Resistant to XXX feet"

Your boat has a lot more ways it can leak than the sub or the watch. You will NEVER cure them all.