Light coming through

[Costy]

So I got below in 21' Mcgregor and I am seeing light coming through the front lower V shape part of the boat right about the area where the boat can be rammed on the beach. I looked on the out side and the paint/gelcoat is scratched and I can see the fiberglas and that is exactly where the light is coming through.
How thick do you think the fibergalss is there and do I need to be concerned?
Once the boat is stable on the trailer I will fill with water to see if I have any leaks in tha area and also around the bolt that holds the keel in place where I see lots of thick rust.
The boat had about 3" of water inside when I purchased and the last owner told me that the water is from the washing the boat and also from the rain (no much rain in So Cal) I do believe him but I am about 2 months out of finding out.

Thanks Costy
Ps. As I am writing this I am thinking that I should have saved some of the water before I drained and ran it in the Ph metter @ work and see if it was salt water

 

[caguy]

If the fiber glass is intact, you just need to refill gelcoat. The fiberglass is translucent and lets the light through. Your water us likely coming from the keel lock down bolt. With all of this rain we just got you would find more water in the bilge than there was before, and/or evidence of water elsewhere, ie sole cushions or runs on lining.
A ph meter measures acidity, will it tell you if it is salt? Try a few drops of Silver nitrate. If I remember my chemistry you will get a white precipitate of Silver chloride, AgCl. Even if it is rain water it will still be salty from earlier salt water in the bilge. When it evaporates it leaves the salt which will be reconstituted by rain water.

 

[MrBill_FLL]

pics?

probably not an issue, seal the decks and paint the boat.

then go sailing.

 

[Merlin Clark]

I would not fill it with water. Water weighs 62 lbs per cubic foot and will destroy your hull. too much weight and either it will push the bunk supports up thru the bottom or split the halves (port and starboard).
Others have taped up all the gaps and pressurized the hull with air. Probably could use a large shop vac and a sprayer with dish soap and water, spray the suspect areas and watch for bubbles.
It doesn't have to be much pressure, just more than outside the sealed up hull.

 

[oreana123]

I've laid in a lot of bilges over the years, installing accessories and wiring boats. I've seen this in other sailboat hulls where gelcoat has been removed and the sun shines on the hull.

True story: motoring on Lake Pend O'reille one very dark night, I ran into a pinnacle of rock, which stopped the boat from 6 knots. Dead stop! I hit exactly on the laid up portion on the leading edge of the hull. Boat was as heavily laden as it ever gets- 4 people and camping gear for a week. Needless to say, no part of the crew was happy with this turn of events. I quickly inspected the bilge and even hung over the bow railing with a light, no apparent damage. Next day I swam around to look at the hull: just a scratch on the gelcoat. Lesson learned (besides not trusting a depth meter whose sensor is in the AFT bilge) is that this is a very strong layup on the very leading edge.

 

[rsims111]

caguy and oreana123 are absolutely right. These boats are a lot tougher than we give them credit for. My Mac 26M got broadsided about 4 ft back from the starboard bow by a 14 ft aluminum fishing boat going almost full speed with a 9.9 HP outboard (don't ask - fools will be fools). I too could see light coming through when I looked under the V-berth, in fact it was a surprising amount of light. Full examination of the hull revealed that the only damage was a 3/8" (or less) diameter chip out of the gel coat. When I did the gel coat patch all traces of light disappeared.