Soft Spot on Bottom of Boat?

The boat I plan on buying- 1961 fiberglass Arkansas Traveler 15' Skijack has a spot (4" in diameter) on the bottom of the boat about 2 feet in from the transom on the flat part of the boat that has small spider veins in the paint. As a result, when I push on it, it feels a little soft compared to the rest of the bottom of the boat. My question is- how does fiberglass get soft like this? and what needs to be done to repair it?
I planned on painting the entire boat if that helps.
Also, if I plan on repainting the boat can I remove the old drain hole and replace it with a new one (and use some epoxy to treat the wood before I put a new one back in) just as a preventative measure since I will be putting all this work into the boat anyway. The transom is very solid- it doesn't rock or move at all and I drilled a couple test holes already to check it. I just don't want to put all kinds of money in the boat and have an eventual small leak by an old drain plug?
Make sense??
Thanks

Re: Soft Spot on Bottom of Boat?

Do a search here on Test Holes, Bore Holes...... your boat needs further investigation (below the deck).

Re: Soft Spot on Bottom of Boat?

has a spot (4" in diameter) on the bottom of the boat about 2 feet in from the transom on the flat part of the boat

Click to expand...

It sounds like you are referring to soft spot on the HULL of the boat that when you push on it from the outside, it is soft?

If this is the case, proceed with caution. The most likely cause (99%) is moisture has delaminated the glass (1% previous repair?). It will only get worse unless it is repaired. If you can't see any obvious signs of intrusion from the outside of the hull, then the problem is from the inside... and that means more problems.

Good luck!

Re: Soft Spot on Bottom of Boat?

Its most likely impact damage from hitting something, its soft because the glass is fractured under the gel coat. There's no way to tell how bad it is unless you can look at it from the inside, or start grinding on it from the outside. Can you get to it from the inside?

Re: Soft Spot on Bottom of Boat?

If it is a 3" X 3" area how much should I grind out- all of it? Some of it?

I won't be starting this project for a few weeks but I want to get all my ducks in line before I get started.

Thanks

Re: Soft Spot on Bottom of Boat?

You won't know until you start grinding, white lines, or areas that are white are the fractures, they need to be removed. You need to go a few inches past the bad area and taper the edges, but don't grind all the way through the hull. Leave a very thin layer of glass so you'll have a shape to lay glass on.

Re: Soft Spot on Bottom of Boat?

So I should grind from the inside of the boat and leave a thin layer of glass and paint- got it! What type of blade on the grinder do you use for this type of work (to remove the fiberglass deck and to cut out the soft area)?

I am beginning to realize that this is going to be a pretty big project! I am excited for the day that I will start it though. This is probably going to be the only boat I ever own so I want to do it right the first time (The wife thinks I'm getting it for free from the neighbor).
This is probably the only way that I would have gotten a boat because she would never approve paying a couple thousand for a boat.

Little does she know the work that is going to go into it. It will be cool though when it is done- even she thinks so with our young kids who love the water.