Soft Spot in Floor...Structural?

[skydiveD30571]

Hi all, I found a soft spot in the floor of my boat (sig line) last night. It is way up front in bow, right where everyone hops into the boat from the dock. This is a 2007 and the floor is all fiberglass, no holes or cracks, with snap in carpet. I'm having a hard time believing there is any way a fiberglass floor like this could rot. Since everyone jumps in the boat right there, I'm wondering if this is a structural thing. Maybe the fiberglass underneath is cracking or giving? I'm not sure how to investigate this since it is so far forward that the ski locker doesn't go that far, but it is behing the anchor locker. I've never noticed it before, and it gives a noticeable amount. Not sure if continued use is going to put a hole in the floor or what!

 

[Woodonglass]

Re: Soft Spot in Floor...Structural?

That is a bit perplexing on a 6 year old boat. Are you the OO? Is she covered/Garaged all the time? How big of a span are we talking about? Pics always help us to SEE what you are seeing.

 

[greenbush future]

Re: Soft Spot in Floor...Structural?

My guess is the fiberglass floor you see is wood cored with fiberglass covering it. And that can rot out just like a wood floor w/o glass covering it. If moisture is under the floor it can rot out from underneath, then work it's way up. You will most likely need to gain access to what's up underneath, either through the ski locker or other access locations. Eventually you will need to cut the floor out in this area or the whole thing depending on how bad the rot is. I guess it could be just a fracture in that one location, but my bet is on rotting wood under the glass. It also raises other concerns about the stringers and transom regarding rot. All of these areas should be inspected as you evaluate what's up with your soft spot. The only way to do that is by taking core samples with a drill, then inspect the wood shavings for moisture and discolored, decomposing wood. Drill low on the stringers and transom, because that's where rot starts. Was the boat stored outside? covered/uncovered?

 

[jigngrub]

Re: Soft Spot in Floor...Structural?

How heavy are the hoppers that hop into your boat?

One of the worst things about fiberglass boats is no below deck access without having to fire up a saw or maybe a drill.

If there was no other access I'd drill a 1" hole in the center of the soft spot to see what I could see. If there wasn't any rot and it was hollow I'd order some 2 part expanding urethane foam and pour it to fill the void and support the soft spot.

 

[skydiveD30571]

Re: Soft Spot in Floor...Structural?

I will get pictures as soon as possible. Problem is there's not much to look at. It's a circular area about 6" in diameter, basically in the center of the bow area (forward of the windshield). Floor is all molded together with the structure that supports the bow seats (1 big piece) so if it is wood rot underneath, I have no idea how it got under there. I tried accessing the area last night but it is closed off...ski locker doesn't go that far forward.

I am the second owner, bought in june 2011. It is covered in the winter, stored outdoors bow-high with a snap-on cover during the summer. Every once in awhile I forgot to put the support pole under there, but I don't think I've forgotten it this year. Boat is used a lot (tomorrow will be the 20th time this season). I do all my own maintenance and cleaning, so I'm up front quite a bit and never noticed it until last night. If it's rot, it sure came out of nowhere. I was thinking of drilling in and taking a sample right there. What do I fill the hole with after I do so?

 

[skydiveD30571]

Re: Soft Spot in Floor...Structural?

How heavy are the hoppers that hop into your boat?

One of the worst things about fiberglass boats is no below deck access without having to fire up a saw or maybe a drill.

If there was no other access I'd drill a 1" hole in the center of the soft spot to see what I could see. If there wasn't any rot and it was hollow I'd order some 2 part expanding urethane foam and pour it to fill the void and support the soft spot.

Most of us are big. Of the 5 or 6 usual guests, 4 of us are 230lbs (an athletic 230lbs :wink

Thanks for the tips. It is underneath the snap in carpet, so the hole repair doesn't have to be extremely pretty as long as it holds up. I'll look into the 2-part urethane foam. I've never seen the insides of a boat, nor do I have any idea how they are made so it might be an interesting project.

 

[jigngrub]

Re: Soft Spot in Floor...Structural?

You can fill the hole with this stuff:

Bondo 272 Bondo-Glass - 1 Quart: Automotive : Walmart.com

I'm not sure that your deck is rotten, but it could be. I am pretty sure that there's a void under there though and the majority of boat designs nowadays depend on urethane foam to support decking instead of a decent framing system.

Let us know what you find if you decide to drill the hole. If there's plywood under there and the shavings come out wet, you have water intrusion problems.

 

[skydiveD30571]

Re: Soft Spot in Floor...Structural?

I'm sure I'll get a drill into it soon since the season here is basically done. I'm praying for a simple support problem and not wet wood (obviously) but we will see. So in the case of no wet wood, urethane foam to fill the void and bondo-glass to fill the hole? I've used that glass before so I'm a little familiar with it.

 

[Woodonglass]

Re: Soft Spot in Floor...Structural?

When you take the pic, don't get to close. We need a perspective of the bow area. How much "Deflection" in the deck would you say there is" 1/4"...1/2"???