1970s winday day cruise foam core deck

[Beardmode]

Hello my fellow boaters,
I have been noticing sagging when walking on the upper deck of my boat. I finally decided it is time to recore the boat and have some fiberglass fun. However, when cutting open an inspection hole i find that there is roughly a half inch of solid foam. My question is. How can I repair the stiffness of this deck and can I use epoxy or will it nelt the foam. The foam is dry and seems to have delaminated from the upper skin so I am wondering if epoxy injection may be the best option.
Thanks

 

[Scott Danforth]

Recore with foam

I would use poly vs epoxy

Epoxy won't melt the foam. It's just 3x the cost

 

[Beardmode]

Recore with foam

I would use poly vs epoxy

Epoxy won't melt the foam. It's just 3x the cost

This foam seems to be sprayed in foam. Would you suggest replacing with the sheets of foam they sell nowadays?

 

[Scott Danforth]

This foam seems to be sprayed in foam. Would you suggest replacing with the sheets of foam they sell nowadays?

It's not sprayed in if it's laminated. It was core foam put in the mold then covered on (layer on the inside)

 

[Beardmode]

It's not sprayed in if it's laminated. It was core foam put in the mold then covered on (layer on the inside)

What do you think about removing the top layer in 1 or 2 pieces. Laying down some resin and then re applying the original glass?

 

[Scott Danforth]

That would be more work than removing the top layer, removing the damaged core, gluing in new core, then 3 layers of 1708 vacuum bagged

 

[kcassells]

Put up some pictures.

 

[Grub54891]

If at all possible, some decks are screwed down. I prefer to remove and do the work from the bottom side. Thats if it's screwed down. Hope it is for you!

 

[Scott Danforth]

being a sailboat, while there is a bit less fairing and you may not have to redo the non-skid on the foredeck working upside down underneath...... however, its messy and a PITA.

much easier to re-roll the non-skid from the top while working in shorts vs having to try and hold up 3 yards of resin soaked 1708 while trying to get the glass in place and its falling on your head

there are some good threads on recoring a sailboat over at boatdesign.net and a few of the sailboat forums

 

[Beardmode]

Here sre more pictures. Sorry for the confussion it isnt a sailboat.

The core does not seem to be damaged nor is it wet. (In the small inspection cut) the area that saged the most seems to be dry and structurally undamaged. At this point I think the upper skin sinply delaminated from the foam core. I will be cutting off a large section of the skin to further investigate and will post more pictures.

 

[Beardmode]

Here sre more pictures. Sorry for the confussion it isnt a sailboat.

The core does not seem to be damaged nor is it wet. (In the small inspection cut) the area that saged the most seems to be dry and structurally undamaged. At this point I think the upper skin sinply delaminated from the foam core. I will be cutting off a large section of the skin to further investigate and will post more pictures.

 

[Scott Danforth]

The main reason for delamination is too low a density of foam (based on many threads on boat design).

The foam starts to break down due to loading

If the top layer is delaminated, you need to remove the whole outer skin.

I would also take a core sample (about 1" in diameter) to see if the other side of the core is still bonded

That will determine the next steps

 

[Beardmode]

Not sire if you guys can help out but I keep getting a failure when attempting to upload a picture. This is the pop up i get.

"The upload failed because the file could not be written to the server. The site administrator will need to resolve this before any files can be uploaded."

 

[Scott Danforth]

We are experiencing issues. Including us mods.

The wizards that control the site have been notified

 

[Beardmode]

We are experiencing issues. Including us mods.

The wizards that control the site have been notified

Thanks for info! It looks like it may be fixed. Here is a video and few extra picutres showing the progress. The foam was still adhered to the bottom layey. I have decided that because I am this far I really do not want to have to do this twice. I am replacing the core with m80 perforated foam. Adding a layer of two of 1708 to to top sode of the bottom skin. I haven't decided yet whether I will reuse the top skin or not. Any cons to reuseing the top layer?

Thank you very much

 

[Grub54891]

I prefer to use the top layer as it’s already made to fit and helps keep the original look. if you have to re-do the edges of the cut you can just blend it in like a non skid 1-2” wide strip around it.

 

[Beardmode]

Still cant post update pics howwver this is the profress so far..
Bottom layer has been sanded a 1.5oz stitched csm has been epoxied down as well as a layer of 1708 biaxial fiberglass. Next is thickened epoxy and new perforated foam corecell install. After that I will be laying up one more layer of 1708 and gluing down the original top skin down in 1 step. Let me know your thoughts