Is foam enough?

[1975VikingDeckBoat]

I started cutting things out of my deck boat. I expected to replace the transom, stringers, and floor. But to my surprise it looks like my boat doesn’t have the traditional stringers like I’ve seen in a ton of YouTube videos. It’s got two pieces of plywood glassed together attached to the floor setting on foam. Can someone shed some light on this subject?

 

[cup of Joe]

Wow that reminds me of my 1989 Reinell, It had all the wood rotten, It was a bad year for reinell's
The stringers, transom, motor mounts, all rotten wood.
A sawsall and grinder were my tools, and a painter suit duck taped around my wrist and ankles , gloves full face mask.
And make sure you have a woman's Nylon stockings , You laugh? well as odd as it sounds the Nylon stockings were used to pull fiberglass dust off your skin. Rub the nylon with the direction of your hair on your arms,legs face, to pull fiberglass off.
I had no choice but to remove the foam it was all mildewed.
I had no place near my home to reinstall the foam so I Built bulkheads like the titanic. .
But my bulkheads were built from bottom to deck not halve way like titanic. Right or wrong it was done.
that boat was sturdy as a rock.

 

[CrazyFinn]

I started cutting things out of my deck boat. I expected to replace the transom, stringers, and floor. But to my surprise it looks like my boat doesn’t have the traditional stringers like I’ve seen in a ton of YouTube videos. It’s got two pieces of plywood glassed together attached to the floor setting on foam. Can someone shed some light on this subject?

Interesting construction - looks to me like the rounded channels/humps in the hull provide the structure and rigidity. Does it look like that from the bottom side as well, or is there a foam "core" or something in those humps?

 

[1975VikingDeckBoat]

After cutting more of the floor out today looks like it has three bulkheads that hold up another of the small stringers in the center. The foam is solid as a rock I’m 300 pounds and it doesn’t even flex with me on it. The rounded humps feel hollow back towards the transom I haven’t felt them up further because of the foam. I can’t tell if the bulkheads are glasses to hull or not yet. This is just a fishing boat so I’m trying to do things as cheap as possible so I’m curious if the foam isn’t water logged would I have to replace all of it?

 

[1975VikingDeckBoat]

[No message]

 

[Scott Danforth]

Most likely 4# foam, could be 8#.

 

[1975VikingDeckBoat]

I was thinking 4lb do you think I should just replace it the same way it was?

 

[Scott Danforth]

I would. the foam is structural, with a good sole in the boat, and a fully foam filled cavity, the boat will be solid, and it will float if you forget the plug