VL,
She is a Dog for sure. Not here to crush any dreams though.
You have a serious cancer growing there, and more so on the metal side than probably your crown fiber glas side.
To correctly repair it, a professional would need to be sectioning it out and replacing the rot if they were worth their salt.
You could poor boy a repair yes. Would you be a menace to society driving it down the road? That could be a subjective call, depending on the person making it.
Would it be a long term patch. No, You got Rot that needs addressing.
As far as the "Seaworthiness" of your Titanic II anything is doable, but the skill set here to do it right you need carpentry and auto body Repair skills.
I bet your leaks /seeps will be massive along that belt line where the sections meet trying to attempt a poor boy repair.
** I am looking at that pic where you have the 4 screws circled. Is that Rust the top of the van edge where the crown mates up? if so , definitely not good, just shows the level of rot in the metal.
What do the floor pans of the van look like, Rusted too? Hope not.
In tact exterior Paint remaining is probably your biggest supporter of holding back water from seeping in at this point.
You are going to have twist and some flex traveling and banging down the road. Flex, Twist along with Rot is not a good combo.
Without real repair Skills you should not dig in deep and remove that crown. You will be regretting that as you are hauling Old 78 Betsy off to the Junk Yard.
Patching is your only real hope and that is equivalent to buying a pill on TV that says you can lose 30 pounds in 30 days. Yea…It is possible I guess with amputation.
For most of us, this type of repair, it would be in the “Kids, Don’t try this at home" category type.
Being a realist, anything other than cutting away the rot is just polishing the turd and you are faking a repair.
I am not here to knock your vision. Anything is possible if you throw some cash at it, or have the DIY skill set to pull it off.
I just don’t want to be legally liable where I can be quoted on the forum telling you there is no worries either of your crown flying off killing the motorcyclist behind you.
Naaw Just joking…
That Fiber Glass wont break off. The Metal on the van, well not so sure….?
Just don’t drive over 70 MPH.
Realistically, the metal on the van where the crown mates to what was original Roof, Belt line, that is the weak link not the fiberglas, although the Glas does needs touched up a bit?
As for bonding new glas.
First of all the surfaces should be ground, cleaned, or sandblasted or wire wheel on a rotary tool, air blown clean before any bonding should be attempted.
Usually when you are bonding glas you want the pieces to lay flat, not have a crinkled edge and your rotten portion is just that Crinkled.
The section of glas you lay, your goal is to roll or press out the air out of the mat fibers with the resin tight like applying a band aid to your skin.
You can see much of that fiber roof shows its long term durability just by looking at it.
This severely rotten section you can't bond new glass to brittle destroyed section of rusty Van, clean or grinded sand blasted metal yes. Rusty metal no. If you took a grinder after that metal it would dissapear as dust.
If somebody told me John, your going to war with this old dog and I had to fix it and go camping, I would attempt to fish plate it. Meaning the Horizontal line where the crown meets original van roof, bond to a good structure on both the metal and glas sides, which will be nearly impossible.
No matter what you do, your going have this problem if you slam gunk in that gap of rot and create a blob of a gooey repair, by fish plating and patching by putting a huge band aind around the inside belly…
You go out the drive way and you hit a bump and you get flex, crack and there is your new leak, or pocket that retains water furthering the rot.
John