Project - Scull boat

I know this might open a can of worms and dont want to get off topic but this was why I went with vinyl ester on the Broadbill and am using my over ordered material on this boat: (cost vs water absorption vs bonding vs strength)
1. Polyester Resin
• Advantages:
o Lowest cost – most affordable option, ideal for large projects.
o Fast curing – speeds up production and repairs.
o Good UV resistance – holds up well in sunlight.
o Easy to use – forgiving for beginners, sands and finishes easily.
o Bonds well to gelcoat – common in hull and deck construction.
• Disadvantages:
o Weakest adhesion – poor bonding compared to epoxy or vinyl ester.
o More brittle – prone to cracking under stress.
o Water absorption – can lead to blistering and delamination over time.
o Short shelf life – degrades quickly in storage.
o Toxic catalyst required – requires careful handling.
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2. Vinyl Ester Resin
• Advantages:
o Superior water resistance – excellent against blistering and osmosis.
o Better elongation – more flexible, resists cracking under stress.
o Good chemical and heat resistance – ideal for high-performance boats.
o Stronger adhesion – bonds better than polyester.
o Middle price point – cheaper than epoxy but stronger than polyester.
• Disadvantages:
o Short shelf life – degrades quickly like polyester.
o Not as strong as epoxy – though stronger than polyester.
o More expensive than polyester – adds cost to large builds.
o Catalyst required – precise mixing needed for proper curing.
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3. Epoxy Resin
• Advantages:
o Strongest adhesion and bonding – sticks to wood, metal, cured laminates, and composites.
o Excellent waterproofing – minimal water absorption, prevents delamination.
o High flexibility – resists cracking under stress or impact.
o Best chemical resistance – resists fuels, solvents, and corrosion.
o Low shrinkage – maintains shape and strength after curing.
• Disadvantages:
o Highest cost – significantly more expensive than polyester or vinyl ester.
o Longer cure time – requires patience and controlled conditions.
o Limited compatibility – does not bond well to polyester-based structures.
o More complex mixing – requires precise ratios and careful handling.
 
What’s the correct way to fix this. It doesn’t extend past what you see. What you can’t see is that the 2 sides of the crack are offset and I couldn’t align by just pushing and pulling IMG_2169.jpeg
 
Here are some pics.
I have more pics, but this shows the bung hole and motor mount
 

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one thing about foam is if water gets in there the pourable will absorb water. I’ve seen on other forums people advocate for the foam board since future repair will be easier. We redid a buddy’s aluminum boat. We filled the spaces with frp wall board on the bottom across the ribs(front to back). So the pourable foam didn’t t touch the hull on the bottom.

I also think if you just sealed the floor with inspection holes would be just as good or better. Technically air tight and if somehow water did get in you could sponge it out and or air it out to dry.

Tony
 
David, thanks for the photo. What is the white insert. Looks like pvc pipe. Also any idea on the size?

Tony, I think Im leaning toward wallboard foam. Not sure I’m good enough with glass to do a air tight pocket
 
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