fallguy
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The Boat Design & Boatbuilding Site
Thermo-Lite Boards
- Thread starter Quattro64
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Thermo-Lite boards, if used throughout, could build the boat 30%-50% lighter. So I think the boat 'could' be built to 'spec' but still be significantly lighter. I just don't know what that would mean regarding a safe cat, capsizing etc...??
comfisherman
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Honest question.
Why not just have a design roughed out for the material you want? Cost of design relative to even a small pile of core is cheap.
Why not just have a design roughed out for the material you want? Cost of design relative to even a small pile of core is cheap.
fallguy
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At some point, we establish you are grasping at air. I mean this politely.
The decision to change cores is not arbitrary.
If a design calls for 26 pound foam core for the transom; you don’t get to decide 13 pound is okay.
The most common direction for builders to go is the other way. A designer specifies the boat and you add a solar panel. Or your fillets are a bit bigger than he’d build. Or you decide another 3 gallons of water would be nice.
I’m done commenting here.
I'll probably stick to the designers plans, I am just curious, In my research it is shearing strength that is important in a ply-epoxy-glass build. Which these boards, edge out ply by a little bit. Ply is way stronger at tensile strength. So stronger and lighter, more thermal and sound insulation, don't need epoxy? I'm just a curious guy that wants to build the best boat. These things ARE used in boats in place of ply??
You should either select better information sources or make sure you understand the basic concepts beforehand.
Epoxy isn't going to let damp air in and rot the ply, that's in the same tales category as "wood breathing". Every foam that's used as a structural core in boat building is closed cell and doesn't absorb water like a sponge, regardless of its chemistry.
Using a high density foam like Thermo-Lite for the entire hull is only necessary for special cases, and a cruising sailboat isn't one. You could legitimately use it in a few places, but that would be maybe a few square feet for the entire boat.
If you don't like or trust plywood and epoxy just buy plans designed for foam. Do yourself a favor, compare the price and weight of regular boatbuilding foam (PVC, SAN, PET) to this stuff. If you want to compare apples to apples you need to compare the weight and cost of the entire layup, from outside paint to inside paint, but that's only possible if the design already has several build options. Otherwise you can only look at similar size and displacement boats, but the designers don't necessarily have the same priorities, so at times the results can be somewhat strange.
One thing to keep in mind is that the golden age of big plywood builds has passed. Not because plywood was found to be an inferior material but because cost has increased and closed the gap to other materials even for the amateur builder.
Here's a reality check: you can find perfectly fine 50 year old boats made from polyester-balsa, polyester-PVC foam, epoxy-plywood, epoxy-wood, and some other techniques that aren't in use anymore. At the same time you can find 10 year old boats of the same construction that are basically shot because they were improperly buildt or maintained.
Epoxy isn't going to let damp air in and rot the ply, that's in the same tales category as "wood breathing". Every foam that's used as a structural core in boat building is closed cell and doesn't absorb water like a sponge, regardless of its chemistry.
Using a high density foam like Thermo-Lite for the entire hull is only necessary for special cases, and a cruising sailboat isn't one. You could legitimately use it in a few places, but that would be maybe a few square feet for the entire boat.
If you don't like or trust plywood and epoxy just buy plans designed for foam. Do yourself a favor, compare the price and weight of regular boatbuilding foam (PVC, SAN, PET) to this stuff. If you want to compare apples to apples you need to compare the weight and cost of the entire layup, from outside paint to inside paint, but that's only possible if the design already has several build options. Otherwise you can only look at similar size and displacement boats, but the designers don't necessarily have the same priorities, so at times the results can be somewhat strange.
One thing to keep in mind is that the golden age of big plywood builds has passed. Not because plywood was found to be an inferior material but because cost has increased and closed the gap to other materials even for the amateur builder.
Here's a reality check: you can find perfectly fine 50 year old boats made from polyester-balsa, polyester-PVC foam, epoxy-plywood, epoxy-wood, and some other techniques that aren't in use anymore. At the same time you can find 10 year old boats of the same construction that are basically shot because they were improperly buildt or maintained.
comfisherman
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Amen, preach!
Wish folks were as wed to methods as they are materials.
Wish folks were as wed to methods as they are materials.
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When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
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