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Zonker

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Zonker last won the day on November 27

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About Zonker

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  • Birthday 04/17/1966

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  1. If fewer and fewer US households own guns (only 35%), and the trend continues... Won't there be a point when the US population decides to change the gun laws due to popular demand?
  2. No. PVC structural foams are fine. Polyester eats Styrofoam like SJB showed. Epoxy does not. I suspect Vinylester eats but do not know.
  3. Like a BMW Auto transmission "sealed for life" Ever see the inside of an electric drill? The exterior is whatever crazy shape the designer feels will appeal to the consumer, the inside has a recess for the cylindrical electric motor. You cast or mold the bits that hold the motor in place at the same time as the cover. Zero added cost of machining.
  4. Having a friend teach you is great but learning in a dinghy course would also be very helpful in developing skills and reflexes that help with a bigger boat. A C&C 25 is a lovely boat. Maybe have your friend along for the first few excursions: you + friend + 3 scouts max (just due to lack of room for more) I'm sure your Scouts will love the boat (I was a Cub Scout leader for 3 years and Venturer leader (14-17 yrs old) for several years as well. When you are dealing with kids keeping them alive is a good idea so: - everybody wears PFDs unless it is stinking hot and no wind
  5. If the foam was that thick I'd just tape over the edge with 3 or 4" wide glass tape. But nothing wrong with wood. If you want to get fancy you rout out the core ~1/2 the depth of the wood so the wood sticks out of the glass a bit. Or take the foam core, glue wood strips around the edges, then cover the panel with glass. Lots of ways to do it. For the outboard cover - the gap is what matters. Think of noise like water leaking out. Put a gasket on the edge so it makes a good seal with whatever and it will be quiet. Have a 1/4" gap and it will be much noisier. Also - make the box
  6. I am pleasantly surprised that my WAG of 0.20 for the cylinder + hemisphere was about correct, as was the the tapered body. I didn't look them up! OK I agree about the tapered prop hub. But even the one they use is just a frustrum. It's like you gave your kid a CAD program. Yeah, it's not quite towing a bucket. But why wouldn't you even look at an outboard motor lower hub unit. Their nose fairing ain't no hemisphere.
  7. The pink stuff is OK if you don't consider them very structural. The shear strength of that type of foam is quite low. (about 1/4-1/5 of a PVC boat building type foam).
  8. The Cd of something like a laminar flow sort of thing like my sketch is like 0.05. A cylinder + a hemisphere is probably 0.2 or so. Say diameter = 75mm (3"). Draggy cylinder at 6 knots? F = 1/2 rho Cd A V^2 = 0.5 (1025 kg/m3) 0.2 (pi x .075^2 / 4) * 3 m/s = 1.3 kg so about 1 kg more than a streamlined body. Now 1 kg doesn't sound like much - but that's about 1% of the drag of a 30' boat at 6 knots. Why give that up?
  9. You're supposed to wait for slack tide?? Now you tell me.
  10. Butt with thickened resin is totally fine. The joint will be stronger than the foam.
  11. For locker partitions that somebody is not leaning against, you can get away with a single layer of 300 gm/m2 each side. For settee backs that might be bigger or heavily loaded by sails, big drunk sailors falling on them, then I would go with 2 layers x 300 0/90 or +/-45 each side. No CSM needed. Hmm good question. I'd say no problem if you put some weights on the top surface until the resin cures. I generally use epoxy so shrinkage is less of an issue. ++ 1 big panel and then cut pieces out of it. Laminating lots of little bits is very fiddly and the unfinished
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