What's faster?
06-09-2002, 11:42 PM
#1
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What's faster?
For a lower unit finish, which is the fastest? Polished, gloss paint, or buffed primer? I kinda suspect the answer, but I want to hear what other people know (or think they know 
)
)
06-10-2002, 12:07 AM
#2
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I guess a slightly rough lower unit. Going on the same theory as the sanded hull bottoms.
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06-10-2002, 08:13 AM
#3
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In theory, a slightly rough surface is better for reduced drag.
A smooth finish will allow [mostly]uninterupted laminar flow and induce direct water-to-solid friction. A slightly sanded or rough surface will 'hold' or grip some degree or water, a microscopic boundary layer, and create water-to-water friction -- the latter being less.
A smooth finish will allow [mostly]uninterupted laminar flow and induce direct water-to-solid friction. A slightly sanded or rough surface will 'hold' or grip some degree or water, a microscopic boundary layer, and create water-to-water friction -- the latter being less.
06-10-2002, 08:50 AM
#4
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Yea, it was my understanding that the buffed primer was the fastest. The question is by how much?
06-10-2002, 10:37 AM
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So if you go with a slightly rough finish wouldn't you lose some prop efficiency ? You're introducing air to the prop/blade ?! I think it's going to be a very similar to nose coning a drive(you want to keep as much of an uninterrupted flow of water to the prop as you can) ?!
06-10-2002, 11:04 AM
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Actually, I believe the smooth polished surfaces are "sticky".
06-10-2002, 01:21 PM
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I think the differences would be so minor. Probably not even noticeable. Just like some prop shops will polish a prop and some won't both claim their way to be better ? Can they prove it ? Usually not. I think it's mostly just eye candy.
Now if you were going for a world record maybe a few tenths would be worth it.
On the nosecone issue, don't they usually want to smooth out the water before it gets to the prop ? With a rougher finish you'd be disturbing this water ? Which is correct ?!
Test is the only way and then it would have to be identical conditions(temps , water , fuel , weight etc.)
It's hard to say. I'm sure if you made calls to the manufacturers each would claim theirs to be faster ???
Now if you were going for a world record maybe a few tenths would be worth it.
On the nosecone issue, don't they usually want to smooth out the water before it gets to the prop ? With a rougher finish you'd be disturbing this water ? Which is correct ?!
Test is the only way and then it would have to be identical conditions(temps , water , fuel , weight etc.)
It's hard to say. I'm sure if you made calls to the manufacturers each would claim theirs to be faster ???
06-10-2002, 01:40 PM
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Play along Gary, because I'm thinking gloss black. 
