1957 20 ft dyer

nickyp

Captain
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Nov 3, 2012
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bermuda
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20ft dyer
haven't clocked it yet.
about 10 knots wide open.
i can hear cavitation when running. my 14x14 prop is as big as i can fit, and its quite close to the hull. i will also think about fairing or scalloping the back of the keel in order to get cleaner water.

its very stable and comfortable.
turns on a dime

001.jpg
 

scallywag

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Oct 19, 2011
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maryland
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25'general marine
Very Salty looking boat , should raise some attention out on the water. Nice job.
 

Hurdy Gurdy

Lieutenant Commander
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Sep 30, 2011
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BERMUDA!
Yes Nick! Good to see you hear man.Looking forward to some raftups this summer! See ya at the creek!
 

nickyp

Captain
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Nov 3, 2012
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Location
bermuda
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20ft dyer
Some pics from today

Hauled up to put on a new zinc
The old one fizzled away
Thought I'd post dome pics of the running gear

image.jpg
 

nickyp

Captain
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Nov 3, 2012
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Location
bermuda
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20ft dyer
Prop clearance is a bit small.
About 1 3/8" on a 14" prop
I wonder how much it affects running.
I do hear a gurgling from the hull at mid rpms
Does anyone think scalloping the backside of the keel will make any difference?
 

Keelboater

Admiral
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Clinton Harbor
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35' Bruno & Stillman
Nicky - What is the angle of the prop shaft to the waterline? I have read that 15 degrees is the absolute max for obtaining smooth running gear. This is a great looking boat. Not many of them around!
 

nickyp

Captain
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Nov 3, 2012
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bermuda
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20ft dyer
Thanks

I haven't measured the angle but I know it's obviously pretty severe.
Not a very efficient setup at all really:
Losing through the v drive transmission
Losing from the steep angle
Losing from not being able to swing a big enough prop
:(

If I were to do that project over, I would consider losing the v drive, and centrally mounting the engine, and fabricating a tunnel to accomodate a big enough prop.
Oh well.
It's still a very manouverable and comfortable boat. I just think when your only working with 20hps, you may as well get the most out of it.
 

Keelboater

Admiral
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35' Bruno & Stillman
Nicky - The reason why the shaft angle may be the root of your early cavitation problem is this: On very steep shaft angle installations, the blades of the prop begin to see different running conditions. The blade that is moving upward is actually moving away from the water flow while the blade moving downward is moving into it. That creates variable loading on the blades and can cause vibration as well as cavitation early on. Granted this is no high HP application, but in theory it's all the same. Also, the steep shaft angle tends to push the hull above the center of gravity which results in a bow down attitude that is less efficient. But no matter how you slice it, that is one cool little ride you have there.
 

nickyp

Captain
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Nov 3, 2012
Posts
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Location
bermuda
Boat Make
20ft dyer
Thanks again.
I know my boat is inefficient, and it's good to know why that may be the case.
This is why I am a member of this forum.
Appreciate the insight
 
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