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Vincent DePillis

Member Since 19 Jan 2005
Offline Last Active Yesterday, 07:15 PM
*****

Posts I've Made

In Topic: Rope/knot/splice load testing

05 April 2014 - 05:00 PM

Can't we PLEASE get some one to test some 9mm Dux on thimbles and pins of different radii and profile?  

 

This is not an academic question for me.  When rerigging my F31 TRI with 9mm dux forestay and cap shrouds, I did not want to use the full 8/1thimbles at the jesus shackle, because of potential mast chafe.  I had some custom thimbles made which were a bit wider (to allow more flattening) at a 5/1 radius.  (Thank you Luke Burritt at Yachtfitters in Seattle). I stared at that Dux graph a bunch.    

 

I gotta say that the Dux graph looks way too smooth, and is presented with way too little technical background, to be very reassuring.  

 

Vince DePillis

(B.A. in History, Real Estate Attorney, with absolutely no engineering background at all, and never really got the hang of algebra.) 


In Topic: Perry Sliver Class Day Sailor

04 April 2014 - 10:11 PM

Sloop's Blakely Rock is tomorrow.  Follow the feet around?


In Topic: Rotating wing mast

18 February 2014 - 09:14 PM

Soma--

 

Obviously you are correct that resources in recreational sailing are limited.

 

But maybe the question is too general-- covers too many variables, like what kind of wing mast, compared to what kind of fixed rig, at what angle of sail.  I wonder if you could convince some of your sailing contacts to model a simplified 4 case scenario.  Ignore (i) weight, (ii) windage of stays, (iii) effect of jib.  Model 2 dimensions only.  Assume bolt rope for both.  Assume width of mast section is the same-- only difference is that one is D shaped, and fixed, and the other teardrop shaped and rotating.

 

The cases to be modeled would be close hauled (15 degrees off apparent wind?), and 90 degrees to apparent.

 

Surely someone on this site can do this in their sleep?

 

(paging Basilicus...)


In Topic: Rotating wing mast

07 February 2014 - 04:32 PM

I seem to recall Tom Speer saying that he had changed his mind -- originally endorsed the "slight over-rotated, fair leeward curve" school-- and has moved to a "point it directly at the apparent" theory.

 

Does this ring a bell with anyone?  might have been Boat design.net.


In Topic: Rotating wing mast

06 February 2014 - 08:38 PM

Soma. in your discussions with the best and brightest, is it "No" because there are costs (weight, less control over forestay tension whatever)   which offset the aero benefit of a rotating wingmast-- or is it that they think there is NO aero benefit at all?