Boston
05-30-2009, 02:28 PM
Hi folks and thanks for all the help so far
Most of you know what Im up to and your help with the electric system drive system and various other elements of my project has been invaluable ( with a special thanks to both Par and Rick for there straight forward approach in offering various tidbits of info and advice )
Im attempting to optimize a hull form for open water cruising in the north Atlantic area
the original hull form of the look I liked best is not suited to open water cruising and so Im thinking that a move towards a semi displacement hull would be a reasonable start to get me the speed and efficiency Im after
60' wood hull
13.5 beam
~4 draft
42000 lb displacement
10-12 knots cruise
~15+ knots top speed on 250 hp
speed considerations need to be reasonable for the average sea state and wind condition
I had considered the down east hull form since its one Im familiar with but at this size its seems a bit wrong somehow
I need a place to start from and the basic semidisplacement seems to be it
chines
soft or hard
what are the various performance characteristics of each at varying speeds is my first question
my next would be is there a significant penalty for adding bilge keels and reducing the keel accordingly
and thirdly entrance angle
14 degrees is what I always thought but I learned that a long time ago and things change
Im not really trying to draw a set of lines but just understand the design principles I should be looking for in an efficient hull design
maybe develop a list of parameters to bring to an NA when the time comes
Most of you know what Im up to and your help with the electric system drive system and various other elements of my project has been invaluable ( with a special thanks to both Par and Rick for there straight forward approach in offering various tidbits of info and advice )
Im attempting to optimize a hull form for open water cruising in the north Atlantic area
the original hull form of the look I liked best is not suited to open water cruising and so Im thinking that a move towards a semi displacement hull would be a reasonable start to get me the speed and efficiency Im after
60' wood hull
13.5 beam
~4 draft
42000 lb displacement
10-12 knots cruise
~15+ knots top speed on 250 hp
speed considerations need to be reasonable for the average sea state and wind condition
I had considered the down east hull form since its one Im familiar with but at this size its seems a bit wrong somehow
I need a place to start from and the basic semidisplacement seems to be it
chines
soft or hard
what are the various performance characteristics of each at varying speeds is my first question
my next would be is there a significant penalty for adding bilge keels and reducing the keel accordingly
and thirdly entrance angle
14 degrees is what I always thought but I learned that a long time ago and things change
Im not really trying to draw a set of lines but just understand the design principles I should be looking for in an efficient hull design
maybe develop a list of parameters to bring to an NA when the time comes