Neural
nets and genetic algorithms
Miscellaneous Musings from the Technical Director
Monday, 9-JUL-2007 by Donald
MacPherson - Technical Director
I received an email from one of our software
customers mentioning a new technical paper about the use of neural
network (NN) techniques for the prediction of residuary
resistance. This is something that I have discussed in a past blog
article, and we have internally investigated for almost 10 years. The
authors' contention was that their NN-based dimensional analysis
resulted in improved quality of the prediction. Let me tell you why
the authors are, at the same time, correct and yet also very, very
wrong...
[
Full
Article |
Comments
]
Different
gear ratios and unbalanced propeller thrust
Miscellaneous Musings from the Technical Director
Monday, 30-APR-2007 by
Donald MacPherson - Technical Director
We had a call this week from a PropExpert user (a
propeller distributor) who was working on a project for a potential
customer. It seems that the owner of a twin-screw boat was repowering
and wanted to use different reduction gear ratios between the port
and starboard engines. The question to us was regarding how to
best size the propellers, as well as the implications of using
different ratios and propellers...
[
Full
Article |
Comments
]
Deficiencies
in shaft diameter calculations
Miscellaneous Musings from the Technical Director
Monday, 16-APR-2007 by
Donald MacPherson - Technical Director
As part of our development for the shaft
sizing calculations in PropExpert over the course of the last
couple of years, we contacted ABYC regarding what we believe is a
significant potential problem in their recommended shaft sizing
calculations...
[
Full
Article |
Comments
]
Replies
to PropExpert Survey Comments
Wednesday, 2-APR-2007 by
Donald MacPherson - Technical Director
Periodically, we ask our software customers for
feedback by way of a "user survey". We recently conducted
such a survey for our PropExpert users, and the responses are now
coming back to us. The respondents from this round of surveys offered
up some particularly interesting comments, critiques, and
suggestions, so we felt it would be valuable for me to provide an
on-going discussion of these as a blog article. And here we go...
[
Full
Article |
Comments
]
CFD:
Computational Fluid Distraction?
Miscellaneous Musings from the
Technical Director
Monday, 02-OCT-2006 by
Donald MacPherson - HydroComp Technical Director
I read a thread about "hull speed" last
week on a boat design forum. The topic of hull speed is something that
particularly bothers me for a number of reasons, some of which I put
in a small report Hull Speed (pdf) that you can find on our web site.
However, the thread actually took an interesting turn into the
components of wave-making drag and CFD. The real gem in this
thread is one sentence, which I hope the author will not mind my
quoting here..
[
Full
Article | Comments
]
|
