Thanks Rick,
Lazy of me to not double check my numbers. Your are completely right. The ratio between square and round is sqrt(4/pi) (not 4/pi), which is a difference of 13%, and aligns with your numbers above. (Without perfect ratios in the rectangle, the difference was probably 15% in Michlet, which is the number I had remembered.)
Interesting that the flare makes such a difference, but it makes sense! Thanks again, and sorry to everyone for posting the wrong numbers.
So with some rounded corners of the flared hull, the difference is even less than 5% - nice!
On Fri, Jun 1, 2018 at 11:41 AM, Rick Willoughby rickwill@bigpond.net.au [harryproa] <harryproa@yahoogroups.com.au> wrote:
No - that is with hard chine. Michlet will not produce a full hard chine unless section shape is constrained but it does make quite a tight radius even if unconstrained.
As an example, if you take a section area of 0.1sq.m on a length of 10m then the wetted surface area ifor various sections are:Semi-cicrle 7.93sq.mRectangle 2 wide to 1 deep 8.94sq.mSquare section 9.48sq.m3-side with flare of 28 degrees 8.33sq.m. ( I checked number and found it was 28 degrees not 26 as stated earlier)So the best 3-side is 8.33/7.93 = 1.05 ratio of wetted surface (these numbers are rounded from what i stated earlier)On 1 Jun 2018, at 6:15 pm, Björn bjornmail@gmail.com [harryproa] <harryproa@yahoogroups.com.au> wrote:Rick, many thanks for interesting info. I don't follow completely. But I think I a flared hulls needs to be quite rounded between bottom and sides to only get 5% more surface area. I never tried the 32-series in Michlet myself.
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