New VPP

Impressive work indeed, added to your previous ones, you really addressed all the complexity of a sailboat. To also input a sea state is challenging because the consequences are numerous and complex to assess, for the extra drag as for sails efficiency drop when the pitch motion are no longer negligeable.
 
Dolfiman said:
Impressive work indeed, added to your previous ones, you really addressed all the complexity of a sailboat. To also input a sea state is challenging because the consequences are numerous and complex to assess, for the extra drag as for sails efficiency drop when the pitch motion are no longer negligeable.
Click to expand...
Thank you, Jean-Francois, for your interest in my work! The influence of the sea state, like you describe it, is indeed extremely difficult to assess. I used the simplified version of the latest Delft-coefficients, that you discussed some time ago in a thread. It is better than nothing :-).
 
Luigi Pinelli said:
excuse me, can I use your program for catamarans?
Click to expand...
Sorry, no, it can not simulate catamarans. Maybe I can find the time in the future to adapt the program for catamarans.
Thanks for your interest
Uli
 
I did a tentative VPP for a sailing catamaran, here below. Not very difficult actually, you just have to consider two hulls windward and leeward functioning at different sinkage and Froude (the windward hull having a shorter waterline length than the leeward length). The core issue is the extra drag due to the waves interaction between these two hulls, but the more the wind and the heel angle, the less the windward hull trace in the water, so the less the expected interaction with the leeward hull. A rough estimation of this interaction drag based on available model tests (Molland and al. experiences) can be judged valid enough to take into account its influence on the total drag. It is also quite easy to continue the computation up to the windward hull out of the water. I am sure that Uli can develop a more complete tool in line with his exhaustive development on the subject.
Gene-Hull Catamaran 3.0 and SA-VPP catamaran 1.0 | Boat Design Net
(PDF) Resistance experiments on a systematic series of high speed displacement monohull and catamaran forms in shallow water (researchgate.net)
 
New update!

The update UliSpeed_2.7 is available on my website: Velocity Prediction Program UliSpeed https://www.remmlinger.com/UliSpeed.html
After you have finished the optimization, the program will write now scripting files that can be read by the CAD-programs RHINO or DELFTship. The CAD-program will automatically create 3D-surfaces of the flying shapes of the sails. No other VPP provides such a level of detail about the shape and trim of the sails. Attached are screenshots of the Pogo 40 S2 at a true wind angle of 40° and a wind speed of 16 knots. The CAD-Program is Rhino5. The lines on the sails are sections in the direction of the streamlines.
upload_2024-7-17_22-9-43.jpeg
upload_2024-7-17_22-11-19.jpeg
 
You must log in or register to reply here.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.

    • Similar threads

    Remmlinger
    New update for my VPP with 6-DOF
    Replies
    11
    Views
    966
    HelmutSheina
    HelmutSheina
    Dolfiman
    Gene-Hull Sailboat new version 3.5 and its post applications Gene-Stab and Gene-VPP
    Replies
    6
    Views
    4,544
    Dolfiman
    Dolfiman
    M
    ORC VPP – Offset File Viewer - poke through
    Replies
    0
    Views
    1,600
    MST3000
    M
    M
    ORC VPP limits
    Replies
    7
    Views
    2,535
    MST3000
    M
    Dolfiman
    Gene-Hull Dinghy 3.1 and its post application VPP in connection
    Replies
    5
    Views
    4,383
    Yves Pfister
    Y
    Back
    Top