×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Current Yaw Moment Arm for Mooring Systems

Current Yaw Moment Arm for Mooring Systems

Current Yaw Moment Arm for Mooring Systems

(OP)
In publications such as DM 26.5, the current yaw moment arm vs. current angle for a moored vessel is zero at 0 degrees, rises then begins to decline around 20 degrees, crossing the x-axis around 90 degrees and continuting to decrease until around 160 degrees, then rising to zero at 180 degrees.  Other publications depict this almost as a sine wave, similar to wind yaw moment.

In MIL-HDBK-1026/4A, graphs of this kind are replaced by a least-squares fit function (Equation 24, 4.5.3) which generates a sawtooth type function that begins at a negative value at 0 degrees, passing the x-axis around 90 degrees and ending up with a positive value at 180 degrees.

Allowing for a sign convention change, the non-zero values for the current moment arm for current angles of 0 and 180 don't make sense.  Is there something wrong here?

Note: both DM 25.5 and MIL-HDBK-1026/4A can be found at http://www.vulcanhammer.net/marine/.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources