I believe the answer to this question is much simpler than I’m trying to make it, but I can’t figure it out. What is the formula for calculating the width of a ship track with each additional angle of crab? Example: 600’ x 106’ ship. With zero crab angle, track through water is 106’ wide. When h…

I don’t know the definition of track width, but it sounds like a right triangle problem where the ship length is the hypotenuse and the crab angle is theta. why not say Cos of crab angle is track width over length?

So for a 600’ at 5 degrees, it’s an additional 52 feet? So your sweep path (thank you for that proper terminology) is 158?

Oh ya, Sin. I had the wrong angle mind for crab.

I don’t think that there is a formula for this unless it is loosely related to the formula for squat. Which is bollocks. What are the wind conditions? What is the swell? What are the local top and bottom layer currents? Subsea contours? What is your hull form? Trimmed by the head or by the st…

While I sort of agree with you, I’m looking for some numbers to make an argument one way or another for certain reasons. Knowing how wide the ship becomes when crabbing is helpful for this.

Yeah, I get 52 feet, plus your beam. If you have to calculate sweep path you’re not going to have a good day.

Yea, well, that’s why I’m trying to calculate it. To avoid that.

There is no formula that you can rely on! It is futile. If you are part of a management team attempting to lay down fixed rules for Bridge Teams to apply then good luck with that. If it is a an academic exercise then go out and try it!

Math Nerds - Help! - Calculate Swept Path

Professional Mariner Forum

Kennebec_Captain October 17, 2020, 11:02pm 3

It’s called sweep path.

The additional width = LOA * Sin (drift angle)

8 Likes

Box boat aground in Suez Canal

Topic		Replies	Views
Ship Squat calculator by www.thenavalarch.com Professional Mariner Forum	0	4308	December 31, 2014
Chart formula - navigation question Maritime Training & Licensing	20	7601	May 15, 2012
Seakeeping for Autonomous Ship in Heavy Weather Professional Mariner Forum	90	9463	February 27, 2020
Following Seas and Follow Up Steering Professional Mariner Forum	17	6179	October 12, 2016
Amount of Scope for Anchoring - Dragging Anchor info Professional Mariner Forum	25	17589	October 21, 2014

Math Nerds - Help! - Calculate Swept Path

Related topics