The MV Tacoma is a ferry that runs between Seattle and Bainbridge Island. MV stands for “motor vehicle” and is used to designate a ferry. The ferry’s size class is “Jumbo Mark II.”
The total engine power is 16,000 hp from 4 x EMD 16-710G Diesel-Electric engines. The maximum engine speed is 900 RPM or 15 Hz. There are two shafts with propellers. One each at the forward and aft ends of the ship.
There are plans to convert the engines to a hybrid diesel-battery system to reduce exhaust emissions. The Siemens Company will perform the modification.
I traveled on this ferry on September 6, 2021. I recorded the following vibration data using an accelerometer app on my Android Smartphone (Pixel 3 XL), which was placed on a small table between two seats on the passenger deck.
The Fourier transform has distinct spectral peaks at: 12.8, 25.6, 38.4, 51.2 Hz.
The 12.8 Hz peak is due to the engine shaft speed at 85% of its maximum speed. The shaft speed is set to optimize fuel efficiency, minimize engine wear, etc. The three remaining frequencies are integer harmonics of 12.8 Hz. A number of lesser, unidentified peaks are also present.
The sample rate was 400 samples/sec. The Fourier transform was calculated over a 24-second duration.
The Fourier transform was calculate using the Vibrationdata Matlab GUI package
– Tom Irvine
Hi Tom,
I really appreciate the article; very interesting how its characteristics were ‘revealed’ and laid bared to the community. I wonder if it would feel nakedly bashful. If so, it deserved it…..
Regards,
>
Hello, Tom!
Great to hear from you and see you continuing to educate people on vibration and shock design, troubleshooting, etc.
I am finally getting the attention of upper and executive management at Honeywell and would love to get your course brought to Honeywell at my location in Deer Valley, AZ (north Phoenix, I assume you recall).
Doug
Thank you for the interesting post.
When I performed sine burst testing, integer harmonics of excitation frequency occur
like your measurement result.
I would appreciate if you could give the reason why the integer harmonics occur.
Best regards,
Juwon Jeong
Very nice random processes. I would like to work with them. 1. Sufficient realisation length. 2. Selecting the service regimes basing on cluster analysis. 3. all in the time domain.
Could we cooperate?
Have a good day.
Irina Gadolina
Hi Tom. I like your post about MV Takoma. Could you please allow me to use the picture of the random signal from your post as an illustration for my report at ICMFM XX WROCLAW 15.09 – 17.09.2021 Conference? With referring. Sincerely, Irina Gadolina >Вторник, 7 сентября 2021, 3:14 +03:00 от Vibrationdata : > >tomirvine999 posted: ” The MV Tacoma is a ferry that runs between Seattle and Bainbridge Island. MV stands for “motor vehicle” and is used to designate a ferry. The ferry’s size class is “Jumbo Mark II.” The total diesel engine power is 16,000 hp from 4 x EMD 16-710G ” >
You may use anything on my blog for your research and conferences. Best wishes, Tom