My family and I recently took the Argosy Lock Cruise from Lake Union, through the Hiram M. Chittenden Locks, to the Seattle Waterfront, aboard the Goodtime III. The ship’s main engines are Caterpillar 3408’s coupled with Twin Disc MG514 reduction gears. Auxiliary power is supplied via two 27 kW diesel generators.
The Caterpillar 3408 diesel engine’s maximum shaft speed is 1800 to 2100 RPM (30 to 35 Hz) depending on the model subvariant.
I made sound & vibrations aboard the ship using my Android Smartphone. The sound measurement was taken at first level at the aft end. The vibration measurement was taken on a bench in the upper deck. The measurements were taken at two different times.
The spectral peaks in both plots are due to the main engines, drive train and the auxiliary generators.
The two side-by-side peaks near 24 Hz in each case could be due to the two engines running at slightly different speeds and at about 75% of maximum speed. The pair of peaks near 16 Hz could then be the propeller shaft speeds assuming a 1.5:1 gear reduction ratio.
Note that the Twin Disc MG514 reduction gear is available in various ratios.
– Tom Irvine
Hello, Tom!
Great to hear from you, as always!
I’m finally uncovering a boatload of our Deer Valley Site deficiencies for vibration data acquisition, shock, etc. and I happen to get several tasks involving vib and shock data collection & analysis.
Fortunately, I have built up a number of contacts throughout the years so I was able to obtain some DAQ systems & software, and using OriginPro I could run all of the other calculations, filtering, ASD to DSD, integrations, etc.
Anyway, I would love to see about having you teach a class for our site/engineers, then I could cover the rest of the training/post-training, as necessary.
Our site was gutted a number of years ago in terms of capability for recording and analyzing vibration/shock data, as I am learning, and the basic things I am showing them are as if I came from planet Pluto…
Anyway, let me know if you’re still doing training, it could be over a Teams call or in-person, whatever works for you.
Let me know what you think,
Thanks!
Doug
Mr. Irvine,
Thank you for sharing that interesting information.
Jesus