Has SHAFTKIT been
Yes. Results from SHAFTKIT
have been verified both at full-scale, and against other finite
Can I use the results from SHAFTKIT for
submission to classification organizations for approval of vibration
and alignment ?
Yes. A number of vessels have had SHAFTKIT calculations approved
by classification organizations.
Does SML provide shaftline analysis and
measurement services ?
Yes. SML has conducted a number of theoretical analysis and
full-scale measurements of marine shaftline vibration and alignment
conditions, including shaft alignment measurements using strain
gauges. Please contact SML for further information.
Does SML offer support services ?
Yes. SML offers a range of support services, in addition to
our extended support with SHAFTKIT. Please contact SML for further
Can I apply offsets to account for thermal
expansion of gear bearings ?
Yes. There is an option to input an offset from datum for each
What options are there for applying viscous
Viscous damping can be applied at the propeller, or at any location
along the shaft. Viscous damping is an input parameter for each
bearing. The bearing stiffness can be set to zero if the user wants
to apply concentrated viscous damping without a bearing support.
What options do I have for applying alternating
torsional sstresses on shafts ?
Sinusoidal torsional loads can be applied at any location on
the shaft, and at any frequecy. Multiple sinusoidal loads with varying
frequencies and magnitudes can be applied at any location on the
Can I apply my own custom input force time
A simple quick basic utility program is available that will
enable the storage of a custom force time hstory that the SHAFTKIT
program can read and utilize. We are planning to include an option
to allow for the direct input of additional load time histories,
such as prime mover transient loads, in the next version of SHAFTKIT.
Please contact SML for further details.
How do I account for propeller overhang
when constructing a static alignment or lateral vibration model
The overhang of the propeller is produced by inserting a shaft
element between the propeller and the aft end of the tail shaft.
This element should have a length that is equal to the distance
from the aft end of the propeller shaft to the centroid of the propeller,
a density of zero (0), an outside diameter approximately equal to
the propeller hub diameter, and an inside diameter of zero (0).
The default elastic modulus for steel is sufficient (2.07 Gpa).
Other alternative methods can also be used. Please contact SML if
you require further information.
How do I calculate the forward and counter whirl frequencies
from the lateral vibration natural frequencies ?
The gyroscopic effect of the propeller results in a forward
and counter whirl frequencies which generally differ from the lateral
vibration natural frequency by only a few percent, and it is commonly
neglected in whirling (lateral) vibration calculations. However,
an estimation of the ratio of the forward and counter whirl frequencies
to the lateral natural frequency can be made by using various algorithms.
Please contact SML if you require further information.