Calculation Methods of Icebreaking Capability for a Double-Acting Polar Ship
Round 1
Reviewer 1 Report
Introduction
In row 35, the authors refer to “two important dimensionless coefficients”. I suppose that these coefficients are the speed–dependent icebreaking length coefficient and the bending capacity coefficient. If right, please make them explicit immediately. In other terms, you should provide definition and formulation
In row 38, cancel the whole sentence “Two methods are tried to derive icebreaking“ since the same content is stated from row 43.
Static method
1. The authors state that resistance in level ice “consists of icebreaking force and ice submersion force”. When they observed that the “broken ice floes ………... slide along the hull”, reference should be made to crushing resistance. Is this resistance component included in the icebreaking resistance? Please, clarify.
2. Lindqvist’s formula (2) for submergence resistance is not stated correctly. First, modify the factor (BT(B+T)/B+2T) in (T(B+T)/(B+2T)). Moveover, a generic bow area appears in the formula, whilst the actual formula contains ice thickness, stem angle, waterline angle, etc. Therefore, try to write the formula properly.
3. In Fig. 2, referred to icebreaking force determination, the “ice field with grids” means that the ice sheet is discretized. In the paper the authors write somewhere that the size of each panel (grid) is defined according to experiments on model. But how to use this numerical approach when you have no experimental data? The response is in formula (5). Therefore you are suggested to transfer formulae (5) through (8)
Model Tests in Ice Basin
There are too many block coefficients in Table 2! The last four characteristics are to be corrected (probably) as
Block coefficient 0.778
Waterplane area coefficient 0.892
Midship section coefficient 0.995
Longitudinal center of buoyancy (from Lpp/2) 7.593 m
Control these figures!
Figure 4 shows the old i
ce tank of Krylov. That means that model tests were carried out many years ago since there is a new, larger and more qualitative ice tank. Please, take care of the following recommendations:
- search for a photo of the new laboratory
- avoid to say that “it takes two days to generate an ice sheet”; this is not true in the new tank and neither was true in the old tank according to my experience! So, I suggest to cancel this sentence.
Sensitivity study
You should make clear how the coefficients enter into equation (4) of the dynamic model.
Moreover, for sake of clarity it should be convenient to write the formulas for these coefficients in your paper.
Formulae (5) through (8) is a very relevant contribution to definition of the length ice grid. My compliments. As suggested before, transfer these formulae after Table 2.
Editing
Enlarge figures as much as possible because some important details cannot be read!
Add a List of Symbols before or after References
In the text, write symbols in a clearer way
Changes in English language
In many places change time instant in time steps or time intervals
Row 10: ice sheets ⇒ level ice
Row 27: import ⇒ important
Row 29: seldom has studies icebreaking capability for a polar ship ⇒ icebreaking capability for a polar ship has been seldom studied
Row 128: were generated for these tests in full scale ⇒ in full scale were generated for these tests
Row 163: central gird ⇒ central grid
Row 195: to with respect ⇒ with respect (cancel to)
Row 225: in the Figs. ⇒ in Figs.
Row 239: as function ⇒ as a function
Row 269: and measured will ⇒ and measured ice resistance values will
Row 300: As described aforementioned, static method is on the basis of static ⇒ As described beforehand, the static method is based on the static
Row 316: is very close the measures ⇒ close to the measured value.
Row 396: The derivation ⇒ The scatter
Row 403: is minor within ⇒ is within
Author Response
Thank you very much for your great effort to review our manuscript!
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The presented work represents a fast engineering method to estimate ice breaking loads compared to expensive experiments or CFD-DEM simulations, which are being developed and scrutinized.
It might be very efficient for study of first-principle hull shape variations.
Please include comment on suitability for parameter identification of sensitive and unknown coefficients (use model test results for parameter identification/calibration of the model).
Please address how presented work could or could not be used for maneuvering.
Author Response
Thank you very much for your great effort to review our manuscript!
Author Response File: Author Response.pdf
