Dear authors,

The paper focuses on assessing the impact of support structural orientation of metocean conditions to performance of offshore wind jacket. The findings are useful for researchers and engineers who work in wind energy fields. In the reviewers' opinion, the paper can be considered for further process. However, the following points need to be clarified:

1. Page 7: Where are the dimensions of the jackets (jacket properties) from? Were these derived from the existing jacket substructure of the IEA 15MW OWT? Please briefly summazing the jacket preliminary design.
2. Do the dominant frequencies of the whole system check in the preliminary design? And what are the frequency ranges for 1P and 3P from? Source is missing.
3. The coordinate system of the model must be illustrated. Currently it is very hard to work out the applied moment and force loads. Where are the loads exactly applied.
4. The results from parametric studies (Tables 8-9) should be graphical reported. The polar diagram, which shows how the response polarized under the metocean condition, is recommended.
5. The use of 15MW Wind turbine with the reference site condition in this paper does not reflect for substructures with different topological configuratons (such as Pratt, Warren brace systems). The author could mention that what should be considered with others?

The article carries through a check of offshore wind turbine jacket foundation members, including braces and pilings, when subjected to directional extreme 50-yr wind and wave conditions. Such checks are often done across thousands of DLCs for wind turbine designs done commercially, but often the turbine, substructure, and foundation members are de-coupled from each other. This article provides a novel look at a coupled analysis of all 3 components subjected to realistic conditions off the Massachusetts coast. Some technical considerations are listed below:



1. The derivation of the 50-yr omni directional extremes is overly simplified, and overestimated in terms of magnitude. The directional data should be combined and the extreme value analysis done over the entire history of wind/waves to obtain the omni-directional magnitudes, which are typically smaller than the worst case direction, as are used in this manuscript. The careful selection of directional bins and omni-directional data have a strong impact on environmental magnitudes, structural loads, and overall reliability, as examined in : Forristall, George Z. "On the use of directional wave criteria." Journal of waterway, port, coastal, and ocean engineering 130.5 (2004): 272-275. and Feld, Graham, Philip Jonathan, and David Randell. "On the estimation and application of directional design criteria." International Conference on Offshore Mechanics and Arctic Engineering. Vol. 58851. American Society of Mechanical Engineers, 2019.

2. A brief discussion on the relative impact on the current loads to the overall total system loading should be included. The 2 m/s current load in line with the waves may overshadow the effect of the the wind loading on the structure. The likelihood of such an extreme current occurring simultaneously with the 50-yr wind and 50-yr wave for a given directional bin has a real recurrence interval of much larger than 50-yrs, and is likely overly conservative. The reviewer suggests running a sensitivity study of at least one additional current speed, 1 m/s for example, to determine whether the trends in wave directionality controlling optimum platform orientation hold constant.

3. A consideration of DLC 1.6, where the turbine is operational with conditional 50-yr waves is considered in a full jacket design, and may be found to control the maximum member forces in certain members, especially near the top of the structure. At a minimum the wave conditions for DLC 1.6 near the rated turbine wind speed should be presented, along with a comparison of the turbine thrust loads at rated vs. idling with and without yaw error. With those data inference may be made as to whether DLC 1.6 might control for certain members and orientations.

4. A robustness check is often required for jackets, for example in API RP2A, which requires checking the jacket for 500-yr conditions without load factors, and can sometimes control the sizing and orientation of the jacket. How might the loads change if these environemntal conditions were to be introduced into the directional analysis?