  Accurate ocean surface wave knowledge is crucial for ship design. With the
significant advancements of model physics and numerical resources, the recent
numerical wave hindcast data has a potential to provide environmental
conditions for wave load estimation in the ship design process. This study aims
to quantify model uncertainty in the state of art numerical wave hindcast
products to get insight into the application of wave hindcast for ship design.
The model uncertainty is deduced based on the comparison with the wave buoys in
the North Atlantic as well as the inter-model comparison with four wave model
products. The multiple wave buoys distributed over the Northwest Atlantic and
Northeast Atlantic are considered as wave buoy arrays and used for model
evaluations. All the four models in general showed very good and similar
accuracy in the estimation of the significant wave height $H_s$. The model
$H_s$, however, deviates from buoys and also deviate among each other for the
extreme wave conditions of $H_s$>10. It is also found that there is
disagreement for the mean wave period $T_{m02}$ between numerical wave models
and the wave buoys. More specifically, the models underestimate $T_{m02}$ for
extreme wave conditions of $H_s$>10 in the Northeast Atlantic. The joint
probability density function (JPD) of the significant wave height $H_s$ and
mean wave period $T_{m02}$ for the extreme wave conditions are also derived.
Among the JPDs, the total number of samples that satisfies the extreme wave
conditions of $H_s$>10 and 8<$T_{m02}$<14 varied by 50% although the mean value
of the four model products is close to the observation. This study indicates
further model improvement is necessary to more accurately reproduce the extreme
conditions. For the model improvement as well as the model evaluation, more
measurements of the high sea states and their wave spectra information are
warranted.
