根据我个人的了解，如果您仅谈论COCO数据集，我认为它们没有船舶类别。他们拥有的最接近的类别是船。这是检查可用类别的链接： http://cocodataset.org/#overview

From what I personally know, if you're talking about the COCO dataset only, I don't think they have a category for "ships". The closest category they have is "boat". Here's the link to check the available categories: http://cocodataset.org/#overview

顺便说一句，船类中也有船只。

BTW, there are ships inside the boat category too.

如果您只想选择图像某个特定的COCO类别，您可能需要执行以下操作（摘自COCO的官方演示并进行了编辑）：

If you want to just select images of a specific COCO category, you might want to do something like this (taken and edited from COCO's official demos):

# display COCO categories
cats = coco.loadCats(coco.getCatIds())
nms=[cat['name'] for cat in cats]
print('COCO categories: \n{}\n'.format(' '.join(nms)))

# get all images containing given categories (I'm selecting the "bird")
catIds = coco.getCatIds(catNms=['bird']);
imgIds = coco.getImgIds(catIds=catIds);