Miniature Wooden Ships - what are they?

These are very cool small, painted wooden ships (some of them are VERY small, see the reference to the quarter in the photos). They are painted various shades of green and gray (about 5-6 different colors total). They all have a pinhole in the backend that I presume was used when carving and/or painting them. I found them in my father's attic after he passed away. The house was originally owned by my grandfather, so I'm not sure if they belonged to my father when he was a boy (he was born in the 20's), or to my grandfather. I have googled and searched the internet to find information on them, but have found nothing. There are no labels or markings on them except that some of them have letters and/or numbers carved into the bottom or handwritten in pencil. They are very cool, appear to be hand-carved since no two are EXACTLY alike, although very similar. Any ideas? I'd love to know more about them!