The only time I have seen metal rivets
: are on aluminum canoes, or are the rivets just screws or nails?

: Jag

In lapstrake construction, some people use copper nail to rivets the strips together. sometimes the nail just was simply cinched and sometimes nail end was mushroom. This was done by clipping off the pointy end at about 1/8 inch pass both strips. The clipped end was supported by a heavy weight metal ( I forgot the term for that.) and hammerring on the head. This was usually done by two people.