Adze "Spike"

[Wallhopper]

Hi Folks 
I see some adzes with a flat ended slightly tapered (round or square) spike, or pin opposite of the blade.
What is it for ?
I saw it called a "countersinking Spike" in an auction ad, but no more information was provided.
Searched here as well but found nothing.

Thanks,

[wvtools]

The adzes with with tapered spike are called ship carpenter's adzes.  The spike is for countersinking nails below the decking material.  You may also occasionally find a carpenter's poll adz that has a hammer type poll on it instead of a spike.

The most common types of regular adzes are the flat head, the half flat head, the poll adz, and the ship carpenters adz.  There are also cooper's, gutter, connecticut hand, ice, railroad, lipped ship carpenter's, bowl, and others.

[Wallhopper]

Thank you much.
So I suppose some members are assemble with nails and then hewed with the adze to a final dimension afterwards ?
Can you describe other situations where one would need to pound a nail deeper to continue hewing /adzing?
I assumed that all of the whittlin' was done before assembly.
Thanks again.