...or just an old knife

[Ret10Echo]

Seeking some insight on the attached photos. I'm not a blade guy so figured this group is where the expertise lies.

There is little background on this from the owner other than "It was my grandfathers" and "he was in the war" (WW-II) .

It has seen better days.

Before telling him to just oil up the blade and treat the handle I figured I'd see if there was any insight on whether this is a specific type or "just an old knife" and a keepsake memory of his granddad.

Thanks ahead of time for any feedback.

R10

[JJ_BPK]

It has a couple tells:

1)hilt & pommel are brass and round << dive knife (c attached)
2)hilt NOT threaded for brass sheath << Most DIVE knives were retained by screwing the knife into the sheath (c attached)
3)blade was heavenly ground just in front of the hilt << well used and loved
4)leather stacked ring handle << most dive knives used wood for durability << c attached
5)leather grip & sheath << leather does not last in salt water

My money:

Shape and style suggest Navy, most Grunts wanted a hilt for thrusting.

It could be a "Trench Art" knife, for personally use, made from some other knife.

Value??: more value to the loved one than open market,, BUT I am not a spurt.....