What are these?

I've got a couple of things here that are totally unrelated. They both appear to be quite old. The one looks kind of like a knife but the handle isn't quite right for that. Any ideas on what they are?
Thanks for your replies. This place is a wealth of knowledge an d I am very grateful!

 

Spear tip and Navy dolphins and submarine symbol.

 

Thanks Hollyblue! When I looked at spear tips on ebay it appeared that some of them were on the top of old lightening rods. We used to have an old lightening rod around here and maybe that was part of it.
My brother was in the Navy and a collector of all things Navy related.

 

I think the the "spear tip" may be be a ship/submarine letter opener like this one.

https://picclick.com/WWII-Era-Submarine-Letter-Opener-Made-at-361934399362.html

 

Thank you Say_it_Slowly! Shows how much I know. The two things ARE related because they are both Navy items. I still wonder what that little pointy part on the handle was for. Seems a little awkward on a hand tool.

 

I think it's just the tower.

 

That makes sense. Thank you!

 

One's just a shiny letter opener....the other's just rusty and older!!