It is metal with 4 fins and no markings. There is a hole drilled through it. I believe the previous owner of the house was in the US military in the 1940s or 1950s.
It looks like some sort of military shell but there are no markings.
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The ictures are so frustratingly perplexing. The first three fail to capture the essence of its 3 dimensional shape and the last one looks like a completely different, but related item.
Ww1 pilots use to fly over and drop metal “bombs” that had no explosive in them just gravity on the enemy. This looks like a reproduction of one of those.
Looks a bit like it but photos don’t show enough, description states it has 4 fins and is hard to determine but doesn’t appear to have the front hole.
Where the hole is, is the object perfectly balance at that point? To me it looks like an object that shows you what direction the wind is blowing.
I would guess downrigger weight for fishing. The hole is for a rope or heavy line of some kind, then the fishing line is attached somewhere higher on the rope. Toss it all out of a boat in a deep lake, then you can troll your bait at whatever depth you choose. The torpedo shape keeps it pointing one direction so it doesn’t spin and tangle the line.
It’s definitely this, I’ve seen downrigger weights shaped like these torpedos before.
Most likely home made. We use weights in different shapes and sizes and most of them are home made by hobby metal workers.
This is the answer, they also have other uses for counterweighting things in the water and come in many sizes.
I’m a hydrologist and we use a number of them in different weights to keep our gauging boats level in high flows.
Obviously we call them bombs.
The picture on page 14 clearly has “Center Hole (water inlet)” at the front tip and Center Hole (water outlet) at the rear end and holes in the fins. OP’s picture clearly has no such holes and I’m pretty sure “Water Inlet” and “Water Outlet” are going to pretty important to the function of the device you linked.
I was thinking that, too- I bought one from the surplus company Jerryco maybe 30 years ago, and it was kind of similar. Jerryco (now American Science and Surplus) used to get the weirdest darned stuff.