Anyone know what this is?

Jan 19, 2010
12,577
Hobie 16 & Rhodes 22 Skeeter Charleston
It looks like a rubber bung used to stop a hatch from banging on the frame when closed hard. See if there is a hole on the underside of the hatch that the nub will fit into.
 
Nov 6, 2006
10,095
Hunter 34 Mandeville Louisiana
I have poked around my 34 for many years and not seen that piece part. I dunno!
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,164
CAL 35 Cruiser #21 moored EVERETT WA
It looks a lot like a spring retainer cap. Bit rusted and a heavier weight than the ones I have used.
 
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Likes: Will Gilmore
May 27, 2004
2,055
Hunter 30_74-83 Ponce Inlet FL
I can't see any normal holes in it, But...
It might be a very old shaft coupler that somehow got left in the engine bay when a new one was installed.
 
Oct 19, 2017
7,982
O'Day Mariner 19 Littleton, NH
axle cap like off the a cooler

hard to tell without a size reference
The rollers on my trailer have caps like that holding the axles on. They just tap on over the end with a hammer, to hold the shaft in place. My wheel barrels use the same system.

-Will
 
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Likes: rgranger

RoyS

.
Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
I have a cup on a shelf in my boat full of stuff like that that I find lurking about with no obvious place to belong. Every once in a great while I find a widget missing from something and I might find it in that cup.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,164
CAL 35 Cruiser #21 moored EVERETT WA
Yes Will.
My grandkids electric car uses the same part to hold the wheels on the shaft.
“spring retainer cap”.

1653485503504.jpeg
They come in a lot of different shapes and sizes. They pop on over a screw or shaft. Use spring of the metal cap to hold in place. When they fail, as @Crazy Dave Condon says, they are crap. A one and done solution when die cutting threads takes more time than you want to spend.