Need to Know what 'This' Is . . .

[otherthan]

the black protuberance on the hull under me?
I presume this is a dept sunder but not sure, I was going to but a hand held dept sunder, however if this is some kind of sensor and optaining a monitor to go with it make more sens, pleas let me know.

on the exterior of this plug thers a fin probably to protect the sensor?

[rebel heart]

Is there a wire running from it? If not, it might just be an old thru-hull fitting that isn't in use anymore.

[otherthan]

I dont remember any, to be honest I havent paid much attention to it.
looking at the photo got me thingking about what it is.
I will see my boat this weekend and take better photos inn and out.
I also have an old propeller under the cockpit wich is hooked on needle knotmetter. this will probably have to go too?
cheers

[Ex-Calif]

If you don't know what it is and are not using it and it makes a hole in the bottom of your boat, you may as well remove it and fill the hole.

A picture of the outside of it would be useful. The "fin" part has me curious. My wild-ass guess is an inductive speed probe, likely with temperature but pure conjecture on my part.

Forward of the keel in relatively undisturbed water. Using it would require identifying it (brand etc.) which also will likely require pulling it out of the boat and getting a better look at it.

Depth transducer would be nearer the keel and would be flat on the outside in my opinion.

[otherthan]

from what I remember it was flat, almost as if nothing went thru the hull?

you can see the fine on this photo.

I will take it off and see what it is, will post better photos