What is it??

[Peter3607]

While cleaning my engine room bilge, I found this guy at the bottom. Any idea what it is used for?

[AaHubb]

That's a service plug to keep your boat from sinking when servicing the paddle wheel sensor.
Also known as a whats'it.

..Aaron

[pepmyster]

It's a dog whistle gone wrong, only left handed dogs hear it.
That's all I know.

[Viper]

As Aaron mentioned it's a plug for the thru-hull fitting of a transducer. This type of system allows you to remove the transducer element while in the water, and allows you to insert this plug in its place while the transducer gets serviced. The plug should always be tied off or close to the thru-hull fitting so it's always on hand in case of emergency.

The housing in the hull also usually has a valve that closes automatically when the element or plug is removed. The closed valve isn't water proof so you'll get a bit of water coming in when the ducer or plug is removed but gives you time for replacement without taking on a full column of water.

[pepmyster]

Source of the post It's a dog whistle gone wrong, only left handed dogs hear it.
That's all I know.

Tried to be funny, Oh well.....

[ColRon]

Source of the post

Source of the post It's a dog whistle gone wrong, only left handed dogs hear it.
That's all I know.

Tried to be funny, Oh well.....

Don’t feel bad Pep, I thought it was funny!

[Viper]

[Peter3607]

Source of the post It's a dog whistle gone wrong, only left handed dogs hear it.
That's all I know.

That actually made me giggle when I read it. Sorry for the delayed reply.

[RGrew176]

Actually it was funny. I laughed.