strange rubber bung

[soleil d`or]

Yes electrosis it does expand a slight amount when the bolt is inserted in any of the holes and it would be enough to lock the bung in position.
Push the bolt out from the top and the plug could be released.
But would have to be located inside a tank or pipe on a lanyard in the first place.

 

[bigwow]

Fancy drill bit holder?

 

[electrosys]

Yes electrosis it does expand a slight amount when the bolt is inserted in any of the holes and it would be enough to lock the bung in position.
Push the bolt out from the top and the plug could be released.
But would have to be located inside a tank or pipe on a lanyard in the first place.

Well - I just want to say how grateful I am that you posted about this, for whatever conclusion is eventually reached about the purpose of this gizmo ... it's helped me to decide upon a method for sealing the drain hole on my fishing boat - something which has been bugging me for ages. I particularly wanted the hole to remain level with the sole to ensure that no rainwater remains behind, and yet I wanted as little as possible sticking out from the transom when the hole is sealed. An expandable bung (wing-nut plus washers etc) is the ideal solution.

Yet again, the PBO Forum comes up with the goods ...

 

[LadyInBed]

Dingy drain plug bung?

 

[penfold]

Could it perchance be a cunning device to attach the bitter end of the anchor chain to a strongpoint within the chain locker?

Or related to this, the hook bit is attached to the end of your chain and plugs the chain pipe? Obviously only of use if you like your foredeck 'nice and tidy' and chain-free.