It's been a few years since I've disassembled the mast head, but my recollection is that if you remove the bolt that holds the two upper shroud tangs in place, the whole assembly can be pulled free from the top of the mast.  That would give you full access to to the inside of the mast, and access to both sides of the top plate.  No need to drill out the rivets, or mess with the little round piece.

--Peter


[ Sent From rhodes22.net ]

> On 2025-05-10, at 23:52:22 EDT, peter beckerman wrote:
>
> Hi All,
>    I’m looking to add an antenna and an anchor light to the top of my mast. 
> There’s a plate riveted to the mast top, and what looks like a little access 
> hatch held on by three screws.  On mine two of the screws are rusted shut.  My 
> question is:  what is this cover?  Can I just drill out the rivets holding the 
> mast top plate and remove that along with the little cover? 
> 
> Thanks so much for your help
> 
> Peter
> 
> [ Sent From rhodes22.net ]
> 
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