shroud attachment...steel or aluminum

[zoomee]

boat is a 1972 Morgan 42 MkII. The shroud chainplates are attached to the hull via big stainless bolts into a three foot long section of steel u channel beam...four inches wide and maybe 1/4 thick.

The u beam is very corroded and need to be replaced.

I am thinking of replacing with aluminum to reduce the corrosion problem.

Make sense? Issues to worry about?

How do I size the aluminum beam to get the same strength as the original steel?

[water addict]

You need to find out what grade of steel the original chainplate is. You'd be safest replacing with a high grade stainless of similar/same size as the original. If the attachment from the turnbuckle is stainless, it's probably not a good idea to connect a steel pin to an Aluminum chain plate. Good marine stainless grade AL6XN.