New Mast Cleat location

[VicS]

It's not that simple. You can't just look at the Galvanic series and get the corrosion rates. Read Nigel Warren's book Metal Corrosion in Boats ... I don't know of a better one for a yachty .... 224 pages .... a riveting read.

The rate of corrosion is dependent on the current generated due to the potential difference. If the less noble material .. the aluminium ... quickly coats the rivet (monel) and that coating is rugged, the action is stifled.

It gets even more complicated with brass .... common zinc brasses: the zinc leaches out in seawater and the fitting crumbles away, but not true with admiralty brass, which is actually a bronze.

Monel rivets are safe with marine aluminium alloys. It has stood the test of time.

I dont think I mentioned "rates" of corrosion, but since you have and you are refering to Warren's book perhaps you would care to tell us the rates of corrosion of an aluminum alloy in contact with the other alloys mentioned.

Brasses its true are susceptible to dezincification but I wonder if this is an issue with brass inserts in a aluminum mast. What does Warren say?

A barium chromate paste should be used with Monel rivets in aluminium

 

[TradewindSailor]

I don't think I can do Nigel Warren's book justice in a few lines on a forum.

If you want to know more about corrosion, it is well worth the read .... and a good one to keep handy.

As for brass inserts in a mast .... it's a no-no ..... not his words, mine!

I will say that on reflection Admiralty brass is quite definitely a brass.