Aluminium on the boat

[pcatterall]

My instinct is that aluminium on a boat is a no no but then our aluminium masts seem to survive ( though I guess the anodising will help!)

We have an aluminium ladder aboard, it lives on the deck lashed to the rail and serves as a gangplank and boarding ladder. It has survived 3 years with no serious corrosion visible.



I an now making a (sort of) swimming platform which will double as a ‘stand off’ for the boarding ladder to offset the inwardly raking transom.


I want to use aluminium channel for the sides of the platform as SS channel seems to be limited in sizes and very very expensive.


Bearing in mind my experience with the ladder is using ally such a bad idea?


PS could I use brass (rather than stainless) screws to secure the wooden slats into the channel



Thanks as always

 

[NormanS]

I used aluminium angle, bolted to the alloy toe-rail, to mount midship mooring cleats. No problems.

 

[lw395]

Ali can be ok, it covers a multitude of sins, i.e. a whole range of alloys, with or without anodising.
Brass is a no, either stainless fasteners and Duralac or ali rivets can be OK.
Also gluing with epoxy can be made to work.

 

[charles_reed]

Depends on the alloy used - there are specicial marine alloys, which won't just fizz in the sea.
Marine alloys
5052 aluminium alloy
5059 aluminium alloy
5083 aluminium alloy
5086 aluminium alloy
6061 aluminium alloy
6063 aluminium alloy
You may find their costs not far different to stainless, bearing in mind you need to double the section wall-thickness. They are far lighter.

 

[pcatterall]

Depends on the alloy used - there are specicial marine alloys, which won't just fizz in the sea.
Marine alloys
5052 aluminium alloy
5059 aluminium alloy
5083 aluminium alloy
5086 aluminium alloy
6061 aluminium alloy
6063 aluminium alloy
You may find their costs not far different to stainless, bearing in mind you need to double the section wall-thickness. They are far lighter.

Thanks but I doubt if my ladder is anything special and that has lasted well (as stated.)

 

[William_H]

Aluminium is quite OK o a boat indeed many even large boats are made of aluminium. The real roblem comes when it is in contact with other different metals. Here you must insulate the metals from one another. Duralac is the common way. But one would never use brass in ali. That just makes a battery. good luck olewill

 

[pcatterall]

Thanks all, I will try the aluminium. The stainless hinges will be to the wood component so it is just the screws to hold the wood in the aluminium channel so SS screws and duralac it is

 

[prof pat pending]

Thanks but I doubt if my ladder is anything special and that has lasted well (as stated.)

That would depend where you ladder came from, marine grade ladders are available.
I'm pretty sure that all ladders sold in the UK conform to a British Standard, so it won't be a case of any old alloy being used.