Aluminum and carbon mast! Possible?

[Omeron]

For a total length of 16m keel stepped aluminum mast, if you already had the bottom section available from a used broken mast, (around half the total length) would you consider ordering a tapered carbon top half (around 7-8m) and join the two. Savings; Bottom half is already available,Manufacturing and shipping half a carbon mast should be much cheaper and easier, Weight saving at top half.
Not sure about blending sections together, perhaps the carbon section can be made to be inserted into the aluminum section,bend characteristics, how to make a satisfactory join,etc...
What do you think? Stupid idea or worth considering?

[wet feet]

Apart from such matters as differential expansion and the possibility of electrolytic corrosion,the idea may have merit.Much easier to sleeve a metal section to the available bottom half.

[catsketcher]

The idea is a very well used in dinghy masts. On a 3/4 rig skiff like boat like a 16 or 49 er a top mast is inserted into a large section aluminium bottom section. For carbon tips a light layer of E glass is neded to insulate the carbon from the aluminium or electrolytic reactions will occur and destroy the alloy.

I have one of these masts on my trailer sailr and they work well but I haven't seen them used on anything over the sport boat size - 25ft or so. As the carbon tip would not be a tip only in your case I think the engineering would be new territory. I would suggest selling your stump or taking the fittings of first - that is where most of the winches, exit blocks etc are and re fitting a bare section to save money.

cheers

Phil Thompson

[gggGuest]

Not a good idea. As the man said it is frequently done on smaller boats, but what he didn't say is that they often self destruct through electrolytic corrosion. Sleeving is particularly risky. The early masts on the RS600 class in the UK were alloy sleeved and they are quite notorious for disintegrating, to the extent that ads for second hand boats will state that the boat has the later type mast.

[MrYan]

Agree whole heartily with gggGeust