an accident waiting to happen?

[ffiill]

This morning I was waiting at Fort Augustus canal bridge whilst boats locked up into the canal.A big 60 footish cutter rigged ketch passed the bridge.
About one third the way up its tough looking main mast there was a definite clean cút break in the mast with the two sections pop riveted together presumably through an inner tube.
There were visible about four rows of rivets running around the mast both above and below the break.This was clearly observable as it was just above head height from my viewpoint on the road.
Given that in the event of any rigging failure most of the leverage would be towards the bottom of the mast is this an accident/failure waiting to happen?
A good weld perhaps but pop rivets?

 

[prv]

Mast extrusion only comes in certain lengths, for ease of transport. So any mast over about 12m will have a joint in it, and the riveted sleeve you describe is the standard method.

It's not a repair, it will be how it came from the spar manufacturer.

Pete

 

[Daydream believer]

I visit to Oysters yard & a look at some of their enormous masts will show massive pop riveted joints

 

[sailorman]

in the UK about 30ft was the max that could be anodised there fore the joins in many masts inc.mine
on the continent they were /are able to anodise longer lengths

 

[ffiill]

Thanks-just not normally one of those things you notice from deck level

 

[30boat]

My mast has a joint but instead of pop rivets it has machine screws,loads of them.

 

[savageseadog]

The Sigma 38's all have joined Selden sections

 

[Strathglass]

The mast extrusion I bought when building my boat was about 17 metres long when I collected it and there are no joins in it. It was made in France.

There are many craft rigged with a mast formed in two sections joined together with rivets. It is a much better than welding as the heating when welding can affect the strength of the mast near the weld.

But I have also seen the masts on several hire yachts successfully welded at about spreader height subsequent to them playing at follow the leader and attempting to pass under unopened bridges behind cruisers when the bridge had not been opened on the very same Caledonian Canal.

 

[prv]

in the UK about 30ft was the max that could be anodised there fore the joins in many masts inc.mine
on the continent they were /are able to anodise longer lengths

They still didn't always do it though - our Selden (Swedish) mast on a Swedish boat has a joint just below the gooseneck.

Pete

 

[FullCircle]

Aluminium welding will usually weaken the metal at the joint by nulling the heat treatment inherent in the extrusion. One of the reasons aircraft are rivetted and not welded.

 

[Concerto]

My Westerly Fulmar mast has a joint close to the deck, but this is the same on every Fulmar I have seen. So quite normal.

 

[Norman_E]

Mast extrusion only comes in certain lengths, for ease of transport. So any mast over about 12m will have a joint in it, and the riveted sleeve you describe is the standard method.

It's not a repair, it will be how it came from the spar manufacturer.

Pete

Mine is by Sparcraft, about 16.5 metres and has no joint. I see no reason why a joint should be a serious weakness, but I would be concerned if the joint was in a high stress position, for example just above the gooseneck.

 

[rjp]

If rivets in a mast worry you, don't ever look out of the window of a plane at the wing!