Masthead Fixing

[aitchem]

Hi,
Is it normal to fix the masthead with a bent bolt in the mast wall, then fixed vertically with a nut.?
I know the bolt isn't loaded in use, but, a BENT bolt, worked past it's yield.?

I am looking for a better arrangement.

thanks
Howard

 

[merlin3688]

Z Spars used to fit the head box this way and still probably do! The loads are all down and all the bolt is doing is holding the box in place. Many years ago the box was welded in by some companies, this was ok until the box got damaged and needed replacing, the bolt in box can be replaced easily as long as the box is still made.

 

[prv]

Is it normal to fix the masthead with a bent bolt in the mast wall, then fixed vertically with a nut.?

That's how my Selden unit is fitted.

As Merlin says, all the rigging loads are pulling the masthead unit downwards into the mast, so it would probably stay put even without the bolts.

You must be that very rare boat-owner who has reached the end of his job list, if you have time spare to start second-guessing the spar builder

Pete

 

[aitchem]

Ok Ok but...........
If I offered a bent bolt as a solution at work, I would be escorted off the premises.

 

[sailorman]

Ok Ok but...........
If I offered a bent bolt as a solution at work, I would be escorted off the premises.

the bolt is only there to hold the cap / crane in place, the shrouds exert a downward pull.
if you have a real mast its all welded & tapered to look nice

 

[rob2]

You could make a matching part from rod, bent to shape by a blackmith so that it retains its full strength - but a cable tie is strong enough to do the job. I suspect the bent bolt was used as intentional overkill as new masts might be shipped by all means worldwide. I like it as I can easly remove the crane when the mast is down to access the wiring conduits and inspect the halyards in situ - or even take it home to replace the sheaves.

Rob.

 

[vyv_cox]

A bit of plastic deformation, if done properly, increases the strength of the component. Bottle screws are a good example but many rigging components are cold pressed for strength. The rigging wire is cold drawn, for the same reason.

 

[30boat]

I agree it's not a pretty engineering solution but it works.My old Kemp mast had that arrangement and I found that the heads on the bolts were only lightly welded on nuts.The loads were all vertical and the mast stood for 30 years without problems.

 

[Stemar]

A friend has a similar arrangement on his Starlight 35.

I did wonder about it when I was out with him once and conditions deteriorated from "Feffin 'orrible" to "I wish I'd taken up golf instead", but the mast survived. He recently returned from an Atlantic circuit and, while he did break a couple of crew (not his fault!), he didn't manage to break the mast.

It did have the advantage that removing the head to inspect everything in there and run some new wiring down the mast was a doddle.

 

[DanTribe]

Selden Mast catalogue page 21 part nr 169-001 to 005 depending on diameter.
http://www.seldenmast.com/flipbook/default.cfm?pubID=97226AAE-DCFD-0EDE-3FED987AD9A0261E

 

[vyv_cox]

Here is mine. Unchanged since 1984, complete with bent bolts. The cap has been off once as far as I know.