MERLIN ROCKET FORUM

Topic : Carbon mast "kit"

Following an unfortunate incident last weekend, I now have a Chipstow mast in four pieces - way beyond economic professional repair.  However, somebody with good DIY carbon skills might be able to do something with it (other than cut it up for a couple of Int Moth or Canoe booms).  Drop me an email for more details if interested.


Posted: 18/02/2007 17:56:43
By: Dave Lee
Is there a bit long enough for a merlin boom? or a kingpost?


Posted: 18/02/2007 20:23:56
By: Mags
Hi Dave, if a Chipstow I remember Alan repairing one of William Warrens masts that broke into 3 or more bits but if a Superspar not sure.
Bye for now


Posted: 18/02/2007 21:23:42
By: Barnsie
Chambulls' mast (originally William Warrens) has been broken twice since and repaired by Alan and it is as good if not better than new. Each repair cost less than a replacement Chipstow (but not less than a Superspars. The repairs cost me £100 excess each.


Posted: 19/02/2007 12:19:59
By: Alan F
Thanks all, but after discussions with Jacko and the insurance company, the mast is definitely a write off.  I have salvaged most of the fittings for re-use on it's replacement and been told I can dispose of the remains.  

The breaks are roughly 1/4, 1/2 and 3/4 height, plus the spreaders are both damaged. If no one wants it as a complete rebuild project, I'm sure the sections will find new careers -plenty of potential as king posts, but there is no single piece long enough for a Merlin boom.


Posted: 19/02/2007 13:49:36
By: Dave Lee
aparently The top makes a good cloths line prop..


Posted: 19/02/2007 15:33:11
By: OH for a faster boat
Can I 'bagsy' one kingpost please?


Posted: 19/02/2007 20:07:52
By: Mags
I'd be up for a king post for WAPB, I could replace the railway sleeper that some one used!


Posted: 19/02/2007 20:15:21
By: Alan F
What actually happened to the rig?


Posted: 19/02/2007 21:22:17
By: HAF
And are there any pictures of it happening!


Posted: 19/02/2007 21:42:37
By: RichardT
We were three sail reaching and got hit by a series of monster gusts, had to bear off loads, but it was seriously quick, great fun and all seemed under control.  I'm still not entirely sure what happened next, it was over in seconds, but the mast just seemed to fold up after bearing off into another gust.  No photos, but a close witness reckons our mast inverted, probably because the puller had come uncleated or had slipped.  The cleat didn't seem particularly worn, but has since been consigned to the skip anyway.  Luckily no other damage to hull, sails or crew - could have been a lot worse.


Posted: 19/02/2007 23:30:27
By: Dave Lee
Note carbon is not that strong in compression. Is a lightweight Jacko tube with pretty thin walls up to the job on its own???? If anyone does go down that route may be worth adding a wrap or two. Linton's boat use two posts to spread the load.


Posted: 20/02/2007 08:58:47
By: Ross
Dave - was it a bit like this?

http://www.noblemarine.co.uk/photos/mid_42.jpg

Posted: 20/02/2007 09:35:56
By: Mags
A caption competition possibility if ever I saw one!


Posted: 20/02/2007 10:37:10
By: Garry R
Hi Mags, yes, it was a lot like that!  No real drama, just a sudden loss of power :(


Posted: 20/02/2007 12:54:06
By: Dave Lee
Caption:-
When I said "de-power the rig" I ment!!!!


Posted: 20/02/2007 13:01:31
By: OH for a faster boat
If your after a caption competition how's about http://www.noblemarine.co.uk/photos/26.jpg


Posted: 20/02/2007 14:27:49
By: Stuart Bates
Shall we discuss this man to man?


Posted: 20/02/2007 14:51:30
By: Garry R
Just to make the link easier

http://www.noblemarine.co.uk/photos/26.jpg

Posted: 20/02/2007 14:52:07
By: Garry R
Sounds to me like one of the spreaders may have given up the ghost first.  That would result in a pretty mess like the one you describe!


Posted: 20/02/2007 15:05:29
By: deepy
Thats exactly how Will and I broke a chipstow into 3 pieces, we were at Rutland, Inlands a few years ago... and after noticing a broken spreader on the penultimate beat, we decided to be crazy and sail the run to the finish as it was, the second the spinnaker 'popped' a gunshot went off and we were surrounded by broken mast and sail - lesson to self, don't put the kite up in a F4 with only one spreader!


Posted: 20/02/2007 15:36:42
By: Rachel
me too.


Posted: 20/02/2007 16:12:55
By: CHAIRS
Mast has now gone!


Posted: 22/02/2007 18:28:34
By: Dave Lee
Interesting but little known fact is that when you break a long thin brittle object by bending it, it does usually break into 3 pieces rather than the more obvious 2 resulting from the first point of failure.


Posted: 23/02/2007 09:15:47
By: Rod & Jo
A BIT LIKE SPAGETTI! Get a long piece hold each end and twist breaks into three!!!


Posted: 23/02/2007 09:33:11
By: Richard Battey
by the way...... as informed by my 6 year old son!!!


Posted: 23/02/2007 09:34:11
By: Richard Battey
Spaghetti masts are all very well but the damp tends to get to them.  I much prefer carbon(ara).


Posted: 23/02/2007 09:50:56
By: Al Dente
at least it will now fit into a container!


Posted: 23/02/2007 13:49:16
By: john
Dad,

The study of axial compression buckling of isotropic cylinders has received much attention by various researchers over the years. It is commonly acknowledged that the presence of minute imperfections significantly reduces potential buckling loads in comparison with classical linear predictions. This approach, of including geometric imperfections, has been extended by a significant, yet fewer, number of researchers to composite cylindrical shells. As the current study shows, imperfections may not be the only major factor for the discrepancy between experimental and linear buckling loads. Flexural/twist anisotropy, present in most balanced, symmetric laminates with angle-ply layers, is shown to play a significant role in reducing buckling loads from those predicted by classical analysis. Indeed, the assumption of deflections in the form of a double sine series appears to be questionable for such laminates. A recently reported classically linear analysis that included the effects of flexural/twist coupling on buckling loads has been further developed to include the effects of extension/twist coupling. It is shown that buckling loads can be improved by making the laminate antisymmetric rather than symmetric, for the class of quasi-isotropic laminates, whilst retaining a spiral mode shape.


Posted: 23/02/2007 16:42:50
By: 6 Year Old Son
Good. That sorted that out then 
Any thing to add Deepy?


Posted: 23/02/2007 17:19:57
By: Shut Shed in Essex
Forget Spaghetti they can now use carrots for the fibres(some bright Professors in the midlands wanting to be green!)

Suppose it would be called CRP?

How long before we get carrot sticks to hold up your sails?


Posted: 23/02/2007 19:09:43
By: Roger Rabbit

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