Author Topic: Mast step - sleepless night  (Read 17842 times)

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roland_trim

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Mast step - sleepless night
« on: May 18, 2009, 10:53:42 AM »
Last night I bogged in the mast step. I added some unis to take the load into the bulkheads and then some weave over the lot.

Then I failed to sleep.

When we add the deck on we will add another fillet at the bottom of the mast step/deck intersection. What are the chances of this being a stiffer load path and the core simply crushing and then failing the lot?

The mast stump is a tube, the tube is cut over the intersection of the three bulkheads (4th tail will follow soon from interesection to CB pad) Photos on:
http://www.sailingsource.com/cherub/test/doku.php/tech/bmg/20090518thats_magik

Any comments appreicated.

Offline ross_burkin

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Re: Mast step - sleepless night
« Reply #1 on: May 18, 2009, 12:28:50 PM »
I'm still a bit tired after a heavy weekend so bare with me. Are you worried that instead of the core transfering load from the deck to the hull skin vertically, the fillet between the deck and the top of the bulkhead will just crush the foam downwards?

I'm sure yours is not not going to fail as badly as mine did...
« Last Edit: May 18, 2009, 12:31:39 PM by ross_burkin »
2675 Fuzzy Logic  97/05 rules

Serious plannage in the works...

Offline neal_gibson

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Re: Mast step - sleepless night
« Reply #2 on: May 18, 2009, 12:44:58 PM »
good effort ross it it go right through the hull as well hope you get it fixed though
2644 Suicide Blonde

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Damage count so far this season
1) RS Feva mast easy
2) Cherub Main Fixed
3) VW BORA Gone forever bugger
4) One cherub boom Debi does ass damage fixed now.

Offline JimC

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Re: Mast step - sleepless night
« Reply #3 on: May 18, 2009, 08:37:29 PM »
If've done two stumps like that, (one Cherub, one IC) and never had a moment's worry.  It would require something truly overwhelming to detach it from those three bulkheads with all that glue area in shear, in which case any failure to the core under the step would be the least of your problems...
« Last Edit: May 19, 2009, 04:03:20 PM by JimC »

roland_trim

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Re: Mast step - sleepless night
« Reply #4 on: May 19, 2009, 09:57:55 AM »
Thanks Jim.

Offline phil_kirk

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Re: Mast step - sleepless night
« Reply #5 on: May 19, 2009, 12:18:13 PM »
I have done similar to you Roland. Copying the great work of Andy P on the first E-5.  That appears to work ok.