[Public-List] Gooseneck track repair and replacement

[Jonathan Bresler]

John,

Thank you very much!
Good to know that this is addressed and I need not concern myself with it.
The 1/4-20 screws and threaded holes in the mast with three full threads
engaged
will be quite strong as you note. Fastenal has a nice write up threads in
bolts
(presumably screws as well) that shows that the percentage of load borne by
each
thread of a fastener. (https://www.fastenal.com/en/78/screw-thread-design
at the bottom
of the page)

Jonathan



On Thu, Jul 30, 2020 at 3:24 PM John Maliszewski <vzjrmalis at gmail.com>
wrote:

> Jonathan, you should be happy that this particular problem on your boat
> (#262) had been solved a long time ago. The piece of teak or whatever
> Whitby used as the track spacer had been replaced with a piece of naval
> brass machined to size. This peculiar Whitby construction formed a less
> expensive "T" and served its purpose for many years. In this case, after
> creating a brass spacer machined to size with clearance holes, I simply
> shifted the hole pattern by half of the pitch of the existing holes on the
> mast, and drilled and tapped a new set of mounting holes. The mast cross
> section thickness of the flat section of the mast is .167 inches and the
> inside flat measures 1.700 inches. ( I will ask George D. to publish a
> dimensioned cross section drawing of the mast on the A30 website.)
> Given 1/4 -20 thread screws that should give a full three
> treads engagement in the flat portion of the mast. Introducing a new backup
> plate is more trouble than it is worth.
> The original problem is that the wooden spacer deteriorates over time and
> allows the rail portion of the "T" to move and even perhaps become
> completely loose. Loose state of this engagement point reduces considerably
> the strength of the gooseneck assembly mounting, especially during the
> accidental jibes, and leads to broken screws or compromised treads in the
> mounting holes.
>
> John Maliszewski
>
>
>

-- 
Jonathan M Bresler
S/V Constance Alberg 30 #262
Annapolis/Eastport MD