[Public-list] Chainplate knees and mast pad

[George Dinwiddie]

Eliminating the knees seems an overreaction, to me.  Using plywood, even
marine grade, for an area where you plan to through-bolt to the outside
(particularly in a place that will, at time, be underwater), seems
risky, also.  It also sounds difficult, as there are bulkheads in the
way.

Typical chainplate knee jobs involve

 * Filling any space between the knee and the deck.  On some boats,
   Whitby didn't fit these very well.  Leverage against the deck adds
   a lot of strength.

 * Extending the length of the knees to provide a more secure attachment
   to the hull.  Some people remove the knees and replace them with new
   ones, but if the originals are in good shape, I like Towney's
   solution of adding additional knees below the originals and
   connecting them with straps.

  - George


On Thu, Jul 29, 2004 at 05:42:17PM +0100, Peter Amos wrote:
> Also I have always been concerned about the chainplate knees.Compared
> to those I have seen on other boats of a similar size they appear
> lightweight and not well finished.Although I have never heard of them
> being a problem,except the 1/4 bolts,while the mast is down it would be
> a good opportunity to do something about them.I have in mind to remove
> them,and after preparation add a couple of layers of heavy mat to the
> hull along the length between the lowers.Then add three strips of 1/4"
> marine ply over the same area so there is a thickness of 3/4".Finish up
> by fixing new sturdier chainplates inside bolted through the hull from
> the outside with 5/16" bolts.

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