On Sun, 11 May 2008 06:56:43 +1000, Herodotus
wrote:

Why is it that when I post to this newsgroup or write a hurriedly
email, I make so many bloody typos? When I type a report or such I
don't.
Damned annoying


FWIW - my experience

Nylon should not be used for underwater or near water bushings as it
has a tendancy to swell and thus tighten on the shaft.

I had the bottom and top bushing for my rudder made of HDPE and they
are still going strong - no swelling, no wear, no friction after 15
years in the water. It is the modern lignum vitae (sp?)

So far as I am concerned, the stuff is magic. You can drill it, saw
it, file and chisel it and can thus make a myriad of thing about the
boat. It is also cheap and readily available I find that the most
useful is an offcut slab of 20mm (0.75") which I was given from a
waste offcuts bin.

In addition to the inflatable I have a hard GRP 9' 6" dinghy which
breaks into two nesting halfs. In Australia I had to change the wooden
keel rubbing strake sometimes 6 monthly as nothing seemed to resist
the worms' boring activity, the dinghy being almost permanently in the
water. I tried Iron Bark and most other suggestions from the old
hands. I through bolted a length of HDPE to both halves and it is
still going stronge, sharp coral has no effect and even the barnacles
do not attach to it. Fantastic stuff.

The homeware shops and supermarkets sell breadboards which vary in
thickness from 2mm to about 12mm (0.5"). This stuff does not seem as
dense as the industrial HDPE I have but it comes in very useful as
washers, packers, shims, and anything else requiring a hard, cutable
inert and non-conductive material. I always carry a couple of
different sizes on board now.

regards
Peter