On 23 Oct 2004 00:40:24 -0700,
(peterMelbourneAustralia) wrote:

Thanks for your input, all very scientific. Having the mast tested
using weights has some logic to it.

The boat is a proa, a multihull. The side says (there is only 1) is 4m
from the mast. Mast is 6m high. Righting moment could be rather high
as I was hoping for 50kg of water ballast in teh outrigger at 4m to
windward. 50L water ballast tank need not be full I guess.

The mast comes from a professional mast/spar maker.

The boat is a proa. Main hull is 23 long, 2 ft wide, boat weigh
unladen is less than 200kg. Not intending to break speed records.

I was hoping to do a comparison with a boat like a Hobie 14 cat. I
wonder what their mast dimsnsions woudl be, cannot recall the mast
section details of the windrush 12 cat that I used to sail, for some
reason never got around to measuring it. Feel that a hobie 14 - 12 has
simialr sail area/righting moment, is stayed out wide as per proa. So
what is good for that would be good for me.

N. Peter Evans


Here's another way to compare and contrast your selection with
comparable masts. Look at the sections shown by this aluminum mast
company - [Dwyer Mast Co]

http://www.dwyermast.com/families.asp?cat1ID=20&cat1Name=Masts

Notice that the lighter sections come in several shortish lengths and
the beefier sections come in correspondingly longer lengths.

This gives you an idea of the preferred section for a given length.
A proa will be stiffer in roll than a regular rig, so you would want
to compare a section where your desired length is the shorter of the
mast length offerings for a given section.

Short masts (as fitted to dinghies) are not typically let out in
stiff blows, so this is another factor to bear in mind.

Still, this exercise should reinforce your judgment.
I am disappointed that the other respondents in general gave you
every suggestion short of anything actually helpful.

I have never seen so many different way of saying,
"Ooh, mast section selection is awfully difficult and mathematical,
and far too difficult for a regular person to consider...."

I hope you will realise sooner or later, that the basis of many mast
selections is in fact "cut and try" and "It worked on that and the
other so it should be OK on this..."

Regards

Brian W

On Mon, 25 Oct 2004 01:55:38 GMT, Brian Whatcott
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

I have never seen so many different way of saying,
"Ooh, mast section selection is awfully difficult and mathematical,
and far too difficult for a regular person to consider...."


Noooo...."Based on the very limited information given, and an admitted
lack of knowledge about proas, which are completely different from any
other craft in build stability, and sailing methods, I will not form
an opinion about the corretc mast"

The guy is basing it on a 14" cat. Not a proa. He is also looking a
cruising, unlike a 14' cat. 14' cats are rarely sailed in 45 knot
winds, on a cruiser you may have no choice.


I hope you will realise sooner or later, that the basis of many mast
selections is in fact "cut and try" and "It worked on that and the
other so it should be OK on this..."

As you say "Cut and try". But don't ask me to say you are right based
on bugger all.

************************************************** ***
Have you noticed that people always run from what
they _need_ toward what they want?????

On Mon, 25 Oct 2004 12:54:59 +0800, Old Nick
wrote:
...."Based on the very limited information given, and an admitted
lack of knowledge about proas, which are completely different from any
other craft in build stability, and sailing methods, I will not form
an opinion about the corretc mast"

When asked for help, no matter how partial or sketchy the background
offered, if you cannot form an opinion, wouldn't it be better to
forebear from posting on the topic?

Brian W