On Sun, 12 Jun 2005 15:10:40 -0400, "Glenn Ashmore"
wrote:

I am not sure you exactly grasp the forces that act on boats at sea.

I am aware of "the forces that (can) act on boats at sea". I readily
can not give you the ref. for the following, but am willing to accept
them as reasonable:

It was stated that about 93% of the time the winds are between 13-17
knots and for the remaining 7% of the time - 97% of that time they are
between 17-21 knots.

Its not the wind (for the most part) that does damage it the waves, as
you suggest.

I can not reasonably recall the force of a breaking wave on the deck
of a boat but I do recall I was amazed at figure of that force.

I do like the "cork" theory of a boat though...

About
the only thing that would make ABS pipe strong enough to stand up as a
Bimini frame would be a stainless tube on the outside. :-) Same is true
for that copper tube support on your windvane.

The copper tube support that "Walt" designed is interesting, but when
compared to the commercial vanes it is rather "light". I do believe
he said it survived 20 knot situations.

I have researched virtually all the sailing homebrew material
available:
- a PVC furling rig
-homemade furling
-homemade gennys, wind, water, fuel
-wind vanes
-polytarp sails
-stitch and glue techniques
-seahoods
-bimini's and dodgers
-PVC wisker poll
- all sorts of ingenius ideas and techniques, I read once that someone
called sailing a "thinking mans sport"...

I define intelligents as someone who see's something other than what
it is...ie a round disk is a dish, is a wheel, is a pully, is a
gear....a rather simple example but thats the idea.

Being smart I figure means that you dont have to work hard at learning
things. Me I am a limited person....."stupidity is unlimited, genius
is limited" :}

One good quartering wave and
it will collapse against the transom. Most of the failures of commercial
stering vanes are in the stainless support structure.

Personally I dont have any experience of the failure of wind vanes.
But from the numerous crusing logs I have read most of the failures
have been the vane "sail" and the associated rudder, as well as
various fasteners. Failure of the support structure has been less
common from my readings. YMMV.

I have seen the origin designs of wind vanes, I think one version was
of a friend of the Pardeys...actually earlier...

Here is the URL link:
http://www.freehandsteering.com/Windvane%20Story.htm
http://www.freehandsteering.com/Image.htm

http://www.geocities.com/Yosemite/Fo...ist/fhist.html
"World War II hero and wind-vane self-steering innovator Blondie
Hasler participated in a highly modified Folkboat named Jester. "

"Jester incorporated many innovations. Blondie Hasler was a pioneer in
the development of pendulum servo windvane self-steering gear. Jester
was steered from below decks via a whipstaff. All sail handling could
be performed from a central hatch without going on deck."

Other links:
http://www.freehandsteering.com/
http://www.hydrovane.com/


316 Stainless has a
tensile strength of about 580 Mpa while hard drawn copper tube is under 200
Mpa. Heating to assemble it will soften it even further so soldered copper
tube doesn't stand a chance.

Thanks for the specs......

Actually I think the weakest points in an ABS material would be where
there are fittings like 90's etc. and the point at which the rig is
fastened to the boat. (1 1/4" abs)

This is just an "idea" with the thought of getting opinions. Yes,
stainless tubing would be the way to go...$$$ and less workable as a
homebrew project. I like the ideas of these sort of boat
projects...not always the best answer but possibly a starting point.

I am certain that by building your own boat you know what I mean.


Same with the Bimini. The bending forces in tubing is all in the outer
fiber. Nothing you put inside (other than a steel tube) that will help
much. One good blow or an accidental steadying grab and it will be headed
for the recycling yard.

Humm...I am not so certain...but anything is possible although less
probable....

Fairwinds and calm seas.....

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Mic" wrote in message
...
I am looking for any suggestions for a material that can be used to
fill the void in a PVC or ABS tubing, if and when used as tubing for a
bimini or the like. What size would you recommend?

Some thoughts include: epoxy, liquid foam, (cement -concrete???).....

Also what about using braided cable as a sort of rebar in the tubing
before filling tubing void?

Also what about using 3/4 or 1 inch copper tubing for a bimini or
dodger (plumbing supplies) with same tech. as above.


Thanks in advance.