[Rhodes22-list] RE : Experimental Vang/Preventer

[David Culp]

Went over to the boat today and it looks like you could move the eye straps
forward on the rail approximately 15.5 inches and use the device with the
pop-top down.  The sail would be all the way out and using the same boom
bail position-the pull is angled back toward the mast.  This would alleviate
any load issues with the sheet.  With the pop-top up-when the boom goes
across the line is going to get caught in the top but will probably
be manageable.  Still to be determined is whether or not you will be able to
sail with the vang installed and tensioned, close-hauled with the top up.  I
was by myself and need another person to make that determination.

There doesn't look like any easy way to simulate this new setup to test it
on the water.  Since I just ordered a new genoa from Stan, I am going to
hold off installing any new eye straps until I see how the new sail is going
to lay against the rail.  I am dropping back from the 175% to about 130-135%
which is about a 12' length on the foot.  Once I get the sail, I may want to
install additional jib car track or a block in the same area instead of
straps to accommodate the new jib.

David




Date: Tue, 19 Jan 2010 18:11:41 -0600
From: David Culp <dculp at hsbtx.com>
Subject: [Rhodes22-list] RE : Experimental Vang/Preventer
To: rhodes22-list at rhodes22.org
Message-ID:
       <9ffb85a41001191611r259b92b3oc4250147888380f7 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Lee:

To answer your questions:  Yes, if the boom is forward of the strap it will
pull back towards the strap until it is above it.  When I was choosing where
to place the deck eye strap, I wanted to run the boom all the way to the
limit where the boom contacted the upper stay, mark the spot where the boom
crossed the rail and attach the eye there.  In that way, on a dead run with
the sail all the way out, the vang would pull directly down on the boom and
the sheet would carry its normal load.  It was quickly apparent that this
was not possible if one was trying to avoid a possible entanglement with the
pop-top in the raised position.  Also, I wanted to make sure that the line
could be cleated and released from the cam-lock easily and the shackle
quickly released.  I ended up installing the strap aft of the optimum
position due to these concerns.

What I was trying to caution about was letting the main all the way out on a
run and then using the vang to pull down on the boom.  It will pull the boom
down; but in the process because it is not underneath and lies on an angle
aft of the boom, it will begin to take the load off the sheet.  The more you
tension, the farther down it will pull, but it keeps pulling aft also-taking
on the sheet's load until the sheet is slack and the vang is carrying the
whole load.  This can be alleviated by tensioning the sheet to carry the
load at the boom's present position, but of course the sail can't be all the
way out.  The device and structure is certainly strong enough to carry the
load of the main during normal operation and I have sailed forward and
backwards using it alone during testing.  If you made a habit of it though,
I am afraid that a gust might come along and provide enough pull to break
something.  That was the reason for the caution.

When I am using the device, I let the main out to the point where it crosses
the strap and use it at that point.  The main is not fully out but close
enough.  The advantage is that the angle of the main diverts some of the
wind into the jib and keeps it filled when you are wing and wing.  The
disadvantage of course is that you have to sail closer to the leeward wind.

This being a work in progress... My thought now is to place a second set of
eye straps in the optimum position to be used when the pop-top is down.
 This would be a little farther forward of where the bimini eye straps are
now on my boat.  We could refer to this as the "performance" position.  I
usually drop the pop-top and lower the boom when the wind gets up or when I
want to go faster, hence the term "performance".  If I can figure out a way
to test it without having to drill any holes, I will see how it works in the
optimum position and report back.  Actually, the optimum position is
probably a little aft of full out because I don't like my main sail laying
full on the rigging.

To answer the second part:  The device is very effective when you are beam
and broad-reaching.  In fact, the first two pictures were taken on a beam
reach in about 11-12 knots of wind to show the before and after difference.
 On these points of sail, the boom will be over or aft of the strap and load
sharing with the sheet is not an issue.

Thanks for the kind words and questions, sorry for building the watch!

David

PS:  By the way, my caution statements are probably a little overdone.  When
you put something on the Internet, you never know who is reading it or their
experience level.  Concerning airplanes and boats, I tend to stay on the
conservative side of things because it can all go to "hell in a handcart"
pretty quickly sometimes if you don't.  Just a little common sense with this
thing and you are good to go.


Date: Tue, 19 Jan 2010 08:32:06 -0500
From: "KUHN, LELAND" <LKUHN at cnmc.org>
Subject: Re: [Rhodes22-list] Experimental Vang/Preventer
To: "The Rhodes 22 Email List" <rhodes22-list at rhodes22.org>
Message-ID:
      <BAEF334992594C47AD272D6B69E6C360022334F4 at EXCHVS02.cnmc.org>
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David,

Impressive set-up and very impressive website.  Your pictures and
explanations make it much clearer.

In one of your warning statements you mentioned:

IF YOU OVER-TIGHTEN THE DEVICE WHILE SAILING DOWNWIND, THE FULL LOAD OF
THE WIND IN THE MAIN SAIL WILL BE ON THE DEVICE AND ITS HARDWARE.  THIS
CAN BE AVOIDED BY NOT ALLOWING THE MAINSHEET TO LOSE ANY TENSION.  THE
PURPOSE OF THE DEVICE IS TO PULL THE BOOM DOWN-NOT TO BECOME THE SHEET.

This looks like it works great if the boom is over the deck eye strap,
but downwind wouldn't the vang pull the boom back towards the center of
the boat instead of down?

I'm more interested in using the vang on a reach and this may be just
what I need.

Thanks!

Lee
1986 Rhodes22  At Ease
Kent Island, MD


-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of David Culp
Sent: Tuesday, January 19, 2010 1:15 AM
To: rhodes22-list at rhodes22.org
Subject: [Rhodes22-list] Experimental Vang/Preventer

As promised, here is the link to the web page that describes the
vang/preventer that I built for my boat.

I am not recommending that anyone do this to their boat.  If you choose
to
build and install one of these, it is completely at your own risk.

My purpose in showing this to you is to pass along some information that
has
worked so far for me on my boat.  Perhaps someone with more ingenuity
then
myself will improve upon it and we will hear about it.  I think it was a
worthwhile project and worth the money.

Enjoy!

David

http://vang.davidculp.com