A Sail Trim Question

[Robert Crooks]

Last Friday was the perfect day to check out the effect my new Max prop two
blade has on JADE’s sailing performance; 8-10 knots of fairly steady north
easterly wind, slack tide and absolutely dead flat water on the West River.
 
Boat seemed to sail just fine but the whole thing confirmed what I had been
suspecting for the last two years since I bought it (i.e. even before I put
the new prop on).  When close hauled, even though it feels like it is
sailing just fine, the fact of the matter is that, on either tack, it always
had weather helm equivalent to exactly one eighth of a turn on the wheel,
regardless of what I did with the choker and/or the mainsheet.  I could lock
the helm off and it would maintain its course for long periods and it
definitely felt like it was right in the groove but I would have thought
that it should be possible to maintain a course with a lot less helm.

I have studied Bott's Thots in great detail regarding this matter, even
chanting and offering incantations, but so far, have found no obvious
explanation. Is there something I am missing here or should I take this as
a message that my 23 year old sail, which has a pot belly almost as big as
my own, might be approaching its use-by date?
 
  
Rob Crooks
JADE  26U  198  1986
Galesville MD   Hartge Yacht Yard
Chesapeake Fleet
 
1800 Lamont St. NW
Washington DC 20010
Home Ph: (202) 232 2713
Cell Ph: (301) 509 9257
E-mail: robert...@verizon.net

[Ed Botterell]

I happen to be sitting here, so before the real experts get their 2 bits in, here is my thot.

 

If you pushed or pulled the boat, any boat, at a speed consistant with that which an 8-10 knot breeze would produce under sail, the general effect would be no helm at all.  But as soon as you use the sail to propel the boat, the boat must heel, and that is what produces the weather helm.

 

Now you could argue details, but the reason the boat can sail by itself is that it does heel under sail.  With the locked wheel, as the wind increases a bit, the boat heels a bit more and then seeks to find the original heel by heading up. Once it reduces the heel to that which is offset by the locked position of rudder angle, it is happy again and sails straight.   Visa versa with a bit of decrease in wind velocity.  It is the weather helm generated by the heel that allows you to lock the wheel with 1/8 turn you say you had, and have the boat sail itself.

 

As the boat heels to starboard, it wants to turn to port; the more heel, the more urge to turn to port, and the more weather helm requiring more rudder angle to keep a straight course.  It's all in the hydrodynamics .

 

Sounds to me it's working just as it should.  You would get less heel with a new sail under the same conditions, with less weather helm and a little more speed.

 

We'll see what the real experts say

 

a genuine botts thot

[Robert Crooks]

Thanks for the explanation, Ed. I’ll feel a lot less anxious about that bit
of weather helm from now on.

I’ve cut and pasted your explanation into the “Notes” section of my Bott’s
Thots (or where the “Notes” section would be if it had a “Notes” section).

Rob

[Joe Thompson]

strongly agree. Don't change anything. Your setup is perfect. If you had
zero helm in those conditions I would want you to rake more or go to a
tighter-leech setup (sheet tension) to get some helm. The small angle of
the rudder is helping you gain ground to weather. Perfect.

Joe Thompson NS26U "Cato"

"It's not a race, it's a GROUP SAIL"

[Brooks Bridges]

If you really want a feel for what Sir Botts and John are saying, take a small dinghy out sailing on a non-hiking out day.  Sail it with a small amount of heel - boat feels alive - easy to get to find the windward groove.  Shift weight to reduce heel to zero and the tiller will go dead  - no joy - very difficult to keep it in the windward groove.  Surprisingly dramatic changes. Brooks Bridges SOLITUDE 30U 290 Cambridge, MD --- On Tue, 5/12/09, Robert Crooks <robert...@VERIZON.NET> wrote:

From: Robert Crooks <robert...@VERIZON.NET> Subject: A Sail Trim Question

[Jack Lombard]

Robert,     Try easying the sheet. in the conditions you sailed in and then unlock the wheel, ease slowly till the helm approaches neutral.   Remember.a 23 year old sail, depending on how much use it 's had, more than likely has had the draft moved back which results in more heel, thus more helm, and loss of speed....Jack Lombard "Bearcat".

----- Original Message -----
From: "Robert Crooks" <robert...@VERIZON.NET>
To: NONS...@LISTSERV.AOL.COM

Sent: Tuesday, May 12, 2009 3:08:42 PM GMT -05:00 US/Canada Eastern
Subject: A Sail Trim Question

[Allen S. Ames]

In my humble opinion, a weather helm equal to one-eighth of a turn on the wheel is a healthy one and is similar to what you would get on a well-trimmed sloop. 

 

Just be sure that you are trimmed properly and are heading as high as possible.  In a good breeze this might mean a very slight shiver or bubble in the belly of the sail – keep an eye on the speedo or GPS as you slowly head up.  There is a strong tendency to sail the Nonsuch much too hard on all points of sail.  Our old saw was to treat the sail as if it were a #1 Genoa jib, not a mainsail.

 

Botts, where are you?

 

Allen Ames

[Ed Botterell]

Ames; Where are YOU?? 

 

I responded to that request for guidance so long ago that my Alzheimers requests permission to not recall it.

 

Fortunately for you, my e-mails hang around, and you will note below that my thots coincided precisely with yours. But I'm more verbose.

 

Indeed, this is your lucky day.

 

Thank you for bringing you to mind.

 

Your (old) friend botts

 

---

April 12 at 4:01 (PM) I wrote to Mr.Crooks and the list......

 

I happen to be sitting here, so before the real experts get their 2 bits in, here is my thot.

 

If you pushed or pulled the boat, any boat, at a speed consistant with that which an 8-10 knot breeze would produce under sail, the general effect would be no helm at all.  But as soon as you use the sail to propel the boat, the boat must heel, and that is what produces the weather helm.

 

Now you could argue details, but the reason the boat can sail by itself is that it does heel under sail.  With the locked wheel, as the wind increases a bit, the boat heels a bit more and then seeks to find the original heel by heading up. Once it reduces the heel to that which is offset by the locked position of rudder angle, it is happy again and sails straight.   Visa versa with a bit of decrease in wind velocity.  It is the weather helm generated by the heel that allows you to lock the wheel with 1/8 turn you say you had, and have the boat sail itself.

 

As the boat heels to starboard, it wants to turn to port; the more heel, the more urge to turn to port, and the more weather helm requiring more rudder angle to keep a straight course.  It's all in the hydrodynamics .

 

Sounds to me it's working just as it should.  You would get less heel with a new sail under the same conditions, with less weather helm and a little more speed.

 

We'll see what the real experts say

 

a genuine botts thot

 

 

 

----- Original Message -----

From: Allen S. Ames

To: NONS...@LISTSERV.AOL.COM

Sent: Monday, May 18, 2009 9:07 AM

Subject: Re: A Sail Trim Question

[Barbara Melanson]

Over the winter I had multiple coats of Cetol stripped from my cockpit grate. The resulting teak is a combination of gray and reddish brown. What is the best way to care for this teak? How do I avoid it turning black with mildew or drying out too much?
 
Thank you for any advice.
 
Barbara Melanson
Gimlet II  33  14
Groton Long Point, CT
 

[Rob Powers]

You might try the Interlux one part teak cleaner. It restores the natural colour w/o sanding. After that just clean with mild soap or salt water. Don’t use a stiff brush, it may remove the softer parts of the teak leaving grooves.

 

Rob Powers Respite, 26C