Hi Tim,

I just looked at the main panel layout on Lady K. and it struck me that
the main seams were not running as I expected. What's the story?

Cheers MC

Either:

can you be more specific? Which photo, what were you expecting?

Or:

If referring to "vertical" seams: Vertical of course was
traditional, until cross-cut demonstrated its superiority in the
old fabrics. With dacron, I am told that unless one is seeking
the absolutely last iota of aerodynamic efficiency, the direction
of the seaming makes almost no difference at all with modern
materials, modern seaming and heavy cloth (which Lady Kates main
certainly is!). As it's a gaff sail, and one is giving up a
degree of aerodynamic and pointing perfection for a larger area
lower down (lower heeling moment/area) and ease of rigging and
handling, and to boot it as a tree-trunk at the leading edge, the
sail was vertical seamed. (the authority for "I am told" was Ken
O'Brien). There are also supposed to be advantages in the event
of a tear, but I don't believe that.

Flying Tadpole's gaff sails and flying jib mit club were also
vertically cut, but her main staysail cross-cut.

Flying Tadpole

The navigator© wrote:

Hi Tim,

I just looked at the main panel layout on Lady K. and it struck me that
the main seams were not running as I expected. What's the story?

Cheers MC

Yes, I was expecting cross cut as you are using Dacron. BUT seaming is
still very important... e.g.

http://woodsdesignssailingcatamarans.com/rigs.htm

" In the old days of cotton gaff sails the cloth was weak and thus seams
ran vertically so, if they tore, the sail would not break in half. With
the advent of Dacron/Terylene, cross cut sails came into vogue partly
because these were (and still are) cheap to produce. More recently
computer sail design packages and laser cutters have made it easy for
sail lofts to make sails with more exotic panel layouts. "

Nevertheless i would have thought that with an inefficient rig, sail
shape would be even more critical and twist/draft control very
important. Even though Lady Kate would go very well downwind with any
(or even no) sail don't you want a bit more going to wind -or are all
your ports downwind...

Cheers MC


Flying Tadpole wrote:
Either:

can you be more specific? Which photo, what were you expecting?

Or:

If referring to "vertical" seams: Vertical of course was
traditional, until cross-cut demonstrated its superiority in the
old fabrics. With dacron, I am told that unless one is seeking
the absolutely last iota of aerodynamic efficiency, the direction
of the seaming makes almost no difference at all with modern
materials, modern seaming and heavy cloth (which Lady Kates main
certainly is!). As it's a gaff sail, and one is giving up a
degree of aerodynamic and pointing perfection for a larger area
lower down (lower heeling moment/area) and ease of rigging and
handling, and to boot it as a tree-trunk at the leading edge, the
sail was vertical seamed. (the authority for "I am told" was Ken
O'Brien). There are also supposed to be advantages in the event
of a tear, but I don't believe that.

Flying Tadpole's gaff sails and flying jib mit club were also
vertically cut, but her main staysail cross-cut.

Flying Tadpole

The navigator© wrote:

Hi Tim,

I just looked at the main panel layout on Lady K. and it struck me that
the main seams were not running as I expected. What's the story?

Cheers MC

Well, MC, I agree with all you say, as it was also what I
thought. However, in the case of Flying Tadpole II (Lady Kate
already had her suit) I took the advice of the sailmaker instead,
possibly because, as the sailmaker responsible for breaking the
hearts of the NYYC I felt he might know more than I, or possibly
because he learnt a few things from his uncle Conor that I
mightn't know in relation to cruising sails.

Mind you, I normally refuse to bow to authority unless it's
approaching celestial, but in this case I did not feel my own
experience and thoughts were defensible...

BTW, you appear to be still defining "efficiency" purely in terms
of extracting the maximum degree of weatherliness (70 degrees?).
Being naturally indolent, I tend to regard an efficient rig as
one which limits the demands on crew, machinery, rigging and
hull, while still providing a good degree of weatherliness (90
degrees).

Flying Tadpole

The navigator© wrote:

Yes, I was expecting cross cut as you are using Dacron. BUT seaming is
still very important... e.g.

http://woodsdesignssailingcatamarans.com/rigs.htm

" In the old days of cotton gaff sails the cloth was weak and thus seams
ran vertically so, if they tore, the sail would not break in half. With
the advent of Dacron/Terylene, cross cut sails came into vogue partly
because these were (and still are) cheap to produce. More recently
computer sail design packages and laser cutters have made it easy for
sail lofts to make sails with more exotic panel layouts. "

Nevertheless i would have thought that with an inefficient rig, sail
shape would be even more critical and twist/draft control very
important. Even though Lady Kate would go very well downwind with any
(or even no) sail don't you want a bit more going to wind -or are all
your ports downwind...

Cheers MC

Flying Tadpole wrote:
Either:

can you be more specific? Which photo, what were you expecting?

Or:

If referring to "vertical" seams: Vertical of course was
traditional, until cross-cut demonstrated its superiority in the
old fabrics. With dacron, I am told that unless one is seeking
the absolutely last iota of aerodynamic efficiency, the direction
of the seaming makes almost no difference at all with modern
materials, modern seaming and heavy cloth (which Lady Kates main
certainly is!). As it's a gaff sail, and one is giving up a
degree of aerodynamic and pointing perfection for a larger area
lower down (lower heeling moment/area) and ease of rigging and
handling, and to boot it as a tree-trunk at the leading edge, the
sail was vertical seamed. (the authority for "I am told" was Ken
O'Brien). There are also supposed to be advantages in the event
of a tear, but I don't believe that.

Flying Tadpole's gaff sails and flying jib mit club were also
vertically cut, but her main staysail cross-cut.

Flying Tadpole

The navigator© wrote:

Hi Tim,

I just looked at the main panel layout on Lady K. and it struck me that
the main seams were not running as I expected. What's the story?

Cheers MC