Search found 503 matches

by Bill Roberts
August 27th, 2016, 6:17 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

gahamby, if the sail is in good shape, stay with it. Maybe it spent several years not used. Fresh water sailing is much easier on sails than salt water sailing. At your weight don't sit in the back of the boat and make it squat. Keep the knuckle of the bow underwater and you will have the boat trimm...
by Bill Roberts
August 27th, 2016, 12:18 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

The gaff batten does need to be a little stiffer than any of the other battens in the sail. If you have Tom fix your sail, he can supply you with a correct top/gaff batten at that time. Was your sail built in 1984? If so, you might need a new one.
by Bill Roberts
August 26th, 2016, 4:19 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

Yes, make the square top anywhere from 25% to 40% as wide as the foot of the sail.
The factory is using 40%. No Change to the foot.
Go for it.

If you don't have an experienced sailmaker with square top sails in your area,
maybe Tom Haberman could do it for you.
by Bill Roberts
August 26th, 2016, 7:04 am
Forum: Technical Forum
Topic: Spinnaker Theory
Replies: 14
Views: 14685

Re: Spinnaker Theory

Kevin, The spinnaker on your boat when trimmed and sailed properly, it is acting like a big Genoa sail. The airflow will be across the sail. You need luff taletells to see when the flow is attached and flowing across the sail just like on your jib. The spinnaker and main are trimmed in tight. Do not...
by Bill Roberts
August 25th, 2016, 7:42 pm
Forum: General Discussion
Topic: Generic Sails
Replies: 4
Views: 6093

Re: Generic Sails

Bruiser What I am going to tell you applies to any jib, factory made or otherwise. I use the jib sheet tension to set the overall shape of the jib. I use the clew corner adjustment plate to set the jib leech position and leech shape when looking up the leech. When you connect the jib sheets to the h...
by Bill Roberts
August 25th, 2016, 2:16 pm
Forum: Technical Forum
Topic: Spinnaker Theory
Replies: 14
Views: 14685

Re: Spinnaker Theory

Kevin, no you are not trying to stall the spinnaker. When the hull flies TOO HIGH with spin, bare off a little. Why? When you bare off,the resultant force from the rig is aimed more forward. The boat has much more forward stability, 20ft long, than it has sideways stability, 12ft wide. So, bare off ...
by Bill Roberts
August 25th, 2016, 1:01 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

gahamby, yes your dacron SC !5 mainsail can be made into a square top by adding width at the top. Your sailmaker needs to know what he is doing. Some of the load traveling up the leech needs to continue up to the square top corner and then come across the top to the mast. The upper leech should be t...
by Bill Roberts
August 25th, 2016, 8:34 am
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

havliii, Why would one go to all that trouble and expense to cut down a sail and rig just to break even. To get a new reinforced head put on a mainsail would cost a few hundred dollars. Option 2, make a square top out of your 30ft pin head sail and go faster. This is what the sailing world is doing....
by Bill Roberts
August 24th, 2016, 9:33 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

havliii, In scientific testing, one parameter at a time is varied. In the span effectiveness tests where the taper ratio was varied over a wide range, SAIL AREA or WING AREA was held constant while tip chord to root chord ratio was varied. If area had been allowed to vary at the same time, no defini...
by Bill Roberts
August 24th, 2016, 6:15 pm
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

HI Kevin, I was advised that locked was the best way to handle this paper. Two more are coming thanks to Matt Haberman. A wingtip plate might help reduce the wing tip vortex, leakage over the tip. A correctly built wing/sail "tip" should have a slight upward slope to it toward the trailing...
by Bill Roberts
August 24th, 2016, 11:38 am
Forum: Technical Forum
Topic: Square Top vs Pin Head
Replies: 25
Views: 24790

Re: Square Top vs Pin Head

Bruiser, our primary objective is to get the most thrust per square foot of sail area out of the sail. This will occur at a sail twist that matches the twist in the relative wind direction from the foot of the sail to the head of the sail. If we increase the twist more than than that, the spanwise f...
by Bill Roberts
August 23rd, 2016, 4:41 pm
Forum: Technical Forum
Topic: SC19 Rework
Replies: 59
Views: 57480

Re: SC19 Rework

Bruiser, thanks for your comment. When we go to races, occasionally we see an old SC that has been restored. There was one at the Mug Race for the last two years. Why don't we see any NACRAs or Hobies being restored? Answer: In the field of fiberglass boat building products there are three levels of...
by Bill Roberts
August 23rd, 2016, 11:05 am
Forum: General Discussion
Topic: More on leeway and sail trim (tom's video)
Replies: 7
Views: 7710

Re: More on leeway and sail trim (tom's video)

Thanks T. Peterson, "ride'm cowboy'!
That technique is about 40 years old.
How did it get Lost?
by Bill Roberts
August 22nd, 2016, 3:42 pm
Forum: Technical Forum
Topic: SC19 Rework
Replies: 59
Views: 57480

Re: SC19 Rework

I see very much hard work to repair this boat/these hulls. Thanks for saving their lives.
Some one must have paid you to take this boat.
by Bill Roberts
August 21st, 2016, 8:50 pm
Forum: General Discussion
Topic: New Sails - Help, Tom!!??
Replies: 10
Views: 9410

Re: New Sails - Help, Tom!!??

Dan, Relative to your comment about Tom wanting you to by sails that will uphold the SC/ARC reputation. NUMBER ONE PRIORITY, "TOM WANTS YOU TO BE PLEASED WITH THE NEW SAIL". Tom has spent hours on the phone trying to straighten out sail messes people have gotten into when they bought sails...