Overlapping versus Blade headsails which is quicker ? - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > Out There > Racing
 Not a Member? 


Like Tree3Likes
Reply
 
LinkBack Thread Tools
  #11  
Old 05-23-2012
SchockT's Avatar
Senior Member
 
Join Date: May 2012
Location: North Vancouver, BC
Posts: 1,425
Thanks: 1
Thanked 27 Times in 25 Posts
Rep Power: 3
SchockT is on a distinguished road
Re: Overlapping versus Blade headsails which is quicker ?

Most racers will go with the most sail area they can carry and still maintain optimum heel angles and helm balance. The potentially tighter sheeting angle that can be gained with the blade is probably not a huge consideration, certainly not if it means you are under-powered in the lulls. I would certainly rather be depowering in the gusts than wishing I had more power in the lulls! That goes double if there are waves. Of course that is also assuming that both sails are in good condition and have decent shape!
Reply With Quote Share with Facebook
  #12  
Old 05-23-2012
Jeff_H's Avatar
Moderator
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,582
Thanks: 5
Thanked 95 Times in 71 Posts
Rep Power: 10
Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about
Re: Overlapping versus Blade headsails which is quicker ?

When you are talking about modern boats, they are typically fractionally rigged and designed with very large SA/D's with the intent that they will not be sailed with overlapping headsails. The thinking is that this sail plan is more efficient that way and much easier to handle. These rigs are much easier to power up and down (not the same as reefing) and compared with older designs these new boats have a huge amount of stability as relative to thier drag and so can carry this large SA/D in a very wide wind range.

If there is a short coming to this rig proportion, it is at very deep reaching angles and dead runs in light to moderate wind, where nothing beats raw sail area. In racing, this is completely offset by the use of assymetric deep reaching spinnakers and to a lesser extent, code zeros. Cruising with these boats, you almost never head dead downwind in light to moderate conditions and so can usually get by with reaching at hotter reaching angles and building your own apparent wind when it does not make sense to fly a chute.

The problem with the Hanses is that they are surprisingly high drag for a modern design, and do not have all that much standing sail area. They are also limited by their next to useless self-tacking set up which means that the normal jib is very small (90% or so), and does not set as well as might be ideal. It sounds like you have a custom set up which may let you use a 105-109% headsail.

The hot ticket if you are having a custom 'all-purpose' made is to have it made from lighter weight, high modulus- low stretch material, cut slightly full for slightly higher headstay sag, and with a lot of roach and furlable battens. The key is to have the sail maker take physical measurements on ypur boat to maximize the luff, roach and foot length. The design should assume that the jib car is placed as far aft as possible but not so far aft that sheet hits the shroud when power reaching.

If done properly this results in a sail with excellent performance across an extremely wide wind range. The light fabric, larger area of the roach, and fuller shape works well at the light end of the range. As the breeze picks up, the backtstay adjuster can be used to remove headstay sag and flatten the sail. The low stretch fabric allows the sail to be carried well into heavier conditions, increasing backstay tension to further flatten the sails and then reefing at the top of the wind range.

I had Quantum build a sail like that for my boat and it has a range from 3 knots well up into the mid to high 20 knot range. Its 3 years old and basically looks like new.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay and part-time purveyor of marine supplies

Last edited by Jeff_H; 05-23-2012 at 11:50 AM.
Reply With Quote Share with Facebook
  #13  
Old 05-24-2012
Senior Member
 
Join Date: Feb 2012
Location: New Orleans Louisiana
Posts: 1,964
Thanks: 6
Thanked 43 Times in 41 Posts
Rep Power: 3
Stumble is on a distinguished road
Re: Overlapping versus Blade headsails which is quicker ?

As mentioned above it really depends on the boat.

But typically a #2 (say 115-135) is the worst possible sail for any conditions. If you coukd ignore the spreaders and stay you could get a decent sheeting angle on them, but obviously you can't. This requires you to move the lead well outboard of the ideal sheeting angle. A 155 by comparison while having to go just as far outboard, also gets to come much further aft. So the angle between the centerline of the boat, and the line made from the tack to the clew is much smaller.

This is why most racing boats go from a 155 to the largest inside overlapping sail they can fly (typically a 115 or so). Not because reducing sail area isn't desirable, but because when you reduce area you also increase the sheet angle to such a point that it kills your pointing ability. And for most boats it is faster to be slightly over powered than to have to give up the pointing ability. Though there are boats this isn't true on, particularly very narrow for the leingth boats like an Olson 30, or Hobie 33.
Reply With Quote Share with Facebook
  #14  
Old 05-25-2012
SchockT's Avatar
Senior Member
 
Join Date: May 2012
Location: North Vancouver, BC
Posts: 1,425
Thanks: 1
Thanked 27 Times in 25 Posts
Rep Power: 3
SchockT is on a distinguished road
Re: Overlapping versus Blade headsails which is quicker ?

Quote:
Originally Posted by Stumble View Post
As mentioned above it really depends on the boat.

But typically a #2 (say 115-135) is the worst possible sail for any conditions. If you coukd ignore the spreaders and stay you could get a decent sheeting angle on them, but obviously you can't. This requires you to move the lead well outboard of the ideal sheeting angle. A 155 by comparison while having to go just as far outboard, also gets to come much further aft. So the angle between the centerline of the boat, and the line made from the tack to the clew is much smaller.

This is why most racing boats go from a 155 to the largest inside overlapping sail they can fly (typically a 115 or so). Not because reducing sail area isn't desirable, but because when you reduce area you also increase the sheet angle to such a point that it kills your pointing ability. And for most boats it is faster to be slightly over powered than to have to give up the pointing ability. Though there are boats this isn't true on, particularly very narrow for the leingth boats like an Olson 30, or Hobie 33.
That's not necessarily correct. In the area I race in, most boats have a #2 and they will shift down to that before they go with a #3. Perhaps it is because we are in a light to moderate wind area. There are many times when the #1 is too much power, but the #3 is not enough.

Tight sheeting angles on the headsail is not always what you are looking for, and the slot effect of overlapping sails should not be discounted.
Reply With Quote Share with Facebook
  #15  
Old 05-25-2012
Jeff_H's Avatar
Moderator
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,582
Thanks: 5
Thanked 95 Times in 71 Posts
Rep Power: 10
Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about
Re: Overlapping versus Blade headsails which is quicker ?

I agree that there are some rigs where a #2 is necessary. Its one of my big gripes with the CCA and IOR era rig proportions where the 155's are too big once the wind gets over a certain point, yet the jib is the prime motivator so that you can't afford to go down to a #3.

The original poster is talking about a modern fractionally rigged boat, where you don't need the extra sail in a #2 since you can power up and down to fill the gap, and frankly, due to the rig geometry a #2's lousey sheeting angle becomes the limiting factor for the whole boat when going upwind.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay and part-time purveyor of marine supplies
Reply With Quote Share with Facebook
  #16  
Old 05-25-2012
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,845
Thanks: 9
Thanked 75 Times in 68 Posts
Rep Power: 15
RichH will become famous soon enough
Re: Overlapping versus Blade headsails which is quicker ?

Simply look at JeffH's avatar ....

Youll notice immediately that the leech of the jib is (for the most part) operating in close proximity and 'just before' to the 'point of maximum draft' (POMB) in the main. What this positioning of jib's leech to POMB of the main is doing is yielding maximum 'bootstrapping' of two sails or which affects the best 'dumping velocity' from the jib to the main ... for maximum interaction flow between the two sails. Once the jib leech overlaps beyond or aft of the POMB of the main, aero-efficiency of the combo will start to rapidly decline .... although one can 'muscle' more speed (but not necessarily more 'lift' in direct proportion to the increase in SA) by increasing SA with a larger overlap.

I perceive this configuration is why the 'modern' frac rigs are generally carrying a lower LP jib and rarely a large LP jib ... for the combo of best boat speed AND pointing ability irrespective of 'sail area' considerations alone, ... also ignoring the geometry problems associated with sheeting angles on large headsails.

Whether this config. was determined aerodynamically or simply iterated by trial and error, it 'seems' to be in accordance with that which theoretically generates maximum aerodynamic conditions and output.
john f likes this.
Reply With Quote Share with Facebook
  #17  
Old 05-25-2012
Banned
 
Join Date: Apr 2011
Location: Southern California
Posts: 649
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
WDS123 is on a distinguished road
Re: Overlapping versus Blade headsails which is quicker ?

OP mentioned he sails at his Polars with the Blade.


Question would then be can he sail better than his Polars with a 155 ?


I doubt it.
Reply With Quote Share with Facebook
  #18  
Old 05-29-2012
Senior Member
 
Join Date: Jul 2006
Posts: 1,370
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 9
puddinlegs is on a distinguished road
Re: Overlapping versus Blade headsails which is quicker ?

Quote:
Originally Posted by Jeff_H View Post

The problem with the Hanses is that they are surprisingly high drag for a modern design, and do not have all that much standing sail area. They are also limited by their next to useless self-tacking set up which means that the normal jib is very small (90% or so), and does not set as well as might be ideal. It sounds like you have a custom set up which may let you use a 105-109% headsail.

Jeff, having just seen a Hanse 47, we watched the owner's crew takes down the self-tacker (yes, it's a really odd set-up... from the track, to the base of the mast, up the mast, in the mast, back down the mast, back to the cockpit ) and hoist a standard jib lead to standard genoa tracks/adjustable lead cars on the deck while preparing to race. I'm sure the boat sailed much better with the standard jib than with the self tacker. IMHO, self-tackers without a boom are pretty much useless, but I'm not expecting anyone to share my small thought on the matter.
Reply With Quote Share with Facebook
  #19  
Old 05-29-2012
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,845
Thanks: 9
Thanked 75 Times in 68 Posts
Rep Power: 15
RichH will become famous soon enough
Re: Overlapping versus Blade headsails which is quicker ?

Quote:
Originally Posted by puddinlegs View Post
IMHO, self-tackers without a boom are pretty much useless, but I'm not expecting anyone to share my small thought on the matter.
Totally agree you. Without a (vanged) 'boom' or clubfoot there is no effective way to control 'twist' when the clew is outboard. This is usually always seen especially on cutter rigs with only staysl and reefed main flying ... without a means to prevent the clew from rising, the upper panels of the stay'sl will be unattached to airstream flow/stalling, the foot overtrimmed and only a small zone of the middle part of the sail 'actually' working ..... same thing with almost ANY jib when the clew is well outboard. Even with fore/aft fairlead, etc. adjustment, etc. to control clew height ... with a sans 'boom' arrangement the jib will 'naturally' become deeper drafted .... more powerful but 'slower' when the clew is well 'outboard'. FLAT is faster in most conditions (in relatively flat water, etc.)

In the olden days before the 'rules changes' ... a reaching strut or jockey pole was used to help control the 'clew rise'. The Hoyt Boom in this respect is perhaps the best way to do this ... but unfortunately is impossible to apply to an 'overlapping' jib/genoa.
;-)
Reply With Quote Share with Facebook
  #20  
Old 05-29-2012
Jeff_H's Avatar
Moderator
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,582
Thanks: 5
Thanked 95 Times in 71 Posts
Rep Power: 10
Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about
Re: Overlapping versus Blade headsails which is quicker ?

Rich,

This is probably the other picture that you really wanted to make your point. Unfortunately we (Synergy and I) are not quite back up on a beat yet.

Jeff


[IMG]Photobucket[/IMG]
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay and part-time purveyor of marine supplies

Last edited by Jeff_H; 05-29-2012 at 06:39 PM.
Reply With Quote Share with Facebook
Reply

Tags
barber hauler , blade jib , genoa


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
2 blade or 3 blade propeller ddilman Gear & Maintenance 18 10-11-2012 09:00 PM
props - fixed 3 blade vs folding / feathering 2 blade BarryL Gear & Maintenance 2 01-25-2010 08:47 PM
2 Blade vs 3 Blade prop PBzeer Gear & Maintenance 23 01-02-2007 09:43 PM
Overlapping genny for a Columbia Sabre? noscreenname Racing 3 07-06-2006 02:31 PM
2 blade or 3 blade propeller ddilman General Discussion (sailing related) 3 02-12-2006 12:45 PM


All times are GMT -4. The time now is 01:22 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.