Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors

Go Back   Boat Design Forums > Design > Boat Design
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 10-12-2006, 12:40 PM
Scott Carter's Avatar
Scott Carter Scott Carter is offline
Senior Member
 
Join Date: Oct 2006
Rep: 143 Posts: 130
Location: Annapolis
Schooner sail plan - boomless foresail

I'm in the 11th hour of needing to get my rear in gear and get the sail plan to the loft for my boat. I have NO experience with a boomless sail other than headsails, but am nonetheless considereing it as an option for the foresail on my schooner. I know it's been done lots, and has been around for a long time. Can anybody give me an idea of what tradeoffs I might be making or other special considerations if I go this route which I haven't maybe considered.
My purpose for perhaps going this way is to help me get the lead down a bit without moving the masts, without decreasing headsails and without lengthening the main boom. Also, an outboard motor has already been ruled out by my expert design consultant Lucky Dog. 'preciate y'alls help on this one.
scott
Attached Thumbnails
Schooner sail plan - boomless foresail-sail-plan-boomless.jpg  
Reply With Quote
  #2  
Old 10-12-2006, 02:16 PM
M&M Ovenden M&M Ovenden is offline
Senior Member
 
Join Date: Jan 2006
Rep: 527 Posts: 183
Location: Ottawa
Gaff rigs are a great play ground and a well design gaff schooner rig can be a lot of fun to handle. Saying that, I'm not sure that that sail plan would be very satisfying, I'm not convinced that foresail is a great idea.
A non boomed sail will lead to a few problems. The first one is that you are rigging your boat with a wild weapon. The loose clew of a 1400sqft sail seems potentially dangerous.
A gaff rig sail usually does very good use of a heavy boom mostly on following winds. With too light of a boom the clew tends to go up and take an ugly shape, will happen even worst with no boom at all. Also, how well can you peek a boom less sail, won't you end up with with an ugly crease from the peak to the tack? I would be afraid that you would be giving up some power going higher in the wind. Don't underestimate the gain on peaking properly a gaff sail.
For handling it seems also like a hassle. A boomed sail tacks so nicely, I had no problem handling our schooner on my own. Only the non- boomed sails (jibs and staysail) were sometimes a bit more trouble in weather. If I was to have an other schooner I would consider a boomed staysail on a horse, it makes a huge difference for short hand crew.
An other though: those are big sails and gaff rigs are usually made of fairly heavy material, you'll want some lazyjacks, even more so for your aft sail as the boom sticks out. I don't know how lazyjacks are rigged on a boomless sail. Maybe it just get stowed like on loggers aginst the mast?

Are you thinking of this sail arrangement to bring back your center of effort (seemed to me it was more of a challenge to bring it forward) or to increase your sail area (most likely). To increase your sail area, it would be for lighter winds, have you considered a fisherman sail?
If you really want the overlapping foresail, you can still have a boom that ends before the end of the foot. I think it's called a lug-sheet forsail.

Murielle
Reply With Quote
  #3  
Old 10-12-2006, 05:31 PM
D'ARTOIS D'ARTOIS is offline
Senior Member
 
Join Date: Nov 2004
Rep: 321 Posts: 1,069
Location: The Netherlands
Who want really a gaff rigged boat - wether schooner or sloop?
Gaffs were used for stepped masts - for obvious reasons.

On a real classic, it is a matter of taste, not of necessity.
Reply With Quote
  #4  
Old 10-12-2006, 06:27 PM
safewalrus's Avatar
safewalrus safewalrus is offline
Ancient Marriner
 
Join Date: Feb 2005
Rep: 659 Posts: 4,756
Location: Cornwall, England
No problems with a boomless sail, you may need to rethink the lead of the sheets - the run of the sheet should bisect the sail i.e. run a line along your sheet up into the sail itself it should just about cut the sail into two equal parts! So you'll need to place the end of the sheet well aft to facilitate this! You'll need a brail on the sail to gather in the belly when not using the sail, atretch it from the foot of the gaff down to the clew and back up to the same point on the gaff then down to the deck - your best bet would be go look at some pictures of the standing lug and rig accordingly! You'll need to play a little to get it right but once your used to it there should be no problems (forget the bloody maths from the experts - go play)!
Reply With Quote
  #5  
Old 10-12-2006, 08:35 PM
PAR's Avatar
PAR PAR is offline
Yacht Designer/Builder
 
Join Date: Nov 2003
Rep: 3465 Posts: 11,668
Location: Eustis, FL
I've sailed with and without the lapping foresail on schooners and the lapper does offer a lot of power, but needs to be handled. Sheet leads can be a problem as you start running out of boat, or are married to the main boom. Your fore gaff appears too long to drop to the deck without some halyard gymnastics. Your gaff should be able to scandalize the sail, which requires it go below horizontal.

What is your current lead? Keeping in mind that a deadwood hung rudder, should be included in the lateral area calculations. Give yourself some latitude in step and partner adjustments, plus have the boom strive and distance between the sticks for additional rake, without banging heads or masts with the booms.

Aim for 9%, knowing it will increase as heel and wind strength increase. Figure the area of the fore triangle (staysail and jib only) and calculate the other two centers. You can alter the rig substantially by moving area around or with rake, before getting into different spars and their placement.
Reply With Quote
  #6  
Old 10-13-2006, 05:41 AM
FAST FRED FAST FRED is offline
Senior Member
 
Join Date: Oct 2002
Rep: 836 Posts: 3,606
Location: Conn in summers , Ortona FL in winter , with big dock & room for O'nite stop .
Your foresail , or any forsail can be more easily handled by stealing a concept from Dutch work boats.

They understood well the power of an overlaping sail , but with small crew needed to ease work while tacking.

The solution was a strong rope loop sewn onto the foot of the sail with a line (where a boom traveler would be) passed thru and tied off.
The line would work as a traveler , so the luff and most of the sail would begin working as soon as the tack was complete , sometimes they would fully sheet the sail, sometimes not bother , depending on the time to the next tack.

FAST FRED
Reply With Quote
  #7  
Old 10-13-2006, 10:22 AM
M&M Ovenden M&M Ovenden is offline
Senior Member
 
Join Date: Jan 2006
Rep: 527 Posts: 183
Location: Ottawa
Scott,

Rereading this thread I realized I read your post a little to fast as you do say your lapping sail is to reduce the lead.
Something else was bothering me on this sail plan and I just figured out what it was. Your staysail is much smaller than your jib. Usually they're closer to the same area size on schooners. Is there a reason you did it this way? By evening out the area of those to sails your CE would move slightly back, every little bit counts.
It looks a little funny to me a schooner with the biggest sail as the foresail. This is not sunk in concrete but more standard proportions for sail area on a schooner are about 50% for the main, 20% for the fore, 10% for the staysail, 10% for the jib and the last 10 for topsails.

For my current boat I really wanted to build a Brittany lugger I find them so cool (beauty is in the eye of the beholder). Our sail maker, who is a experienced with classic sails warned us about the inconvenient of boomless rigs. But we really liked the idea and had to find out on our own so my husband and I went to Brittany to find more about the rigs and try them. Turns out the lack of boom added to the work load and as we had be warned the sails could be more dangerous then the boom. The boats are really powerfull, I still love them but they need to be handled and it wasn't a realalistic choice for us.
This to say, maybe a boom less sail is fine and there are ways to deal with it, but there are drawbacks. You might want to find out by yourself before making a decision, sails are a big piece of the boat, they can make it a charm or a nightmare. It's only by trying you can really know if it fits your expectations. In my case I was very keen on boomless sail until I experienced it.
The main idea of a schooner is to split the rig to make sails more handable and, bermudian rig adepts can say what they want, it can be a nice to handle rig. On my schooner the fore sail was the don't worry about sail, I had 28% of my sail area that would tack on its own. Even if not perfectly adjusted , but because that sail is fairly centered, it wouldn't unbalance to much the boat and allow me time to care for jibs and main and get the boat quickly sailing on its own before adjusting the fore. Awesome with reduced hands to have one less sail to think quickly of. Even if a boom less sail is fine I doubt it would behave with as little care.
I also used my foresail under engine, to stabilize the rocking. It wouldn't power the boat to much and by being centered wouldn't affect the steering.
Your gaffs look to me like they could be peaked a little more, you might loose a bit more lead.

Cheers,
Murielle
Reply With Quote
  #8  
Old 10-14-2006, 12:10 PM
Pericles's Avatar
Pericles Pericles is offline
Senior Member
 
Join Date: Sep 2006
Rep: 1206 Posts: 1,677
Location: The heights of High Wycombe, not too far from River Thames
Scott Carter,

The archives section at Brian Eiland's site has a number of alternative rigs you could consider http://www.runningtideyachts.com/articles/

Here is one for a monohull.

http://www.runningtideyachts.com/monohull/

Pericles
Reply With Quote
  #9  
Old 10-19-2006, 12:21 AM
Gilbert Gilbert is offline
Senior Member
 
Join Date: Aug 2004
Rep: 28 Posts: 516
Location: Cathlamet, WA
I would suggest you pay attention to the comments by folks with gaff and schooner experience.
As drawn the gaff on your foresail is so long it will whack the main mast or stays and has all kinds of potential for grief. I would recommend shortening it so it can not touch the main mast. PAR already commented on the length of the gaff, as I recall.
Your staysail is too small. I have an article about the schooner rig written by Jim Emmett years ago in the Rudder magazine. He says a staysail that is too small is a "useless, hateful thing". L. Francis Herreshoff said that the peak of a jib or staysail is best if it has an angle of at least 29 degrees.
One good suggestion, I believe, is having a boomed staysail where the pivot for the boom is on a slide arrangement so it can be slacked forward or even rigged with a line and sheave so it can be pulled forward when lowering the sail so the sail will come down the whole way without having to go forward to deal with it. The boom should be as long as possible and still allow the sail to come down.
By all means, get your sailplan sorted out to your satisfaction before you place the order. Does your sailmaker have opinions on your proposed sailplan?
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Schooner sail plan- centers of effort Scott Carter Sailboats 15 11-05-2006 03:33 PM
Schooner Sail Handeling Jim Young Sailboats 8 09-22-2005 02:54 PM
Plan to fit sail kit - Any reccomendations? DrewBird Wooden Boat Building and Restoration 4 06-05-2004 07:12 PM
Sail & Rigging plan for 44' ketch Willallison Sailboats 4 01-15-2003 03:00 PM
Classic boats: how to design the sail plan? Gades Sailboats 6 08-01-2002 08:30 AM


All times are GMT -4. The time now is 09:22 AM.


Powered by: vBulletin Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2013 Boat Design Net