Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 26-06-2016, 06:53   #16
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: 50’ Jib-Schooner Sail Plan, aero analysis

Yes the naming of sails is a wonderful thing, full of all sorts of illogical historical quirks and romance. Traditionaly staysails were named from the mast that the top of the stay attached to so you got some salty sounding terms like the foretopmast staysail, and the main topgallant staysail.

For some reason the jibs were never called staysails, and I think that stems from the fact that the earliest jibs were not on stays but were set flying, before they even thought of making wooden hanks to attach the sail onto the hemp stay.

In yachting most of the cutter yachts had a stemhead staysail and a jib set flying off a bowsprit. Where as a sloop only had the one hanked on headsail on a shorter more sturdy bowsprit (or none), sometimes with an extra jibboom and a flying jib. I guess as yachts developed into something different the terms stayed.
__________________

__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 26-06-2016, 07:32   #17
Registered User
 
Steady Hand's Avatar

Join Date: Jul 2014
Location: Crewing All of 2017 Available Globally
Boat: OPB = Crewing in 2017
Posts: 4,851
Re: 50’ Jib-Schooner Sail Plan, aero analysis

Quote:
Originally Posted by Snowpetrel View Post
Yes the naming of sails is a wonderful thing, full of all sorts of illogical historical quirks and romance. Traditionaly staysails were named from the mast that the top of the stay attached to so you got some salty sounding terms like the foretopmast staysail, and the main topgallant staysail.

For some reason the jibs were never called staysails, and I think that stems from the fact that the earliest jibs were not on stays but were set flying, before they even thought of making wooden hanks to attach the sail onto the hemp stay.

In yachting most of the cutter yachts had a stemhead staysail and a jib set flying off a bowsprit. Where as a sloop only had the one hanked on headsail on a shorter more sturdy bowsprit (or none), sometimes with an extra jibboom and a flying jib. I guess as yachts developed into something different the terms stayed.


Enjoyed these recent posts of yours. Close to my understanding of the terms and development of the traditional cutter (with long bowsprits) and sloops.

Got a chuckle about the one inch taller foremast if you want a ketch instead of a schooner.

Flying jibs are cool.
__________________

__________________
Ahoy All Sailors! Need experienced crew for a passage or delivery in Atlantic, Pacific, Caribbean, Med, PNW, ICW, coastal or across an ocean anytime in 2017? I am available on 24hr notice. See my CF Profile "About Me" page for details. Happy to lend a hand!
Steady Hand is offline   Reply With Quote
Old 26-06-2016, 10:43   #18
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Upside down mainsail

BTW I think the term 'fisherman sail' is incorrect with respect to the rig under discussion in this subject thread. Most references describe a fisherman sail as a four-sided sail, ie
Notes on Sailing Small Schooners

More than likely the sail depicted in this jib-schooner plan might be termed a 'trysail' ?
Quote:
Originally Posted by Yobarnacle
Trysail Barkentine. Fore-n-aft rig more than two masts is a barkentine. The upsidedown mainsails ARE "Trysails".
reverse staysails, as it pertains to ketches, particularly the reverse or upsidedown - Boat Design Forums
Click image for larger version

Name:	trysails.jpg
Views:	65
Size:	332.6 KB
ID:	126942

...or perhaps even a 'mule' which is also a 3 sided sail rather than a 4-sided fisherman.
__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 26-06-2016, 20:08   #19
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: Upside down mainsail

Quote:
Originally Posted by beiland View Post
BTW I think the term 'fisherman sail' is incorrect with respect to the rig under discussion in this subject thread. Most references describe a fisherman sail as a four-sided sail, ie

More than likely the sail depicted in this jib-schooner plan might be termed a 'trysail' ?

...or perhaps even a 'mule' which is also a 3 sided sail rather than a 4-sided fisherman.
How easily we get off topic and how enjoyable it is...

Firstly I jave to say this is not the correct terminology "Trysail Barkentine. Fore-n-aft rig more than two masts is a barkentine":what: I know this is not your quote...

A Barkentine has the foremast rigged as a square, not a fore and aft mast. The rigging is totally different, its not about the staysails, as in you can't convert a three masted topsail schooner to a Barkentine just by removing the foresail and replacing it with a few staysails. The masting is completely different. Even though superficially it may look similar.

On that weird fisherman sail. Id probably still call it a fisherman myself. It rolls of the tongue nicely and isnt easily confused with any other sail. Its function, and postioning is similar to a "proper" four sided fisherman for me to be comfortable enough with it. The term mule is usually associated with something run up the backstay on a ketch. So I wouldnt call it that myself, and its not really a nice pleasant name for a sail. With its (possibly apt) connotations with the stubborn animal.

Trysail is what they often call the same sail on a wishbone ketch. And probably is the most correct term, but personally it us to easily confused with the modern use as a storm trysail.

So overall if it was me Id call it a fisherman and be quite happy to argue with any traditionalists who want to argue that that term only applies to four cornered sails. Most people would understand its function as a big light weather sail filling the space between the tips of the masts on a schooner.

If a big four sided overlapping fisherman spinnaker/light airs sail was used Id call it a Gollywobbler because it is the best name ever for a sail.
__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 27-06-2016, 07:04   #20
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Re: 50’ Jib-Schooner Sail Plan, aero analysis

Probably spent enough time on 'naming' those sails

Perhaps we can return to the aerodynamics of the situation as I started to discuss in posting #9
50’ Jib-Schooner Sail Plan, aero analysis
__________________
beiland is offline   Reply With Quote
Old 27-06-2016, 15:36   #21
Registered User
 
Hydra's Avatar

Join Date: May 2009
Location: Lorient, Brittany, France
Boat: Gib'Sea 302, 30' - Hydra
Posts: 1,229
Re: 50’ Jib-Schooner Sail Plan, aero analysis

The report says that the force coefficients for the sloop rig were derived from the ORC VPP aerodynamic model, i.e. *not* computed with CFD. Then, it's like comparing oranges to apples. A *serious* aero analysis would consist of 2 parts:
  • comparison of CFD computations for the sloop rig with VPP results, for calibration
  • CFD computations with the jib schooner rig
The shape of the jibs in the 90° AWA computation seems wrong to me: I can't understand how the sails remain so flat.

The CFD aero analysis says nothing about the vertical wind gradient considered in the study: in the real world, the friction of air on the sea surface causes a boundary layer to develop, reducing the true wind speed at low altitude (the first meters above the surface). This reduces the aero force generated by the lower part of the sails. If this were taken into account, it is possible that the 2-jib rig would give less aero force.

The analysis says nothing about the increase in drag resulting from the standing rigging (shrouds and spreaders) necessary for the second mast.

And it says nothing about the performance in reefed/furled condition or in a seaway (when the sea isn't flat any more and boat motions continuously change the apparent wind speed and direction).

Note: part of my work is subcontracting CFD computations and analysing the results...

Alain
__________________
Hydra is offline   Reply With Quote
Old 27-06-2016, 16:05   #22
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Re: 50’ Jib-Schooner Sail Plan, aero analysis

Thanks Alain, I was looking for something like that analysis of the Doyle study.
__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 28-06-2016, 13:58   #23
Registered User
 
Hydra's Avatar

Join Date: May 2009
Location: Lorient, Brittany, France
Boat: Gib'Sea 302, 30' - Hydra
Posts: 1,229
Re: 50’ Jib-Schooner Sail Plan, aero analysis

It's funny how posters were more interested in naming the sails than in comparing the performance of the rigs.

CFD computations taking into account the boat motions in a seaway would be at least 10 times more costly because this would imply coupling between boat motions and airflow on the sails.

Alain
__________________

__________________
Hydra is offline   Reply With Quote
Reply

Tags
sail, jib

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Dean Aero 44 catamaran Skipper63 Classifieds Archive 14 18-10-2013 14:03
Yes...another Aero-Rig question messias General Sailing Forum 7 09-03-2013 00:38
Aero Marine Winches - Anyone ? Cranston General Sailing Forum 3 04-08-2011 10:21
Dean 440 Aero Gambler Multihull Sailboats 0 08-08-2007 05:28
Aero Cal and The Moorings Redbull addict General Sailing Forum 5 07-05-2006 08:25



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.