Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 23-06-2010, 03:22   #121
Registered User
 
Eleven's Avatar

Join Date: Sep 2007
Location: Southampton UK
Boat: Jaguar 22 mono called Arfur.
Posts: 1,220
Images: 3
See, there could be effective solutions!
Gyro's may be confused by swell, a water-pressure thro hull might make more sense, certainly for easing, if not releasing the sheets. And the slipping clutch on the fishing rod is adjustable, so it's down to the owner to set it right, or the Hirer to Lock in the position that provides the insurance premium he wants to pay. From all the above input's it's hard to see why Insurers haven't been putting up fees to an extent where the Hirer's need to protect their boats better.
New Boat builders would surely see better customer response to reversing winches (electric optional), over torque limiters, and computer aided sail trimming. Even the bigger FP's would absorb these costs quite readily, and the cruising experience would be improved considerably. Just look at the money that goes into Chart Plotter and linking them into the steering. It only takes a marine PC to link all that to wind direction to steer the boat on best course within safety margins. Just needs the right bunch of people to work together, like folk who want to make money ( or have too much time on their hands and miss using their old skills) while cruising.
__________________

__________________
Ex Prout 31 Sailor, Now it's a 22ft Jaguar called 'Arfur' here in sunny Southampton, UK.
A few places left in Quayside Marina and Kemps Marina.
Eleven is offline   Reply With Quote
Old 23-06-2010, 06:06   #122
Senior Cruiser
 
Captain Bill's Avatar

Cruisers Forum Supporter

Join Date: Apr 2008
Location: On the boat
Boat: Endeavourcat Sailcat 44
Posts: 2,313
With regards to placement of the rudders ahead of the saildrives this was probably done for reasons more to do with internal space use than performance. The FP boats are known for having isolated engine rooms that can be holed or more precisely have the saildrive water seals fail for any given reason and not flood the boat. It also gets the hot engine out of the living space by putting it in the end of the boat. This is probably not the best for placement of the rudders. For a given size rudder its effectiveness is partially determined by the length of the lever arm it has with which to act. The longer the lever arm the less force the rudder has to generate to turn the boat or to counteract weatherhelm. If the rudder is further forward it either needs to be bigger or it needs to have a higher angle of attack to generate the same force turning force as a rudder further aft. A larger rudder adds drag and a higher angle of attack adds drag. The issue is that a short coupled rudder under a high load condition and a high angle of attack is more subject to exceeding its critical angle of attack and stalling. Once stalled the rudder ceases to be able to control the boat and if it's counteracting a large amount of weatherhelm when it does the boat is going to turn rapidly to weather and out of control. This sounds like what happened in this case.
__________________

__________________
Captain Bill is offline   Reply With Quote
Old 23-06-2010, 06:44   #123
D&D
Marine Service Provider
 
D&D's Avatar

Cruisers Forum Supporter

Join Date: Nov 2008
Location: Blue Mountains, Australia
Boat: now working Syd Harbour charters
Posts: 1,459
Quote:
Originally Posted by Captain Bill View Post
If the rudder is further forward it either needs to be bigger or it needs to have a higher angle of attack to generate the same force turning force as a rudder further aft. A larger rudder adds drag and a higher angle of attack adds drag. The issue is that a short coupled rudder under a high load condition and a high angle of attack is more subject to exceeding its critical angle of attack and stalling. Once stalled the rudder ceases to be able to control the boat
Captain we begin by acknowledging our lack of expertise. We are following the technical aspects of this thread like hanging onto a wing in flight with fingernails...barely!

Starting then with no expertise and really very limited knowledge we pause in the comments above to ask...isn't it the case that a rudder further forward would reduce (and very likely eliminate) both ventilation and cavitation around the rudder, two primary causes of stalling for rudders further aft?
__________________
D&D is offline   Reply With Quote
Old 23-06-2010, 08:06   #124
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,424
Quote:
Originally Posted by Captain Bill View Post
With regards to placement of the rudders ahead of the saildrives this was probably done for reasons more to do with internal space use than performance. The FP boats are known for having isolated engine rooms that can be holed or more precisely have the saildrive water seals fail for any given reason and not flood the boat. It also gets the hot engine out of the living space by putting it in the end of the boat. This is probably not the best for placement of the rudders. For a given size rudder its effectiveness is partially determined by the length of the lever arm it has with which to act. The longer the lever arm the less force the rudder has to generate to turn the boat or to counteract weatherhelm. If the rudder is further forward it either needs to be bigger or it needs to have a higher angle of attack to generate the same force turning force as a rudder further aft. A larger rudder adds drag and a higher angle of attack adds drag. The issue is that a short coupled rudder under a high load condition and a high angle of attack is more subject to exceeding its critical angle of attack and stalling. Once stalled the rudder ceases to be able to control the boat and if it's counteracting a large amount of weatherhelm when it does the boat is going to turn rapidly to weather and out of control. This sounds like what happened in this case.
To continue this.......if the rudder is 'connected' and counteracting weather helm, it shouldn't become 'unconnected' by an increase in speed (at least at the speed of sailboats), wouldn't it take a change in angle of attack to cause it to disconnect (the helmsperson turned up to counteract the short burst of increased weather helm due to a gust)?
__________________
DotDun is offline   Reply With Quote
Old 23-06-2010, 09:50   #125
cruiser

Join Date: Aug 2005
Location: No longer post here
Boat: Catalac Catamaran
Posts: 2,462
I think you guys are on the wrong track. I believe what happened is a COG issue, not a rudder issue,
__________________
Tropic Cat is offline   Reply With Quote
Old 23-06-2010, 10:39   #126
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,313
EH, why do you feel using the adjective niggling is a typo?






definition of

niggling
  1. 1
    a niggling feeling is slight but it worries you continuously Synonyms or related words for this meaning of niggling: serious, severe, grave, worrying, disturbing... more

Quote:
Originally Posted by Event_Horizon View Post
Cute typo
__________________
Joli is offline   Reply With Quote
Old 23-06-2010, 11:32   #127
Registered User

Join Date: Apr 2007
Location: Hawaii
Boat: Atlantic 42 Catamaran
Posts: 293
Quote:
Originally Posted by Eleven View Post
See, there could be effective solutions!
Gyro's may be confused by swell, a water-pressure thro hull might make more sense, certainly for easing, if not releasing the sheets. And the slipping clutch on the fishing rod is adjustable, so it's down to the owner to set it right, or the Hirer to Lock in the position that provides the insurance premium he wants to pay. From all the above input's it's hard to see why Insurers haven't been putting up fees to an extent where the Hirer's need to protect their boats better.
The safety record of charter style catamarans (and cruising catamarans in general) is very good. Most cruising cat capsizes are a result of gross negligence on the part of the user. Virtually every construct of civilization can be made safer. However, with most things there is a point of diminishing returns where making something a very little bit safer costs quite a lot (in money or utilitarian terms). From a practical standpoint I think multihulls are safe enough when used as intended. I am so convince that I sail my catamaran offshore as a matter of course. We're getting pretty worked up about a case that certainly involved a good bit of operator error and perhaps some design defects and still didn't result in a capsize.

Tom.
__________________
tsmwebb is offline   Reply With Quote
Old 23-06-2010, 12:56   #128
Registered User

Join Date: Aug 2009
Location: Land-locked at the moment :(
Posts: 189
Quote:
Originally Posted by Joli View Post
EH, why do you feel using the adjective niggling is a typo?






definition of

niggling
  1. 1
    a niggling feeling is slight but it worries you continuously Synonyms or related words for this meaning of niggling: serious, severe, grave, worrying, disturbing... more

haha that is wonderful. Though, there is no surprise I haven't heard that word before, growing up in the DC area and all...I imagine the the thought process to go something like this:

duck -> duckling
tree -> sapling
goose -> gosling
@%&#$& -> niggling

Then the next few moments of my life would be my last.
__________________
Event_Horizon is offline   Reply With Quote
Old 23-06-2010, 13:38   #129
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,424
Quote:
Originally Posted by tsmwebb View Post
The safety record of charter style catamarans (and cruising catamarans in general) is very good. Most cruising cat capsizes are a result of gross negligence on the part of the user. Virtually every construct of civilization can be made safer. However, with most things there is a point of diminishing returns where making something a very little bit safer costs quite a lot (in money or utilitarian terms). From a practical standpoint I think multihulls are safe enough when used as intended. I am so convince that I sail my catamaran offshore as a matter of course. We're getting pretty worked up about a case that certainly involved a good bit of operator error and perhaps some design defects and still didn't result in a capsize.

Tom.
I agree! And, I too use my cat offshore as a cruiser, not a race boat.

What it costs me in extra effort for paying closer attention sailing a cat compared to a monohull is more than paid back in the remaining 95% of the cruise that's spent at anchor.
__________________
DotDun is offline   Reply With Quote
Old 23-06-2010, 13:38   #130
Registered User

Join Date: May 2010
Posts: 316
Dennis: Gyros are Greek lamb sandwiches. But you make a very good point about being upside down is all that matters.

Eleven: I like the embryo idea, but you're too late. There's already a guy with a thread in here on sending his goat 'round the world solo.

Me, I can't believe I made it all the way through this stuff. Amazing amount of information.
__________________
Drew13440 is offline   Reply With Quote
Old 23-06-2010, 14:17   #131
Registered User

Join Date: Feb 2006
Location: Anacortes, WA
Boat: Maine Cat 41
Posts: 325
It's all easy to say things like, "one shouldn't have to reef at 25 knots on a cruising cat" or that lifting a hull unexpectedly in under 30 kits "shouldn't happen or is 'unsafe'. What is realign being revealed here is one's 'expectations' instead of quantifiable fact. I am confident that the owner's manual would give a suggestion for when to reef (if it says anything at all). My boat didn't come with such a thing--it was anticipated that I, the owner, would use good judgement. The big knock on multihulls is that they are less forgiving in unexpected wind conditions. It's a risk that can be managed but not eliminated. In other words, captain beware! For me, I carefully monitor wind conditions constantly. The fact that the gust could be seen coming, says to me that the OP was watching but underestimated the affect on his craft. Fortunately, the outcome was benign. Another thing, wind instruments usually approximate the info. I've seen too many gauges and too much instrumentation giving erroneous numbers to ever be 100 per cent confident in what they tell me. Unfortunately, these days we have been lulled into a sense of complacency all too often.

So could this have been avoided? Only by exercising a more conservative approach to one's expectations.... And by not assuming that everything will be as one "thinks" it will be. Nonetheless, stuff happens. Yeloya thanks for sharing, it's a good reminder of our need to be vigilant and expect the unexpected"
__________________
cchesley is offline   Reply With Quote
Old 23-06-2010, 18:38   #132
Registered User
 
Wayward Wind's Avatar

Join Date: Jul 2006
Location: Pittwater
Boat: Mahe 36 Wayward Wind
Posts: 226
I remember asking our FP distributor here in Oz a while back about the new square top sails. He said one advantage is that it spills wind to enable the Lipari to depower. Anyone know more about this?
__________________
Wayward Wind is offline   Reply With Quote
Old 23-06-2010, 18:39   #133
Registered User

Join Date: Jun 2010
Posts: 1
as if you would flip over

Interesting indeed to read all this excitement. A lot of rocket scientists around here... Sure they can give the novice yard some advice on how to build boats.
Has it ever occurred to yeloyo to get in touch with the manufacturer and ask for some explanation? Apparently not the case. Strange for a customer with allegedly so many FPs in his charter fleet... One official version would help don't you think? Rather expose it all on a forum first and stir up the hornets' nest. Any good reason for it?
Much more fun I must admit...
__________________
pg4yacht is offline   Reply With Quote
Old 23-06-2010, 18:56   #134
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Quote:
Originally Posted by pg4yacht View Post
.
Has it ever occurred to yeloyo to get in touch with the manufacturer and ask for some explanation?
...
He said he was going to do that (don't know the post #) and I am waiting for thier reply.
I am pretty sure he will let us know.
__________________
Therapy is offline   Reply With Quote
Old 23-06-2010, 19:07   #135
D&D
Marine Service Provider
 
D&D's Avatar

Cruisers Forum Supporter

Join Date: Nov 2008
Location: Blue Mountains, Australia
Boat: now working Syd Harbour charters
Posts: 1,459
Quote:
Originally Posted by pg4yacht View Post
Has it ever occurred to yeloyo to get in touch with the manufacturer and ask for some explanation?
Thanks Therapy...and you're quite right, of course.

pg$yacht, check out Post #71 where Yeloya makes it clear he intends to speak to FP. As we suggested in Post #85, however, FP will probably say Yeloya shoulda reefed...ah, the clarity of hindsight!...and FP will almost certainly not admit any design fault.

So the Forum is indeed a useful place to air the experience both because FP's response seems predictable and, very importantly, because it is a topic of great interest, as we can see from the numerous and often very detailed responses! In fact, Yeloya's post is now being aired and extensively discussed on at least two other sailing forums as well.

So we repeat our thanks to Yeloya for opening the door to this discussion.
__________________

__________________
D&D is offline   Reply With Quote
Reply

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
Which Is More Forgiving - Cruising Monohull or Cruising Multihull maxingout General Sailing Forum 36 10-02-2010 06:41
Cruising Cat vs. Cruising Mono Performance ssullivan Multihull Sailboats 100 03-01-2010 14:05
on the verge... blove8 Meets & Greets 5 07-10-2007 15:18



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:57.


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.