Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-06-2016, 03:17   #16
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,826
Images: 2
Re: Curious idiot question #1

Quote:
Originally Posted by valhalla360 View Post
It's a little more complicated but in rough terms 50% ahead of the hinge point is the critical point. At that point, it will take no effort to turn the wheel as the turning force in front and the force behind will cancel out. This has a couple of bad results:
- You can't feel the forces on the rudder at all so it's not always clear what position it is in. This makes it hard to sail a straight line as there is no tactile feel.
- In the event of a failure, the rudder will wind up in a random position, so you may be stuck sailing in circles.
It's actually about 25% from the leading edge to shaft where the forces are equal, more or less depending of the foil shape, speed and angle of attack. This is due the lift of the rudder which is most close to the leading edge..

BR Teddy
__________________

__________________
TeddyDiver is offline   Reply With Quote
Old 14-06-2016, 05:42   #17
Registered User

Join Date: May 2010
Posts: 666
Re: Curious idiot question #1

big wheels and a few turns lock to lock make for less twitchy helming and so looking away for a second doesn't cause you to veer off course too greatly, but more than a few seconds and you'll probably have turned 90 degrees.
__________________

__________________
dlymn is offline   Reply With Quote
Old 14-06-2016, 06:00   #18
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: Curious idiot question #1

Must say I have come to like the big wheel on my boat. It gives fingertip control from many different positions in the cockpit. It has enough intertia to be spun lock to lock very quickly. It obstructs the cockpit a bit, but everthing is a compromise.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app
__________________
My Ramblings
Snowpetrel is offline   Reply With Quote
Old 14-06-2016, 07:01   #19
Registered User

Join Date: Apr 2016
Location: Lake Belton, TX, USA, Earth: 3rd rock from the Sun
Boat: Vagabond 14
Posts: 422
Re: Curious idiot question #1






I'll stand by the pivot line being closer to 27% than 45%.... and 50% being WAY OUT.
__________________
TurninTurtle is offline   Reply With Quote
Old 14-06-2016, 09:25   #20
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Curious idiot question #1

As has been a bit heated to death the reason for a big wheel is leverage. The larger the wheel, the more of it you have without needing to introduce more friction into the system. But there is a bit of an upper limit, at some point the wheel size just gets stupid.

A larger wheel also allows the driver more options of where to sit, generally allowing him to sit as far outboard as possible for the best view of the sails. Smaller wheel restrict this ability. But still super large wheels get stupid on very wide modern boats.

So people started to move to twin wheels. This allows the best size of wheel to be selected, while also allowing the driver to sit as far outboard as possible. They ar not just a silly cosmetic option, there is real purpose to having split wheel systems.


Finally on rudder design... A balanced spade ideally has the rudder post 17% aft of the trailing edge on a vertical rudder. The reasons you guys gave are correct, but the placement was a little off.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 14-06-2016, 09:56   #21
Registered User
 
Juho's Avatar

Join Date: Apr 2015
Location: Finland
Boat: Nauticat 32
Posts: 716
Re: Curious idiot question #1

Quote:
Originally Posted by landlockedsquid View Post
I didn't realize the force was that great.
Thanx for the responses.
In modern sailboats the force is usually not that great. I can steer my boat with one finger. If not for the good looks, the key reason nowadays must be to allow the helmsman to sit on either side (for better visibility around, and to the sails, and for better weight balance). Same reasons behind having two steering wheels.
__________________
Juho is offline   Reply With Quote
Old 14-06-2016, 09:56   #22
Registered User
 
Manos1955's Avatar

Join Date: Jul 2012
Location: Thessalonki Greece
Boat: Westerly Centaur 26
Posts: 153
Send a message via Skype™ to Manos1955
Re: Curious idiot question #1

You will find large steering wheels on racing sailing boats
Cruisers have hydraulic steering so there is no need for large steering wheel
Reason that racing boats avoid hydraulics and go for large steering wheel is usually the weight
A hydraulic steering for a 45 racing footer it is tooooo heavy and racing boats need to be light weight
My ex racing boat the once "UNIBANK II" a 45 one off had such a large steering wheel and it was a piece of cake to steer her even in the worst weather condition
She had also a tiny engine , only 27 HP, again to save weight
__________________
Manos1955 is offline   Reply With Quote
Old 14-06-2016, 09:58   #23
Registered User

Join Date: Mar 2015
Location: channel islands
Boat: lancer 36
Posts: 268
Re: Curious idiot question #1

Quote:
Originally Posted by landlockedsquid View Post
So I got this response in my thread "cat question" And while it is fairly insulting to me, I also thought it was a very funny post.
So, I thought I would start a thread series asking my curious idiot questions, since I have about a ton of em.
So heres the first one.
Why is the wheel on a sailboat so big?

Now, in case you're thinking this is some kind of joke, it isn't. I really don't know, and am wondering why.
i upsized to the largest wheel that would fit on my boat for one reason. i sit as far to one side or other as possible when steering. driving from the center of a sailboat has never made sense to me. that's while tiller's have hiking sticks. single handing most of the time i can see so much more as regards sail trim, wave action, heel angle, etc., from the rail than i can from the center of the boat. and weight on the high side in a blow is crucial while crew on the low side in light air will heel the boat increasing water line length and helps with sail shape.
__________________
jrbogie is offline   Reply With Quote
Old 14-06-2016, 10:06   #24
Registered User

Join Date: Sep 2013
Location: San Francisco Bay
Boat: Chung Hwa Boat Builders, Magellan 36
Posts: 262
Re: Curious idiot question #1

50% back for pivot location is much too far back. Even the often suggested 25% back makes for a twitchy steering at speed. I have built a half dozen rudders and found 10% to 15% back makes for a well behaved rudder. Which means it has some feel but doesn't require excessive force
__________________
foufou is offline   Reply With Quote
Old 14-06-2016, 10:29   #25
Registered User

Join Date: Feb 2011
Posts: 2,105
Re: Curious idiot question #1

Usually its easier to helm a boat from the windward side. Big wheel allows you to steer from whatever side is convenient for you. Also, its way easier to steer a wheel when you standing at its side then directly in back of it. Directly in back steering tends to mean over/under steering since folks treat it like a car steering wheel(its not)
Steering from the side forces you to steer according to the boat's natural drift off course. You steer ahead of the boat's movement, not afterwards. Its way easier to get into this rhythm when you are abreast of the wheel, not behind it.
__________________
reed1v is offline   Reply With Quote
Old 14-06-2016, 10:41   #26
Registered User
 
captmikem's Avatar

Join Date: Mar 2014
Location: Ft Lauderdale
Boat: KP 46
Posts: 317
Images: 2
Re: Curious idiot question #1

Airplanes have balanced rudders as well, here is a photo of my plane, notice the top of the rudder is balanced so that airflow over the top portion counteracts the force of the wind over the rest of the rudder when the rudder is turned.

(hopefully these photos will appear in the proper order)

Now, here is a photo of my boat’s rudder, no balance at all, but it handles easily with a 3’ wheel at 1.5 turns lock to lock. Contrary to what a few have said, the “feel” of the boat through the wheel is important, has the boat heels one feels a bit more pressure, if the boat is balanced the pressure is slight, but if you have no pressure the boat will ten to wander, this happens often with hydraulic steering.

I have built several yachts and did a lot of work on the proper size wheel to the rudder. Here is an 80’ Frers design I built at Palmer Johnson, and subsequently sailed her around the world. She had a 7 foot wheel on a balanced rudder, not quite 1 turn lock to lock. The diameter was this large so one could sit on either side and steer. She sailed like a dream (German Frers is a wizard), and when she would surf at 14 knots (took a BIG sea to surf her), you could steer her with two fingers.

And here is one more boat I built up in Maine at Hodgdon. BIG rudder. She has hydraulic steering with two large wheels, we tried to get feedback with hydraulic gear, but she never really had any feel in either wheel.


Hope this helps,

Michael
Attached Thumbnails
Click image for larger version

Name:	plane.JPG
Views:	84
Size:	102.6 KB
ID:	126153   Click image for larger version

Name:	tara.JPG
Views:	81
Size:	118.2 KB
ID:	126154  

Click image for larger version

Name:	turmoil.JPG
Views:	85
Size:	132.0 KB
ID:	126155   Click image for larger version

Name:	sch rudder.JPG
Views:	85
Size:	94.4 KB
ID:	126156  

Click image for larger version

Name:	sch wheel.JPG
Views:	87
Size:	77.7 KB
ID:	126157  
__________________
captmikem is offline   Reply With Quote
Old 14-06-2016, 10:42   #27
Registered User

Join Date: Jun 2015
Posts: 1,168
Re: Curious idiot question #1

Why have a wheel at all if leverage is not a consideration?

TrentePieds is fin keeled and has a spade rudder, regrettably. The rudder stock is set too far back at about 30% cord. 18% cord is good bei mir. My wheel wrecks the back porch for living space, and the house is high enuff to require standing up to see over it. Or leaning out quite far. I'm gonna have a go at a tiller with a hiking stick :-)!

TrentePieds
__________________
TrentePieds is offline   Reply With Quote
Old 14-06-2016, 10:59   #28
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Curious idiot question #1

Quote:
Originally Posted by Manos1955 View Post
You will find large steering wheels on racing sailing boats
Cruisers have hydraulic steering so there is no need for large steering wheel
Reason that racing boats avoid hydraulics and go for large steering wheel is usually the weight
A hydraulic steering for a 45 racing footer it is tooooo heavy and racing boats need to be light weight
My ex racing boat the once "UNIBANK II" a 45 one off had such a large steering wheel and it was a piece of cake to steer her even in the worst weather condition
She had also a tiny engine , only 27 HP, again to save weight
The reason race boats don't have hydrolic steering is not because of weight, but because of feel. A hydrolic system dampens the feeling of what's going on with the rudder, which is why you don't want a perfectly balanced spade. A slight imbalance allows the helmsman to feel how the rudder is responding but this is only achievable with direct drive.

I actually don't know many small sailboats (<100') built in the last 25 years that use hydrolic steering at all. With modern balanced rudders there really isn't a need to do so. Balanced spade rudders can be designed to a given helm load pretty easily, so why go thru the complexity of a hydrolic system where you don't need one.

The only exception maybe for full keel or unbalanced skeg rudders that can't use better design to reduce the loads.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 14-06-2016, 11:19   #29
Registered User
 
bobnlesley's Avatar

Join Date: Jul 2008
Location: Yorkshire/Back down in da islans Mon
Boat: Trident Challenger- 35 feet
Posts: 369
Re: Curious idiot question #1

Quote:
Originally Posted by valhalla360 View Post
On modern boats a lot of it is for looks (ie; wow mister, you sure do have a big...).
There's definitely some of that at times. When we bought our 35' boat it was fitted with a 36" diameter wheel; you had to walk across the cockpit seating to get around it! We immediately changed that for a 30" wheel and a year or so later, we fitted a 24" wheel - much better for circulation - though we kept the 30" one 'just in case we ever need a bigger wheel, heavy weather and such.' It's never gone back on since and I have never felt short of leverage, nor do I recall there being any significant/noticeable loss of leverage at either reduction in diameter; perhaps if I'd gone directly from 36" to 24" things may have been different? Gearing is just short of one turn either way from centred to full rudder and in most of our heavy-weather steering experiences, the windvane's done the steering; it connects to a hub of only 6-7" diameter, irrespective of what sized wheel it's clamped to.
__________________
bobnlesley is offline   Reply With Quote
Old 14-06-2016, 11:23   #30
cat herder, extreme blacksheep
 
zeehag's Avatar

Cruisers Forum Supporter

Join Date: Jul 2008
Location: furycame alley , tropics, mexico for now
Boat: 1976 FORMOSA yankee clipper 41
Posts: 17,767
Images: 56
Send a message via Yahoo to zeehag Send a message via Skype™ to zeehag
Re: Curious idiot question #1

my fin spade set up had large stainless wheel.
my barn door deep full keel has a small wood wheel. is easier to steer and tracks much better, due to design and intended use.
__________________

zeehag is online now   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
A Curious Battery Question redsky49 Electrical: Batteries, Generators & Solar 13 31-05-2012 10:37
Idiot or Hero? Hud3 General Sailing Forum 106 02-08-2008 00:34
Idiot Lights Charlie Electrical: Batteries, Generators & Solar 28 28-07-2008 08:52
Idiot or Hero? (mk2) 44'cruisingcat General Sailing Forum 14 15-12-2007 21:27
I am an Idiot and deserve to drown swami maximus Engines and Propulsion Systems 17 01-06-2007 22:54



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:15.


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.