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19-01-2014, 07:23
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#451
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Registered User
Join Date: Mar 2007
Location: Tavernier, Fl
Boat: Outremer 50
Posts: 750
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
I know there are no rudder stops in the pictures but it is inconceivable to me that there would be none. I would bet there are in fact rudder stops, just not installed in the traditional location.
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19-01-2014, 07:34
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#452
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Registered User
Join Date: Jul 2013
Location: cornwall uk
Posts: 574
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Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by 44'cruisingcat
I take it from this, you've never actually seen a rudder....
There is no gap between the top of the rudder and the entrance to the bushing.
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[ATTACH]74271
Bend or break ! You choose ? This was 70mm on a 43ft mono
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19-01-2014, 07:48
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#453
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Senior Cruiser
Join Date: Jan 2010
Location: PORTUGAL
Posts: 30,618
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Quote:
Originally Posted by Dave852
I know there are no rudder stops in the pictures but it is inconceivable to me that there would be none. I would bet there are in fact rudder stops, just not installed in the traditional location.
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The 'Stop' is the actual tiller bar.. with set screws and pins... only one was omitted...
The one with the pin failed under pressure due to 'poor?' bonding to the shaft... the one without the pin broke its screw, and as a result went right round, bent and jammed..
Assumption.. no techie expert..
__________________
You can't beat a people up (for 75yrs+) and have them say..
"I Love You.. ". Murray Roman.
Yet the 'useful idiots' of the West still dance to the beat of the drums.
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19-01-2014, 08:03
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#454
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Elvish meaning 'Far-Wanderer'
Join Date: Jan 2008
Location: Boat - Greece - Me - Michigan
Boat: 56' Fountaine Pajot Marquises
Posts: 3,489
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Re: Alfa 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by 44'cruisingcat
I take it from this, you've never actually seen a rudder....
There is no gap between the top of the rudder and the entrance to the bushing.
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I really appreciate your knowledge on catamarans after viewing the pictures of your build. No doubt your an expert on them. But just because someone disagrees with you doesn't mean they are idiots and have never seen a rudder sticking out from the bottom of a boat.
__________________
Our course is set for an uncharted sea
Dante
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19-01-2014, 08:11
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#455
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Moderator Emeritus
Join Date: May 2008
Location: Fort Lauderdale, FL
Boat: 48 Wauquiez Pilot Saloon
Posts: 5,975
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Quote:
Originally Posted by Cotemar
No Rudder Stops in the Alpha 42 rudder design was the cause of its demise.
Most all production Cats have rudder stops, so the rudder cannot go hard over and become a barn door. The rudders have too much surface area to be hard over and have a large hydrodynamic force against them.
Here are a few pictures of a FP Helia 44 with rudder stops allowing a 30 to 45 deg rudder dead stop.
Alpha 42 rudder post and arms in the bottom pictures with No Rudder Stops
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Therein lies the secret.... did or didn't stops exist??? Even if they did, I'll bet they weren't adjusted for the "best preventative condition"...
I've adjusted the stops on the Morgan... Was getting better hard over motion from the boat 5 degrees narrower...
On a J120 I was crewing on, the stop positions were incredibly inadequate... Hard over produced no boat correction on one point of sail... To the extreme of "holding the helm" against the stop!
I'll bet if that boat was forced backwards, it would have a similar rudderstock failure (or something else would give)
__________________
In the harsh marine environment, something is always in need of repair...
Mai Tai's fix everything...
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19-01-2014, 09:28
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#456
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Moderator
Join Date: Jul 2009
Location: Sxm , Spain
Boat: CSY 44 Tall rig Sold!
Posts: 4,367
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Re: Alfa 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by 44'cruisingcat
I take it from this, you've never actually seen a rudder....
There is no gap between the top of the rudder and the entrance to the bushing.
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Actually i see many in the last 28 years, back to the isue maybe i dont explain well or you dont get the idea, the rudder shaft fit inside of the rudder post by bushings or bearings the point where it exit the rudder stock in the bottom is the weak point, and yes between the top of the rudder and the bottom hull there is gap to allow the rudder to move free and rotate without rubbing the hull, and no idea why im quote you again because you should know in fact, your the guy who build a catamaran...
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19-01-2014, 09:38
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#457
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Registered User
Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,108
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Re: Alfa 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by neilpride
yes between the top of the rudder and the bottom hull there is gap to allow the rudder to move free and rotate without rubbing the hull,
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There is no gap on ours. There is a washer between the rudder post bearing and the rudder. Any gap that exists is measured in thousandths of an inch.
I do, however, believe that a bend can still happen in this area, because I think the stock here can elongate during bending forces, as well as the stock just inside the rudder skin top can be bent. Also, the rudder body foam can be forced down on the internal webbing and expose a bit of shaft.
Mark
__________________
www.svreach.com
You do not need a parachute to skydive. You only need a parachute to skydive twice.
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19-01-2014, 09:44
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#458
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Registered User
Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,108
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Does anyone know what that small thing is wired up near the rudder posts?
As for stops, I don't see any evidence that they did not exist. Yes, they are not noticeable in the pictures, but those pictures only show the rudder stocks and tiller bars. They do not show the quadrants or ends of the tiller bar, where stops would normally be placed.
At the very least, the autopilot drive would be providing 35* maximum travel and act as a stop. That is assuming this is mechanical steering.
Mark
__________________
www.svreach.com
You do not need a parachute to skydive. You only need a parachute to skydive twice.
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19-01-2014, 09:49
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#459
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Moderator
Join Date: Jul 2009
Location: Sxm , Spain
Boat: CSY 44 Tall rig Sold!
Posts: 4,367
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Re: Alfa 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by colemj
There is no gap on ours. There is a washer between the rudder post bearing and the rudder. Any gap that exists is measured in thousandths of an inch.
I do, however, believe that a bend can still happen in this area, because I think the stock here can elongate during bending forces, as well as the stock just inside the rudder skin top can be bent. Also, the rudder body foam can be forced down on the internal webbing and expose a bit of shaft.
Mark
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+1.....
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19-01-2014, 09:55
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#460
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Moderator Emeritus
Join Date: May 2008
Location: Fort Lauderdale, FL
Boat: 48 Wauquiez Pilot Saloon
Posts: 5,975
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Quote:
Originally Posted by colemj
Does anyone know what that small thing is wired up near the rudder posts?
As for stops, I don't see any evidence that they did not exist. Yes, they are not noticeable in the pictures, but those pictures only show the rudder stocks and tiller bars. They do not show the quadrants or ends of the tiller bar, where stops would normally be placed.
At the very least, the autopilot drive would be providing 35* maximum travel and act as a stop. That is assuming this is mechanical steering.
Mark
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Probably not the bent shaft sensor...
Kidding aside, it's on both sides... 12-14 Ga??? to with a connector to "itty bitty gauge"??? Courtesy lights for the transom steps?
__________________
In the harsh marine environment, something is always in need of repair...
Mai Tai's fix everything...
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19-01-2014, 09:56
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#461
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Registered User
Join Date: Oct 2010
Location: Gig Harbor, WA
Boat: 34' Crowther tri sold 16' Kayak now
Posts: 5,067
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Quote:
Originally Posted by colemj
Does anyone know what that small thing is wired up near the rudder posts?
Mark
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I think someone here said that is the rudder angle sensor but it looks different than the few I'm familiar with. How does it work???
__________________
Slowly going senile but enjoying the ride.
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19-01-2014, 10:12
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#462
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Registered User
Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,108
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
No, the rudder angle sensor was connected with the threaded rod shown in one of the pictures. Maybe those are LED lights on the stern step?
Mark
__________________
www.svreach.com
You do not need a parachute to skydive. You only need a parachute to skydive twice.
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19-01-2014, 10:35
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#463
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Registered User
Join Date: Oct 2010
Location: Gig Harbor, WA
Boat: 34' Crowther tri sold 16' Kayak now
Posts: 5,067
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re: Alpha 42 "Be Good Too" rescue 300 miles off Cape Henry Merged
Update from Charles Doane.
BE GOOD TOO: Answering Critics | Sailfeed
I think he's been reading this thread.
__________________
Slowly going senile but enjoying the ride.
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19-01-2014, 11:39
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#465
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Registered User
Join Date: Sep 2006
Posts: 9,398
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Re: Alfa 42 "Be Good Too" rescue 300 miles off Cape Henry
Quote:
Originally Posted by Palarran
I really appreciate your knowledge on catamarans after viewing the pictures of your build. No doubt your an expert on them. But just because someone disagrees with you doesn't mean they are idiots and have never seen a rudder sticking out from the bottom of a boat.
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I don't claim to be an expert. But I've never seen bare rudder shaft sticking out of the bearings. Every single spade rudder installation I've seen on a cat has had the rudder body up against a thrust washer, which is against the bottom of the bearing tube.
I'm very likely going to a hardstand today, so I'll pay more attention.
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