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Un-Fared Rudders.
http://www.hobie.com/forums/viewtopic.php?f=9&t=1489		 Page 1 of 2
Author:  Ballywho [ Tue Jan 25, 2005 2:27 pm ]
Post subject:  Un-Fared Rudders.
The Hobie I got last season had some major scratches on the rudder and every time I got up to speed (with triple trap "up to speed" is UP TO SPEED) I would get a hum that sounded like an outboardf engine. Any advice???
Author:  mmiller [ Tue Jan 25, 2005 2:49 pm ]
Post subject:  Rudder hummmmmm
Rudder hummmmmm is a fact of life, but there is a cure.

You have to trim the trailing edges.

From our support section is this sketch:

Image
Author:  widerisbetter [ Thu Jan 27, 2005 8:16 am ]
Post subject:  The reason that rudders hum
One day, long ago, under the inflence of a few oat-sodas, we figured out why Hobie rudders hum....

They forgot the words :roll: :lol:

Shine on you crazy hobie! 8)
Author:  aloa [ Tue Feb 01, 2005 9:22 am ]
Post subject: 
Ciao Ballywho,
I have the same your problem on my 1991 HC16.
It is a so boring problem I used my HC very few times, and I was thinking to sell it.
I would kike to know if you solve the problem following the very helpful instruction of mmiler.

PS: MMiller, thank you for spending your time to send us your fantastic answers.

Ciao!
Aloa
Author:  tchristian [ Tue Feb 01, 2005 9:37 am ]
Post subject: 
Not so long ago I was out day sailing 8) Screaming across Lake Texhoma. The Hobie Hummm was singing and all of a sudden a BIG hybrid Striper Hit the boat :shock: Anyone else had somthing similar happen while singing across the lake?

Todd
Author:  sunjammers [ Tue Feb 01, 2005 10:05 am ]
Post subject: 
If you blades are not plastic then you can use sandpaper and a sanding block to fix the problem. We take the block with us and hit the beach, sand a little then head back out and repeat as necessary. We do this all the time on new boats to get the singing out!


Thanks,
Brad Stephens
www.sunjammers.com
Authorized Hobie/Vanguard/Hunter Dealer
Hobie Division 15 Chairman
[email protected]
850-235-2281
Panama City Beach, FL
Author:  widerisbetter [ Tue Feb 01, 2005 10:56 am ]
Post subject:  Todd, can I borrow you to do some fishing?
It seems that we couldn't get away from schools of Bluefish when we were humming along off Assateague. Any time we got up to that speed you would hear the rudders bouncing off the fish. Weird!

Say Matt, does the rudder trailing edge trim refer to the black EPO's (or ELO's or BTO's, whatever :roll: ) too? I thought they were not to be messed with?
Author:  tchristian [ Tue Feb 01, 2005 11:28 am ]
Post subject: 
Matt How many types of rudders are there? Advantages?

Todd
Author:  Ballywho [ Tue Feb 01, 2005 2:05 pm ]
Post subject: 
By the way, I haven't but my dad caught a 5 pound bluefish when he submarined a 14 and it came up on the trampoline. Man thats alot of posts for 1 day keep them coming. Also I think fish are attracted to a certian pith. In my old 13 whaler whenever I ran at 4500 rpms sturgeons would jump close to the boat, twice they landed in it.
Author:  MBounds [ Tue Feb 01, 2005 4:24 pm ]
Post subject: 
Quote:
Matt How many types of rudders are there? Advantages?


In general, you want the rudders to be as light and stiff as possible. The profile is fixed by the class rules, as is the thickness.

The original 14 / 16 came with rudders of white PVC plastic. They have a nasty habit of getting brittle over time and snapping off right below the rudder casting. They're also not very UV resistant. They turn yellow in the sun.

There were a lot of aftermarket rudders being made out of fiberglass (heavy) and wood (pretty, but not very durable).

In the late 70's, Lexan rudders were introduced. Still heavy, totally unbreakable, but man did they flex! It was almost impossible to get a smooth surface finish on them. They were pretty much impervious to sanding.

Then in 1984 came the EPO Rudder (said with reverence). Foam core epoxy fiberglass. So light (about 4 lbs) that they changed the class rules to make them legal. Super stiff, super foil shape, hard superlative finish. Their only flaw was that they hummed miserably until you (very carefully) worked out the bulb on the trailing edge.

Unfortunately, they were only made for about 5 years. In 1989, Coleman sold Hobie Cat and away went the proprietary process that made the rudders. Until recently, nothing ever came close.

Since 1989, you could get the racer rudders (foam core fiberglass) - heavier than the EPO's, but nearly as stiff although the gel coat finish was a little soft compared to the EPO - or you could get the "plastic" rudders which I believe were made of polyester.

In the past year, though, Hobie Europe has brought out carbon fiber epoxy rudders that are very light (about 4.5 lbs) and very stiff. I just got a set for my 16, and I must say, they are very pretty.

But just last night, I got this photo in my e-mail:
Image

Hobie Cat is re-introducing the EPO rudder! Same foil shape - but digitally faired. The top one is carbon / epoxy; the middle one is carbon / Kevlar / epoxy and the bottom one is polyester.

*****drooooool*****
Author:  Ballywho [ Tue Feb 01, 2005 5:14 pm ]
Post subject: 
How much are they?
Author:  MBounds [ Tue Feb 01, 2005 5:36 pm ]
Post subject: 
I don't think Hobie Cat has settled on the pricing yet. Matt Miller said that they would be competitive with the European rudders. That would make them about $250. Each. (The polyester blades are certainly to be less expensive.)

Not for the faint of heart or the thin of wallet. Still, when you consider how much the racer rudders are, they're not that much more expensive. These rudders are not meant for the casual sailor.

The ones in the photo are prototypes that HC USA received this week (they are being made in Australia).
Author:  tchristian [ Wed Feb 02, 2005 12:29 am ]
Post subject: 
Euro? Australian? American?
"One Design"
What willl be standard with the new Hobies :?:

Honestly I give cudos for all of the work that has gone on with the Intenational Hobie. Wish the rest of the world would catch on.

Todd
Author:  mmiller [ Wed Feb 02, 2005 2:19 pm ]
Post subject:  Rudders
PVC, LEXAN, PCG, NYLON were all used. Glass-fiber-filled Nylon is the current material used for injected plastic rudders.

Matt Bounds was right. In the USA, we estimate the Carbon and Carbon Kevlars will be $250.00 each. The Polyesther version should be about $220.00 each (current cost of the racer). Pricing has not been locked in yet, but likely this will be it.

Rudders have always been open design for the 16, so any rudder that fits the profile and weight is legal.

These are not being built in Australia, but Steve Fields (Hobie Cat Australasia) played the major role in the development of the new blades. He discovered flaws in the foil shape, refined the trailing edge and reworked the layups. They have been testing the blades all season down there.
Author:  HC16Brazil [ Thu Feb 03, 2005 12:33 pm ]
Post subject: 
Here in Brazil every serious racer uses ruders made out of wood. They are very stiff, perfect finish and perfect trailling edge and very durable and very, very light. They are real state of the art pieces. They have just 2 problems, 1) they were made by an "wood artist" that is now too old to make them (over 90 years old) and 2)you have to take a lot of care of them (scratches and so on). Normaly here if you have a pair of these, you take it with you when you get a new boat, cause factory rudders here are not good quality - they flex a lot and break a lot !!!
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