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rudder damage #150732
07/28/08 10:16 AM
07/28/08 10:16 AM
Joined: Apr 2004
Posts: 713
WA, ID, MT
davefarmer Offline OP
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davefarmer  Offline OP
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I ran the Javelin hard this weekend, and while disassembling it for storage I noticed the damage pictured. The rudder skins are crushing a bit where they nest in the bottom of the casting when in the down position. I can repair the damage no problem, but would like to understand the cause in hopes of preventing further problems.
It seems that these rudders are hollow and fairly thin skinned. There is some slop at the rudder pivot point which I can shim up, that might be the cause. I try not to slam the rudders into the down position, but....Suggestions for shim material? I've been cutting discs out of the tops of cottage cheese containers. Any other HT owners experiencing anything similar? Joe? Bill?

Thanks, as always!

Dave

Attached Files
153192-rudders001.jpg (229 downloads)
-- Have You Seen This? --
Re: rudder damage [Re: davefarmer] #150733
07/28/08 10:17 AM
07/28/08 10:17 AM
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WA, ID, MT
davefarmer Offline OP
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another pic

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153193-rudders002.jpg (180 downloads)
Re: rudder damage [Re: davefarmer] #150734
07/28/08 10:39 AM
07/28/08 10:39 AM

A
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Quote
I've been cutting discs out of the tops of cottage cheese containers.

2% or 5%??

just kidding, i purchase soup that comes in plastic storage containers from my local grocery store. the lids are a little thicker than i find in pre-packaged items like you mentioned and work well for me.

Re: rudder damage [Re: davefarmer] #150735
07/28/08 12:15 PM
07/28/08 12:15 PM
Joined: Aug 2005
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Michigan
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I think those are just gelcoat fractures/scrapes from when you pull the rudders down. Personally, I wouldn't do much about them other than maybe build them up a little with thickened epoxy next time you make a batch for something else.

Re: rudder damage [Re: PTP] #150736
07/28/08 01:14 PM
07/28/08 01:14 PM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
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Some of it looks like usual wear, but those cracks and missings bits are scary. My immediate thought was structural and too much bending in that part. As this is mostly above the "working part" of the foil, I would have had a go at reinforcing it rather than risking a break. Hollow foils with gelcoat sounds like an oxymoron, but I know as good as nothing about Bimare products.

To "fix" it I would have sanded and put on some glass. When hard I would have added epoxy thickened with microfibers and collodial silica, put on a very thin layer of plastic film and put the foil in the "down" position in the rudderhead. Then clean up around the rudderhead section. Perfect fit and more durable than gelcoat.

Re: rudder damage [Re: Rolf_Nilsen] #150737
07/28/08 01:24 PM
07/28/08 01:24 PM
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A friend with an HT actually ground out part of that area on his rudders to let the rudders rake a little more forward for balancing purposes.
The rudders and boards on the HT are hollow which always bothered me because I didn't figure having water in them constantly was very good for them.

Re: rudder damage [Re: Rolf_Nilsen] #150738
07/28/08 04:37 PM
07/28/08 04:37 PM
Joined: Apr 2004
Posts: 713
WA, ID, MT
davefarmer Offline OP
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Yeah, that sounds good Rolf, there's plenty of extra room inside the castings and additional thickness and strength would be welcome. I'm sure this is a major stress point for the rudders, as they attempt to bend sideways under load.
I'm also not so pleased with the hollow rudders and water intrusion. My thought is to fill that little hole down low, as well as the 2 I created for the hold down/lift lines, then maybe drill a small hole on the top of the rudder to minimize the amount of water that gets in. Has anyone completely sealed the rudders? I don't leave mine on the boat when stored, they might sit in the sun a few hours between sessions at most.

Dave

Re: rudder damage [Re: davefarmer] #150739
07/28/08 08:11 PM
07/28/08 08:11 PM
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SE Pa. or Chesapeak Bay
HMurphey Offline
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I've seen the same on my Hobie and Prindle rudder blades ... Remember the Hobie castings w/ that small plastic adjustment screw?

I agree w/ Rolf!!! I would use two layers of cloth tape 2" and 4" to spread the load out.

Little trick: when you know what rudder rack you like ... wrap "plastic wrap" around the blade ... put a glob of silicone inside the casting ... push the blade into place allowing the silicone to ooze out ... it will coat the inside of the casting ....

This makes a "bumper" inside the casting. It can be easily removed and redone.

Sail Safe, Sail Flat, Sail Fast
Harry Murphey
H18mag, #9458/ Fleet54,Div11
P18MX, #86? CRAC

Re: rudder damage [Re: HMurphey] #150740
07/29/08 02:27 AM
07/29/08 02:27 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
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Before bringing out the grinder or going sailing again, I would try to get in contact with Bill Vining.

I have some experience with hollow foils, built by Marstrøm. They had one hole on top, and even with a piece of tape over the hole there was water inside them. Was a regular maintenance job to get all the water out and dry them.

Re: rudder damage [Re: Rolf_Nilsen] #150741
07/29/08 08:58 PM
07/29/08 08:58 PM
Joined: Apr 2004
Posts: 713
WA, ID, MT
davefarmer Offline OP
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I've got the rudders repaired and back in the castings, shimmed properly. There's much less slop, which should reduce the side loads some. I have filled all the holes, one of them with silicone, in the hope that if pressue builds the silicone would give before the rudder explodes.
I like your ideas on bedding the rudder in the down position in either epoxy or silicone. Thanks guys, I hope to be back on the water tomorrow!

Dave

Re: rudder damage [Re: davefarmer] #150742
07/29/08 09:49 PM
07/29/08 09:49 PM
Joined: Aug 2005
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Michigan
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I would be more afraid of the pressure building up than of the water intrusion.
as for bedding the rudder in the casting with silicone.. I tried that and it wears away really easily. the epoxy should work but be careful how much you are changing the balance. I guess if you only build up the sides then it shouldn't be an issue.

Re: rudder damage [Re: davefarmer] #150743
07/30/08 06:59 AM
07/30/08 06:59 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
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Dave,
Sorry I didnt chime in on this sooner, I didnt notice the thread.

The top of the HT rudders where the wear is in your pictures is pretty solid. There's some foam up in the head of the blade around the edges. So you can grind away that spot with the gel coat crack and still have material to work with when you repair it.

Next time you need to fix them try white Marinetex. Its basically thickened epoxy colored white, and it matches the white gelcoat color that Bimare uses pretty well.

I've filled the holes on my hollow Bimare blades and they dont seem to mind it, I dont believe you ever have enough pressure change to hurt them unless you are trailering your boat over the Rocky Mountains or flying them around in your airplane.

The castings are soft aluminum and they are probably wearing out too, it might be time to make a mold for new carbon ones.

Re: rudder damage [Re: PTP] #150744
07/30/08 07:13 AM
07/30/08 07:13 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
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I have filled the holes on both the rudders and daggers and made new holes on the top of the daggerboards and covered them with tape.

I never understood why Bimare put the holes at the bottom of the foil. If they want a pressure release hole it should be above the waterline so it wont leak. And the hole is so small that getting water out is practically impossible. WF used to suck the water out, which is something I've tried and really dont recommend, salt water plus vinylester is quite possible the most horrible taste on earth.

packing tape works to cover the hole pretty well, or if its above the water line colored electrical tape works good. too.

If anyone out there has a broken Bimare HT foil - dagger or rudder or both, or ever breaks one, please either send it to me or take pictures, I'd love to see where the are hollow vs solid.

Re: rudder damage [Re: bvining] #150745
07/30/08 11:33 PM
07/30/08 11:33 PM
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Gainesville, FL 32607 USA
dacarls Offline
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The HT rudders look a lot like the white fiberglass Bimare A-cat rudders: These have composition foam top 1/3, corrugated (wavy- vertical) fiberglass middle 1/3, hollow bottom 1/3.
Unfortunately I have seen a number of the insides of these fiberglass rudders, but not the carbon ones that don't break. Bimare Boards do tho.

BTW- I left my 1 year old carbon rudders with water inside in the back of my car- in the hot sun with tape on the little holes. Do NOT DO THIS. The heads swelled. I had to compress them in a vise, drill and put my Hobie 16 Quik-Fit rudder cam pins thru the rudder heads so they would fit between the castings. Bad Juju.


Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison

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