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Lugger rudder

Printed From: Yachts and Yachting Online
Category: General
Forum Name: Repair & maintenance
Forum Discription: Questions & tips on the subject
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=13644
Printed Date: 21 Oct 21 at 8:18am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com


Topic: Lugger rudder
Posted By: Riv
Subject: Lugger rudder
Date Posted: 01 Aug 20 at 5:50pm
Yesterday I dropped our club's Drascombe Lugger rudder on my toe.
It's made from welded galvanised steel. Blade is 6mm thick.
I would like to make it lighter so I don't drop it again.
Does anyone know of a composite sheet material that in 6mm thick form will be strong enough and sink?


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Mistral Div II prototype board, Original Windsurfer, Hornet built'74.



Replies:
Posted By: JimC
Date Posted: 01 Aug 20 at 7:05pm
carbon/Foam sandwich ballasted with lead [grin].
More seriously perhaps aluminium might be lighter and hopefully strong enough


Posted By: Sam.Spoons
Date Posted: 01 Aug 20 at 8:00pm
I'd probably be considering taking more water with the rum ration..... Wink

More sensibly why did you drop it, was it simply 'cos it was too heavy? As Jim C says ally is roughly ⅓ the weight of steel and should be plenty strong enough for a rudder blade.


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Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"


Posted By: Rupert
Date Posted: 01 Aug 20 at 8:57pm
They are a hell of a weight. Not hit my toe, but laying them flat can go out of control if you aren't careful.

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Firefly 2324, Lightning 130, Puffin 229, Minisail 3446 Mirror 70686


Posted By: Sam.Spoons
Date Posted: 01 Aug 20 at 9:27pm
I'd look at an aluminium blade then, much lighter and reasonably cheap and easy for a local engineering company to make.

If you need it to sink under it's own weight then I'd think it needs a density of at least 2.0 g/cm3, aluminium has a density of 2.7 g/cm3, steel is around 8.0 g/cm3.


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Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"


Posted By: A2Z
Date Posted: 01 Aug 20 at 10:33pm
Anything with a density over 1g/cm3 will sink in freshwater...


Posted By: Do Different
Date Posted: 02 Aug 20 at 6:04am
Aluminium comes in many grades with varying properties of strength and corrosion resistance. Metalsupermarkets are an excellent source of information on all metals or any engineering firm capable of doing the machining should be able to suggest the correct spec.



Posted By: Riv
Date Posted: 02 Aug 20 at 9:26pm
The offending article.

This is as it would be hanging under the boat. You can see the top bearing bottom left of the picture and the narrow slot the stock will slide down,


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Mistral Div II prototype board, Original Windsurfer, Hornet built'74.


Posted By: Brass
Date Posted: 03 Aug 20 at 5:02am
Originally posted by Riv

The offending article.This is as it would be hanging under the boat. You can see the top bearing bottom left of the picture and the narrow slot the stock will slide down,

What a fearsome piece of ironmongery.


Posted By: Brass
Date Posted: 03 Aug 20 at 5:05am
Originally posted by JimC

carbon/Foam sandwich ballasted with lead [grin].
More seriously perhaps aluminium might be lighter and hopefully strong enough


Do you think the top bearing engineering needs that weight to keep the rudder and its post properly seated and immersed?

What would be the effect on fore and aft trim if you replaced it with alloy? Would you have to remove the half hundredweight CQR from the forward compartment?


Posted By: Pierre
Date Posted: 03 Aug 20 at 6:42am
Originally posted by Brass

Originally posted by Riv

The offending article.This is as it would be hanging under the boat. You can see the top bearing bottom left of the picture and the narrow slot the stock will slide down,
 
What a fearsome piece of ironmongery.

What an absolutely hideous thing. Surprised you didn't lose a toe.
There must be a better way than that.!!!




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