Author Topic: rudder blades  (Read 1972 times)

duncan

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rudder blades
« on: November 21, 2007, 04:15:28 PM »
Duncan,  & still missing the (liquid) bar on the 10 tonner 

Tim Gatti

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Re: rudder blades
« Reply #1 on: November 22, 2007, 12:41:47 PM »
Hi Duncan - I suppose the depth of the water is one determining factor, so you might want to base blade length on minimum depth available if you're working with a fixed rudder. Don't think there's any rule governing actual blade length.

Alternatively a lifting blade with uphaul/downhaul cords and cleats would enable you to raise the rudder when going through shallows, and drop it again in deeper water, so you'd have the best of both worlds.

Tim

mutt

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Re: rudder blades
« Reply #2 on: November 22, 2007, 04:15:38 PM »
Or perhaps you should consider a daggerboard rudder. They are quite easy to fix halfway up with a an elastic loop around the trailing edge of the rudder (above the stock). This system makes steering a lot easier when the board is half up as it doesn't sweep the water like a lifting rudder does.
Matt

Ken Goddard

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Re: rudder blades
« Reply #3 on: November 23, 2007, 10:10:27 PM »
Duncan,
as a previous owner of N.3024, "Smile" I should say I never had any trouble with the length of the rudder, even on the shallows of the Trent. However, on another boat where I shortened the rudder by about 4inches/10cm I started getting into control trouble down-wind in stronger winds. I advise leaving the rudder as it is, and taking up Tim's suggestion of have a control line so that you can pull the blade up a bit in the shallows. Another alternative which I noticed John Cheetham using, is to have a separate shorter blade which you can substitute before the race when the winds are feeble.
Regards
Ken Goddard

Roly Mo

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Re: rudder blades
« Reply #4 on: November 24, 2007, 09:21:05 AM »
I have a short blade which I use for Norfolk Week (once you've hit a cockle bed at full tilt with a full length rudder it somehow seems worthwhile having a second blade and stock!!).  It's about 6 inches shorter than my normal blade - it's a real work of art and I bought it secondhand from Nigel May.  Others sail with considerably shorter blades than that, but as Ken says it is a fine balance between being able to control the boat and finding yourself in trouble.  Why not use strong elastic for the downhaul - that way if you do hit something there's a bit of flexibility and give?  I would be inclined to go with the uphaul/downhaul suggestion and try that to start with.

RM

JohnKn

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Re: rudder blades
« Reply #5 on: November 24, 2007, 02:50:18 PM »
I sail on Hornsea Mere in East Yorkshire, which has a number of shallow areas which can catch out the unwary (the ANEYC National 12 meeting a few years back saw a number of breakages).

I have a hinged rudder with a shockcord downhaul which lets the blade lift (and drag) on impact, and pulls it down when clear. A cord uphaul lets you raise it when launching and landing - or to clear weed.

John (1662)
JohnKn
N1662

duncan

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Re: rudder blades
« Reply #6 on: November 26, 2007, 03:01:16 PM »
Many thanks all, I have just aquired an old 2nd hand blade & I will try shortening for light winds, will nibble away at it each week.  Quite agree that a short blade in windy weather is tricky, don't want a high speed capsise & inversion.  
We have a depth of about 6 ft for most of the loch with long weed by the end of the summer, which long rudders/cbs catch on.  Wish the environmentalists would stop the farmers using so much fertiliser which just washes off into the river & loch.   Duncan
Duncan,  & still missing the (liquid) bar on the 10 tonner 

Tim Gatti

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Re: rudder blades
« Reply #7 on: November 27, 2007, 12:35:23 AM »
If it's not already - then it might be worth painting your new rudder blade white - that way it's easier to see if there's weed on it.

Usually you only look when you're trying to work out why the rest of the fleet suddenly seems to have left you standing!  

Hope your shortened-blade does the trick.

Tim

Jerry G

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Re: rudder blades
« Reply #8 on: November 27, 2007, 09:43:46 PM »
Duncan
Having spent this afternoon at a course on agricultural nitrate pollution I can confirm that DEFRA (Department for the Elimination of Farming and Rural Activities) is currently amending the rules relating to Nitrate Vulnerable Zones in compliance with the EU nitrates directive.  Soon most of England will have increased regulation of nitrate fertiliser and manure use etc.  However, for some reason Scotland and Wales have very limited areas designated as NVZs, so hard luck!  Before blaming farmers for all nitrates consider the output from sewage effluent and industrial processing and be aware that airport runways are de-iced with urea (46% nitrogen) rather than salt, so where does that all end up!
Having got that off my chest.  Our shallow river estuary can get quite weedy by late summer and I have adapted a plastic stick with a V piece at the end (at right angles to the stick) which can be used to push lumps of weed off the rudder without the need to raise and lower the blade.  An easily raised blade with elastic to hold it down may be OK in low speed boats but tends to lead to a disconcerting loss of control when speed gets really exciting.  I use a non-stretch line to a clam cleat on the tiller (the sort that trips and releases if the rudder hits something really solid).  An alternative is the old style tubular jammer which usually allows some slip if you hit something hard.  I also clamp the rudder with a large wing nut when its down to avoid any play between tiller and blade.  Its a trade off really: easy raise and lower with wobbly rudder versus fixed rudder as weed collector and possible serious damage if grounded - or something in between.

 

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