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Question on Extensions

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Created by ryanjh > 9 months ago, 18 Oct 2017
ryanjh
15 posts
18 Oct 2017 5:20AM
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Hi,

I ordered a Goya Nexus 6.9 sail and know that the luff length on it is 469. The mast I have is a RDM 460 and I use a US cup base (now regretting not getting Euro Pin).

My question is where to find a skinny extension that will accommodate my luff length of 469. I believe the minimum setting on a Chinook aluminum skinny extension is 12cm. I didn't know how bad of an idea it would be to put a little less downhaul on and use that on the minimum setting.

Thanks,
Ryan

buzzy
TAS, 2433 posts
18 Oct 2017 8:40AM
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www.surfsailaustralia.com.au/shop

Minimum 6cm

FormulaNova
WA, 14129 posts
18 Oct 2017 6:11PM
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I was taught to make sure that there is no slack in the lines between the tack and the outhaul pulley.

Since then, I have realised it pretty much doesn't matter. As long as you are putting on the correct downhaul for the sail, the actual numbers and extra line don't matter. In fact, I get annoyed now when people look at my rigged sails and critique them without even looking at the sail shape and just go from the numbers printed on it. Some sails just don't rig correctly using the numbers, whether its slightly different masts, or just poor sail accuracy.

So, use your extension, allow extra line, and just ignore anyone that tells you 'it's wrong'.

sailquik
VIC, 6074 posts
18 Oct 2017 10:24PM
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buzzy said..
www.surfsailaustralia.com.au/shop

Minimum 6cm




The one in that link does not look like it would go that short. Are you sure that is the link you intended?

I think I have seen a Streamlined 2 pin ext that does go shorter though.......

BTW, FormulaNova is right. Even a slightly different mast can change the downhaul length markedly. I had a rigging session last WE with my 5.4m Koncept with two RDM masts that are from the same factory and differ by no more than 1% curve. But the best rigged luff length varied by 3cm!

gorgesailor
598 posts
19 Oct 2017 1:18AM
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You should also know that extension which go lower basically just have the pulleys set higher on the base. For instance the Chinook US cup version has the pulleys down below the bottom of the extension, whereas the Streamline has them very high on the tube - this is kind of an artificial way to make your extension go lower. Like has been said, just don't pull the sail all the way to the tack pulleys. Learn to rig by sight.

grich62
QLD, 663 posts
19 Oct 2017 8:56AM
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Select to expand quote
ryanjh said..
Hi,

I ordered a Goya Nexus 6.9 sail and know that the luff length on it is 469. The mast I have is a RDM 460 and I use a US cup base (now regretting not getting Euro Pin).

My question is where to find a skinny extension that will accommodate my luff length of 469. I believe the minimum setting on a Chinook aluminum skinny extension is 12cm. I didn't know how bad of an idea it would be to put a little less downhaul on and use that on the minimum setting.

Thanks,
Ryan



i don,t get what you are saying, most extension i own have a minimum extension of 50 mm ,dont count your base and joint in the equation, just set it to 100mm and only pull down to 90 as the others said the numbers are guides set for personal choice.i own sdm and rdm extensions ,i think they are radz brand they are all 50 mm miinimum

John340
QLD, 3063 posts
19 Oct 2017 9:51AM
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grich62 said..

ryanjh said..
Hi,

I ordered a Goya Nexus 6.9 sail and know that the luff length on it is 469. The mast I have is a RDM 460 and I use a US cup base (now regretting not getting Euro Pin).

My question is where to find a skinny extension that will accommodate my luff length of 469. I believe the minimum setting on a Chinook aluminum skinny extension is 12cm. I didn't know how bad of an idea it would be to put a little less downhaul on and use that on the minimum setting.

Thanks,
Ryan




i don,t get what you are saying, most extension i own have a minimum extension of 50 mm ,dont count your base and joint in the equation, just set it to 100mm and only pull down to 90 as the others said the numbers are guides set for personal choice.i own sdm and rdm extensions ,i think they are radz brand they are all 50 mm miinimum


Ryan's point is, that if the sail is made to spec and the mast is to spec and he wants the tack of the sail close to the mast base, then he needs an extension setting of around 6cm. The minimum setting on alloy US cup RDM extensions on most brands and models is 10 to 12cm. Streamlined have a carbon RDM extension with US cup with a minimum 6mm extension, but is expensive at 170 USD. See the following URL

http://www.streamlined.us/extensions/copy-1-of-rdm-hmx-us

Ryan's options are:
1. Invest in the streamlined carbon extension
2. Use his existing extension and rig with 4 to 6cm distance between downhaul pulleys
3. Rig on a 430 mast and use his existing extension (if it can accommodate 36cm extension)
4. Change to Euro cup mast bases and extensions
5. Cut 4 to 6cm off the bottom of his existing 460mast

Ant-man
NSW, 177 posts
19 Oct 2017 3:54PM
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I have made a slow change over a couple of years to all streamlined RDM hardware, pin style extensions, mast bases, boom heads, booms. It does cost a bit more but I went direct from the US and it was (over time) affordable. The old Chinese proverb comes to mind, buy expensive - cry once, buy cheap/unusable - cry many times. I just can't fault their products

buzzy
TAS, 2433 posts
19 Oct 2017 9:44PM
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sailquik said..

buzzy said..
www.surfsailaustralia.com.au/shop

Minimum 6cm





The one in that link does not look like it would go that short. Are you sure that is the link you intended?




Just going off the description given down further in the ad, Daffy. Streamline site has the new model listed as 7cm for both aluminium and carbon. Below is a pic of older model I had lying around, it's the same as the one shown in the ad.







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"Question on Extensions" started by ryanjh