New Posts New Posts RSS Feed: Star Sailors League
  FAQ FAQ  Forum Search   Register Register  Login Login

Star Sailors League
 Post Reply Post Reply Page  123 10>
Author
  Share Topic Share Topic  Topic Search Topic Search  Topic Options Topic Options
Guests View Drop Down
Guest Group
Guest Group
Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Topic: Star Sailors League
    Posted: 21 Dec 17 at 2:12pm
The wind turns the turbine, which turns a propeller under water. The boat moves upwind directly in to the wind. 

The blades on the turbine are effectively sails, but instead of pushing the boat in a direction of travel resisted by foils like conventional boat, they rotate and power a prop, which then pushes the boat in whichever direction you choose, including directly in to the wind. 

The last AC cup probably had the highest apparent wind angles ever seen. But because the boats were so fast the TW angle wasn't so impressive. 


Edited by mozzy - 21 Dec 17 at 2:15pm
Back to Top
Do Different View Drop Down
Really should get out more
Really should get out more


Joined: 26 Jan 12
Location: North
Online Status: Offline
Posts: 1312 		Post Options Post Options   Quote Do Different Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec 17 at 10:18am
"Those prop / turbine boats go directly in to the wind. The foils (prop) and sails (turbine blades) are constantly tacking while the hull travels directly upwind. "

Man you're frying my brain on that one  Confused. Trying to use O level physics, opposite and equal, friction losses............................. ?


edit add. BTW. with their very high speeds and apparent wind moving forward what angles do foiling boats get to true wind?


Edited by Do Different - 21 Dec 17 at 10:20am
Back to Top
Guests View Drop Down
Guest Group
Guest Group
Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec 17 at 9:02am
Those prop / turbine boats go directly in to the wind. The foils (prop) and sails (turbine blades) are constantly tacking while the hull travels directly upwind. 

But in terms of a conventional boat where the hull tacks then Id be surprised if it wasn't an IACC. You need a boat that is very efficient in every regard except carrying a load of lead to stop it building too much apparent. IACC fits that bill. 
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec 17 at 8:34am
Apart from Mozzy's answer, which is spot on, I'd think that boats like the Metre classes would rank very high on pointing ability. The old AC monohull also.
Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
Back to Top
Guests View Drop Down
Guest Group
Guest Group
Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec 17 at 8:30am
Originally posted by rb_stretch

 I would be curious which vessels point the highest upwind,

After many years racing I can conclude the vessel that points the highest is always the one starting immediately to leeward of me! 
Back to Top
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec 17 at 7:55am
Thing is, because of the affects of apparent wind, to point really high a boat must be both very low drag with a very efficient rig, but also rather slow for its size. A speed limited keelboat is always going to be favourite.
Back to Top
rb_stretch View Drop Down
Really should get out more
Really should get out more


Joined: 23 Aug 10
Online Status: Offline
Posts: 742 		Post Options Post Options   Quote rb_stretch Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 17 at 11:17pm
Originally posted by KazRob

I'm not sure on exact numbers for tacking angles but my usual trick of tacking when I can just see the mark when looking as far round behind my rear shoulder when hiking always ended up in being waaay over the layline in the Star. I learned to judge it looking over my forward shoulder and teh crew's head as he hiked but it did vary depending in breeze so never measured it. Prob 75-80deg if I had to guess tho


OK, very good for dinghies, but in the mix for racing keelboats. I'm sure the chines make a difference.

I would be curious which vessels point the highest upwind, I suspect the supermaxi's like Wild Oats XI must be right up there. Unfortunately I'll never get to experience it first hand.
Back to Top
KazRob View Drop Down
Far too distracted from work
Far too distracted from work
Avatar

Joined: 22 Oct 16
Location: Scotland
Online Status: Offline
Posts: 245 		Post Options Post Options   Quote KazRob Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 17 at 9:36pm
Rupert - I'm not sure as I think it might just be a SSL rule but I understand there is a proposal to include it in the Star championship rules above a certain windspeed. The crew has always been allowed on the foredeck as far as I know but around 15 years ago it was found to be a lot faster downwind as long as you could keep the boat upright (they have been know to capsize from a death roll) and the crew on the boat (it can be a bit slippy up there). Standing up tho allows the crew to spot the wind better as well
OK 2249
D-1 138
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 17 at 9:30pm
I was thinking of the wobbly downwind rule.
Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
Back to Top
KazRob View Drop Down
Far too distracted from work
Far too distracted from work
Avatar

Joined: 22 Oct 16
Location: Scotland
Online Status: Offline
Posts: 245 		Post Options Post Options   Quote KazRob Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 17 at 9:27pm
I'm not sure on exact numbers for tacking angles but my usual trick of tacking when I can just see the mark when looking as far round behind my rear shoulder when hiking always ended up in being waaay over the layline in the Star. I learned to judge it looking over my forward shoulder and teh crew's head as he hiked but it did vary depending in breeze so never measured it. Prob 75-80deg if I had to guess tho
OK 2249
D-1 138
Back to Top
 Post Reply Post Reply Page  123 10>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy