New Posts New Posts RSS Feed: V Twin
  FAQ FAQ  Forum Search   Register Register  Login Login

V Twin
 Post Reply Post Reply Page  <1 1718192021 142>
Author
  Share Topic Share Topic  Topic Search Topic Search  Topic Options Topic Options
Ruscoe View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 12 Jan 10
Online Status: Offline
Posts: 1514 		Post Options Post Options   Quote Ruscoe Quote  Post ReplyReply Direct Link To This Post Topic: V Twin
    Posted: 25 May 12 at 2:50pm
Originally posted by RS400atC

Originally posted by Ruscoe

I happen to agree about weight, Whilst there are some classes I believe would benefit from substantial weight loss (contender) I think a bit of weight helps with a boats "idle" characteristics.  I like a boat to be slightly less full on in between races, I like to be able to have a bit of control whilst launching and dumping my trolley.  Whilst a light boat accelerates quickly I guess it does not hold its momentum in the lulls as well.  Not to mention, a higher minimum weight (as a general rule) should help with longevity.

 

As an example, I am not sure a 49er would be any quicker if it was massively lighter.  I should imagine it would be one hell of a handful and would possibly spoil some of the class characteristics.


How much direct evidence does it take? The 49er's drag has been measured at various all-up weights, proving that  more weight= more drag at all speeds.

The performance of the 49er Fx recently shows that weight is not the only issue, quality of design, aerodynamic drag, and waterline length are all important factors too.

Regarding the ease of handling and stability, hull weight will usually improve static stability, but once the boat is moving, the hydrodynamics of the hull and foils are far more significant. Even a fairly traditional boat like the RS400 is far tippier when it's not moving. Of course if we were designing the 400 today, a lighter carbon rig would help static stability as well as speed through waves.
There is no doubt of any of that, also no doubt that the 9er is a fine boat and PDQ!  But treducing the hull weight SIGNIFICANTLY would change the characteristics of the boat, i should imagine in the 9ers case, not for the better.  I have no evidence hence why is said i Should imagine!!
 
 

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: 25 May 12 at 2:15pm
"why are you all so obsessed about the weight of the contender?  It's a bit like constantly asking 'does my bum look big in this?'

the answer is usually yes, but who gives a damn?"  Clap Still looks the most elegant wiring single hander to be had and feels like it's been brought up to have nice manners.

All design is compromise, super, super light is not always better it the broadest sense. It's just about what you want to optimise your design for, ultimate speed, ease of handling (on the beach or beating & tacking through heavy chop), cost, durability & ease of ownership.

I like reasonably light easily driven boats that accelerate away from a gust rather than getting knocked over and trying to round up. But then I also appreciate a little mass to help me through a particularly crucial tack in an unforgiving harbour mouth with rusty piling one side and boulders the other.  
Back to Top
robinft View Drop Down
Far too distracted from work
Far too distracted from work
Avatar

Joined: 18 Jun 04
Location: Thorpe Bay YC
Online Status: Offline
Posts: 252 		Post Options Post Options   Quote robinft Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:50pm
I raced Contenders in the eighties and even built 2 from scratch. I tried the 600 early in its life and didn't like it. Have sailed the 700 and MPS too and much preferred the MPS.
Laser number 9
Back to Top
winging it View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 22 Mar 07
Online Status: Offline
Posts: 3958 		Post Options Post Options   Quote winging it Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:50pm
why are you all so obsessed about the weight of the contender?  It's a bit like constantly asking 'does my bum look big in this?'

the answer is usually yes, but who gives a damn?
the same, but different...

Back to Top
Neptune View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 08 Jun 09
Location: Berkshire United Kingdom
Online Status: Offline
Posts: 1314 		Post Options Post Options   Quote Neptune Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:44pm
Originally posted by robinft

An RS600 is a Contender on weight loss and steroids. I much prefer the Contender, it's a proper boat.

possibly but then you sail a half cocked squib (sandhopper) also  Wink


Edited by Neptune - 25 May 12 at 1:44pm
Musto Skiff and Solo sailor
Back to Top
winging it View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 22 Mar 07
Online Status: Offline
Posts: 3958 		Post Options Post Options   Quote winging it Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:42pm
any minute now I'll be floating my mystery kevlar hull - very light - complete with contender mast (alloy) boom (carbon) and sail (dacron)  The hulls is probably 25 kg lighter than a contender hull BUT it is also 2ft shorter.  The shortness worries me more than the weight.

should be interesting though.
the same, but different...

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: 25 May 12 at 1:40pm
Less weight = less submerged boat = faster, but...

You can not just remove weight from an existing design and expect it to be better. The boat will float higher and therefore be on a narrower waterline. The centre of gravity will rise too (as you are losing the weight from low down). Both of these effects will reduce the initial stability of the boat, resulting in more and faster crew movement, and more playing of the sheets to keep the boat flat flat. Initial stability has a similar effect to a gust responsive rig - it dampens forces and automates what otherwise takes a lot of skill and fitness to achieve manually.
So less weight is generally faster in steady stae conditions, but not necessarily so in more dynmaic, transient conditions. A light boat should be designed to be light in the first place, rather than simply removing weight from a heavy hull.
Back to Top
Daniel Holman View Drop Down
Really should get out more
Really should get out more


Joined: 17 Nov 08
Online Status: Offline
Posts: 997 		Post Options Post Options   Quote Daniel Holman Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:30pm
Waterline length is king in dinghies until doing upwards of about 15kts boatspeed. Most dinghies never reach this.
I have not trawled the stats but the standard 9er is over 9ft wide - that is a colossal amount of RM, and any less than that on the other boats would mean giving away a lot of horsepower.
The 49er isn't a cleverer or more modern design than most of what was at the trials, it is just a long boat with stacks of RM, facilitated by having solid racks to get side to side. With tube racks you'd need a tramp of some sorts to bridge that gap.

Whoever said that a 49er wouldn't go faster with less weight is mislead. Displacement is a massive factor on boats operating in the semi planing and planing regimes. Resistance is pretty much proportional to total displacement. A large part of that is made up by the crew, so it is diminishging returns - bit like a race car engine - but still a very big deal.
Weight loss may make it a little bit more of a pain when pootling between races,  but I suspect not a lot - that has more to do with the nature of the boat and the rig.
Back to Top
RS400atC View Drop Down
Really should get out more
Really should get out more


Joined: 04 Dec 08
Online Status: Offline
Posts: 3011 		Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:29pm
Completely agree that very few one design classes would do well by reducing the minimum weight. That is a separate question from designing a new class, remember this is the Dinghy Development forum, not the One Design fan club.

Edited by RS400atC - 25 May 12 at 1:30pm
Back to Top
mongrel View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 27 Aug 08
Online Status: Offline
Posts: 304 		Post Options Post Options   Quote mongrel Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 12 at 1:18pm
Originally posted by Rupert

I'm sure the Contender could take 10kgs off without any trouble, as most newer ones carry that much in lead, now, but what exactly would they gain?
Max correctors is 6kg, but I agree you could take 10kg off, but I don't think there would be any benefit.  You would make the boats harder to build, more expensive to build, weaker, ruin longevity, and obsolete hundreds of boats world wide.  It may go marginally faster in a straight line, but would be harder to tack in breeze and less stable.
I think the only realistic way of introducing weight reductions in established classes is to first implement "an all up weight" rule.  For owners with heavier hulls they can make weight savings from foils, rig, rigging, fittings etc. which would enable them to still achieve minimum weight.


Edited by mongrel - 25 May 12 at 1:19pm
Back to Top
 Post Reply Post Reply Page  <1 1718192021 142>

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