Optimum Crew weight??
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=1377
Printed Date: 15 Aug 25 at 6:36am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: Optimum Crew weight??
Posted By: Oatsandbeans
Subject: Optimum Crew weight??
Date Posted: 16 Jan 06 at 1:07pm
|
I was wondering if anybody has ever tried to predict what the optimum crew weight would be for a dinghy based on the sail area and the Beam (or righting moment). I have been looking at some of the classes and the relationship is not as clearly defined as you would think. Anyone got any comments or am I just a bit sad and I should get out of the office more?? |
Replies:
Posted By: nick.r
Date Posted: 16 Jan 06 at 7:23pm
|
Its very dependant on boat wieght and wavelength because it determins how easy the boat is to drive though chop and waves. The wieght also follows the top guys wieght alot. optimum wieht always varys from year to year. anyone else with any imput? ------------- Laser 4.7 174571 national squad. 29er 1115 |
Posted By: Guests
Date Posted: 16 Jan 06 at 7:45pm
|
I agree with Nick, in that the optimum weight follows whoever happens to be leading in that particular class at the time. i guess there should really be a formula for adding in all the variables and ending up with a preferable optimum weight for each boat. But unless ur sailing olympic classes where the vast majority tends to be top of the game then really optimum crew weights count for very little in comparison to sailing ability. On that note though, i do seem to remember there being something about sail carrying power in relation to crew weights in the mighty bible bethwaite book...hmmmm, me thinks im gonna go have a read! |
Posted By: HannahJ
Date Posted: 16 Jan 06 at 7:54pm
yer me and my dad once worked out part of the formula based on where
most pressure is on the mast, how far out of the boat yuo are hiking
and that distance from the centre line, and how much pressure on the
sails, therefore what crew weight is needed in different wind speeds.
I'll see if i can dig it out, i'm not sure how far we got...
------------- MIRROR 64799 "Dolphin" The pessimist complains about the wind; the optimist hopes it will change; the realist adjusts the sail |
Posted By: Stefan Lloyd
Date Posted: 16 Jan 06 at 8:06pm
| But Hannah, you don't need to be able to handle all the possible pressure on the sails. You can always ease things or pinch. That means you are slower upwind, but a lighter crew/helm is also faster downwind. So the question of what the optimum crew weight is depends on how much slower upwind versus how much quicker downwind, which is not at all simple to work out from a theorectical perspective. |
Posted By: gordon
Date Posted: 17 Jan 06 at 10:42am
|
Optimum weight is always about 10 kilos less than I can get down to before the next event !
Gordon ------------- Gordon |
Posted By: jeffers
Date Posted: 17 Jan 06 at 11:05am
If anyone has had the pleasure of a training session with Adam Bowers he explains it quite well. He uses the concept on 'units' These are completely arbitrary and vary from sailor to sailor and from boat to boat. Basicaly when you are at 20 units the boat is fully powered, you are fully hiked and the boat is going the fastest that is possibly can on the given point of sail. If you have less than 20 units you should be trying to power the boat up, using the gust to gain ground etc.. More than 20 units you need to start depoering using vang, cunningham, outhaul and feathering the sails. His way of putting it was that if you have more than 20 units you need to spill the required number of units to bring you back down because you are not going to go any faster! That is a very very brief summary of a 2 hour or so talk about it. Paul ------------- Paul ---------------------- D-Zero GBR 74 |
Posted By: m_liddell
Date Posted: 17 Jan 06 at 2:16pm
| There are other factors that play a big part, like how much the rig can be de-powered and the mast stiffness etc. |