New Posts New Posts RSS Feed: Weight equalisation
  FAQ FAQ  Forum Search   Register Register  Login Login

Weight equalisation
 Post Reply Post Reply Page  <1 89101112 13>
Author
  Share Topic Share Topic  Topic Search Topic Search  Topic Options Topic Options
Paramedic View Drop Down
Really should get out more
Really should get out more


Joined: 27 Jan 06
Location: United Kingdom
Online Status: Offline
Posts: 929 		Post Options Post Options   Quote Paramedic Quote  Post ReplyReply Direct Link To This Post Topic: Weight equalisation
    Posted: 03 Jan 22 at 8:13am
Originally posted by Oatsandbeans

Exactly right-the only thing that matters for the righting moment is the distance from the centre line to the centre of mass of the sailor. You don’t have to think about anything else it will just confuse your thinking (a bit like the lee bow effect conundrum!)

So if you aren't pulling on the mast why does the windward shroud go slack in marginal trapezing conditions?

The effect may be negligible but there simply must be one beyond positioning the body further out.
Back to Top
Paramedic View Drop Down
Really should get out more
Really should get out more


Joined: 27 Jan 06
Location: United Kingdom
Online Status: Offline
Posts: 929 		Post Options Post Options   Quote Paramedic Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 22 at 8:06am
So:

If the height of the wire on the mast makes no difference why bother with a trapeze at all?

If the angle of the wire to the body (Position of the wire on the body effectively) doesn't make a difference why not just trapeze off the centreboard case all of the time and reduce your windage?

A higher hook on the body must make a difference but isn't practical and probably doesn't make enough difference to make the impracticalities worth dealing with.


Edited by Paramedic - 03 Jan 22 at 8:07am
Back to Top
Oatsandbeans View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 19 Sep 05
Location: United Kingdom
Online Status: Offline
Posts: 382 		Post Options Post Options   Quote Oatsandbeans Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 22 at 8:01am
Exactly right-the only thing that matters for the righting moment is the distance from the centre line to the centre of mass of the sailor. You don’t have to think about anything else it will just confuse your thinking (a bit like the lee bow effect conundrum!)
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: 03 Jan 22 at 7:03am
If you move the hook position higher up your body, I think you’d risk damaging your back.  
Also, with a high hook on the harness, in a lull where you’d sit up in the harness (and/or bend your knees) your ass would end up in the water, especially on a Contender with low freeboard.

(iGRF - Have you got any pictures of your Contender to post on here yet?)
Back to Top
ohFFsake View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 04 Sep 08
Location: United Kingdom
Online Status: Offline
Posts: 219 		Post Options Post Options   Quote ohFFsake Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 22 at 1:35am
Originally posted by iGRF

Originally posted by 423zero

Imagine lying on a plank with no wire, you would still have same effect.


I don't think so, a plank surely is applying the moment through the hull.

A wire is using the additional leverage of the mast height.

Having a higher hook wouldn't that be like sitting further out on the plank?

The plank acts like a lever, but is shorter and lower down, say what 2-3 mtrs?

Doesn't The trapeze wire transfer the weight application to the mast, which in turn levers the boat, or at least counters the sail pressure, the mast is what 5 mtrs?

Someone clever needs to do the maths and prove it to me.

Because all my instincts tell me to use a higher hook.
Sorry, but your instincts is all wrong!

In terms of applying righting moment the use of the mast is entirely incidental. It's there to hang the sails on which happens to make it a convenient place to hook a trapeze to but that's as far as it goes. Once you are hooked on you are just part of a static system in equilibrium, and as someone else pointed out you would have the exact same righting moment if you were lying on a plank.

The only thing that affects your righting moment is how far away from the centreline your body mass is, and altering the position of your hook doesn't change that. 
Back to Top
423zero View Drop Down
Really should get out more
Really should get out more


Joined: 08 Jan 15
Location: United Kingdom
Online Status: Offline
Posts: 3420 		Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 22 at 12:00am
You are thinking about pulling the boat over if you were standing on the ground, the higher the rope the more leverage you have. When trapezing and you are horizontal, height of cable makes no difference, you are ten stone on a plank and ten stone when using wire and core strength to stay out flat.
Robert
Back to Top
iGRF View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 07 Mar 11
Location: Hythe
Online Status: Offline
Posts: 6499 		Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 22 at 11:52pm
Originally posted by 423zero

Imagine lying on a plank with no wire, you would still have same effect.


I don't think so, a plank surely is applying the moment through the hull.

A wire is using the additional leverage of the mast height.

Having a higher hook wouldn't that be like sitting further out on the plank?

The plank acts like a lever, but is shorter and lower down, say what 2-3 mtrs?

Doesn't The trapeze wire transfer the weight application to the mast, which in turn levers the boat, or at least counters the sail pressure, the mast is what 5 mtrs?

Someone clever needs to do the maths and prove it to me.

Because all my instincts tell me to use a higher hook.

Edited by iGRF - 02 Jan 22 at 11:55pm
Snow Equipment Deals    New Core Kite website
Back to Top
Grumpycat View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 29 Sep 20
Online Status: Offline
Posts: 497 		Post Options Post Options   Quote Grumpycat Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 22 at 11:42pm
Originally posted by Rupert

Maybe just tie it round the neck?

Love your logic,Rupert  LOL
Back to Top
423zero View Drop Down
Really should get out more
Really should get out more


Joined: 08 Jan 15
Location: United Kingdom
Online Status: Offline
Posts: 3420 		Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 22 at 11:41pm
Imagine lying on a plank with no wire, you would still have same effect.
Robert
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: 02 Jan 22 at 10:53pm
Gawd bless you Tink for even trying. 
Back to Top
 Post Reply Post Reply Page  <1 89101112 13>

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