Laser 28 - Excellent example of this great design Hamble le rice |
![]() |
Rossiter Pintail Mortagne sur Gironde, near Bordeaux |
![]() |
List classes of boat for sale |
Weight equalisation |
Post Reply ![]() |
Page <1 10111213> |
Author | |
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() Posted: 04 Jan 22 at 11:56am |
Yes, exactly what I was planning to do, have even got a set of warehouse scales to set it all up on. Just need to set it up with a model helm that won't shut up moaning all the time. ![]() |
|
![]() |
|
2547 ![]() Really should get out more ![]() Joined: 11 Aug 11 Online Status: Offline Posts: 1151 |
![]() ![]() ![]() ![]() |
Well I have missed a lot since starting this topic ... I wasn't really expecting to see some people trying to rewrite the laws of physics but I should have expected that.
Anyway ... seems the answer to my original question is that weight equalisation in dinghy sailing is a concept that is almost forgotten bar a few classes in the UK. |
|
![]() |
|
ChrisI ![]() Posting king ![]() ![]() Joined: 09 Aug 10 Location: United Kingdom Online Status: Offline Posts: 143 |
![]() ![]() ![]() ![]() |
PS Very interesting data analysis on the RS800 from Mozzy... many thanks.
|
|
![]() |
|
Sam.Spoons ![]() Really should get out more ![]() Joined: 07 Mar 12 Location: Manchester UK Online Status: Offline Posts: 3400 |
![]() ![]() ![]() ![]() |
I'm guessing it's 'cos it's never a steady state, windsurfing we'd pump a couple of times in a gust to get over the hump, the act of extending to windward to counterbalance a slight increase in wind strength will have a similar effect if you are on the point of planing anyway. Once you are planing there is less boat in the water thus less drag so you don't need as much power to keep planing as you did to get planing. I agree WRT the wide/FW idea, I think boats are not so different to windsurfers when it comes to the effects of rocker and planing areas and the basic concepts, that wide flat planing areas get going sooner than narrow/curvy ones is easy to see as is the trade off that wide flat boats are slower in displacement mode.
|
|
Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish" |
|
![]() |
|
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() |
Which still gets back to the original question, what's best to achieve that high or low hook?
![]() |
|
![]() |
|
423zero ![]() Really should get out more ![]() Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 3420 |
![]() ![]() ![]() ![]() |
Griff, what do you make of the 'dead downwind speed' thing? Thought you would be all over that.
|
|
Robert
|
|
![]() |
|
fab100 ![]() Really should get out more ![]() ![]() Joined: 15 Mar 11 Online Status: Offline Posts: 1005 |
![]() ![]() ![]() ![]() |
Mozzy’s et al have told you, pay attention - hook should be just above your CoG. If you want more righting moment you need to trapeze low, perpendicular to the mast with the boat absolutely flat as that moves your CoG out marginally further. And be out in your tippy-toes, and in platform boots in your case. Which all works as long as you are not crashing into waves, obvs. As usual, the moral is that if you’d learn to apply accepted best practice, you’d gain far more on the water than by trying to invent new tricks that aren’t there. Interesting thread tho; it’s wakened the place up. |
|
![]() |
|
Mozzy ![]() Far too distracted from work ![]() Joined: 21 Apr 20 Online Status: Offline Posts: 209 |
![]() ![]() ![]() ![]() |
oFF, does tension in the wire increase when it's higher up the body? I would have thought it decreased as it will be supporting less of the weight of the sailor.
If the hook was exactly on the CoG and the sailor flat wiring then all the weight would be on the wire. But as that goes higher up the body more weight is supported by the feet. If the hook is below the CoG then tension increases as the feet would have to push up on the gunwale to stop the sailors feet flipping above thier head. It would feel like hiking. You could get almost an infinite amount of tension in the wire by attaching it closer and closer to your feet... if your body didn't give way first. So going back to the tree analogy, you can either get more tension in the wire attaching it lower, but at a less effective angle or less tension at a more effective angle with a higher hook. Thus preserving the same resultant righting moment produced by the sailor no matter where they attach to the wire (we summed in addition to the force on the gunwal / rack). |
|
![]() |
|
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() |
If like me you joined the AYRS which I ran into during my eccentric speed week and revolutionary sail design period, in which I had to develop a sail to allow light weight me to take on heavyweight speed meat heads. You meet all those kind of guys, how to sail dead upwind, perpetual motion devices, although I must admit that device is genius in that it works. I love eccentrics that want to defy the alleged laws of physics, one day someone may find the means to travel faster than light, which I once proved to my physics master at school in theory at least only to be treated with as much derision as I receive here. ![]() Honestly I don't fully understand a lot of what the informed guys have clearly postulated, nobody has adequately explained in a manner that convinces me for instance that a rack and wire achieve the same thing and that need to be disproved. So this theory v mechanics thing aint over for me, there's something missing that I haven't completely grasped, even if you assume the weight transfer goes up the wire, then down the other side via the lee shroud, the leverage is still greater than that same weight being applied to a static rack which might scientifically explain at least why a trapeze is faster. Edited by iGRF - 04 Jan 22 at 7:12pm |
|
![]() |
|
iGRF ![]() Really should get out more ![]() ![]() Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499 |
![]() ![]() ![]() ![]() |
.double post.
Edited by iGRF - 04 Jan 22 at 7:10pm |
|
![]() |
Post Reply ![]() |
Page <1 10111213> |
Forum Jump | Forum Permissions ![]() You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |