Guys - I think I've missed a trick, having only sailed in very heavy weather so far. So I rig the boat, set off, get on the first beat and notice the boom is way out despite the mainsheet being in as far as possible. Obviously the traveller blocks aren't centralised which I guess would solve the problem. Do I sit onshore and bang as much vang on as I can before setting off to sort this problem out, or is there another trick that has passed me by?
Upwind and the traveller
- Thread starter Mobman
- Start date
Rob B
Well-Known Member
Is the trim "2 blocked" on the corner of the transom? That is the block on the end of the boom and the block on the traveler are touching? Is the traveler pulled down flush to the deck?
49208
Tentmaker
The trav blocks should be right out at the edge of the hull for most conditions except specific light air/drifting and even in those conditions, they are never in more then 4 inches or so from the edge...
Check the slack on the traveler line...
cbyc_radial_sailor
New Member
yeah.. what pez said... you have to put a TON of pressure on the traveller.
Cheers for that, all. The two blocks are up against one another, the traveller is fairly close to the deck but no doubt could be closer, I'll bang some tension on. I was just concerned that in the sort of dinghies I've been racing, you're making every attempt to get that boom as close to the centreline as you can, but the Laser boom is 5, maybe even eight degrees away from that "nearly close" alignment and my fear was that I was paying for it in pointing ability. Sounds like everyone's paying the same price though.
49208
Tentmaker
Most "mainsail only" dinghys need to have the boom off the corner of the transom or further out. Keeping it anywhere near centerline just causes a huge drop in speed, which causes the blades to generate just a fraction of the lift they are capable of.
If you compare mains between a single sail rig and a jib rigged boat, the mains are not "seeing" the same wind angle. The jib forces the air to bend around it, in effect providing a constant lift to the main. This is one of the reasons why you can get the boom on centerline or above.
If you compare mains between a single sail rig and a jib rigged boat, the mains are not "seeing" the same wind angle. The jib forces the air to bend around it, in effect providing a constant lift to the main. This is one of the reasons why you can get the boom on centerline or above.
Actualy, it's not true that the jib bends the air around the mainsail.
In reality it's actualy the mainsail stoping up wind and pushing it in so the jib gets alot more power.
The missconception that the jib would give the main extra power is very widespread but quite wrong. There are books on the matter (where they've been doing wind tunnel testing and stuff like that), sadly don't remember the names of them though.
In reality it's actualy the mainsail stoping up wind and pushing it in so the jib gets alot more power.
The missconception that the jib would give the main extra power is very widespread but quite wrong. There are books on the matter (where they've been doing wind tunnel testing and stuff like that), sadly don't remember the names of them though.
GeoffS
Member
C. A. Marchaj and Arvel Gentry
Gentry's classic paper on the topic is The Aerodynamics of Sail Interaction.
Marchaj's latest book on the topic is Sail Performance : Techniques to Maximize Sail Power.
Cheers,
Geoff S.
49208
Tentmaker
Thanks for the links -
My sentence above should be changed to header instead of lift:
"The jib forces the air to bend around it, in effect providing a relative header to the main"
Obviously it's not a simple subject with more then one cause and effect from having the jib in front of the main
My sentence above should be changed to header instead of lift:
"The jib forces the air to bend around it, in effect providing a relative header to the main"
Obviously it's not a simple subject with more then one cause and effect from having the jib in front of the main
