Boom up = nose up

[Wing 11]

We all know from practice that higher boom lift nose up.

Every time I thinking about this I have confusion.

When we put boom up,harness lines stay more vertical so we can transfer more weight on sail ,therefore mast foot pressure(MFP) also increase.
Bigger MFP must hold nose down..

Can someone explain why than boom up lift nose up ?

[basher]

A higher boom doesn't lift my board's nose up. It just makes my arms tired sooner and stops me waveriding. I like the boom in front of me.

The accepted theory of the higher boom is directed at beginners and intermediates to help them get weight off the fin.
The theory is that hanging off a higher boom increases mast foot pressure, and reduces sailor weight acting on the tail. That in turn helps you keep the board flat, so in theory it LOWERS the nose, not raises it.

In practice you can increase mast foot pressure without raising your boom – simply by leaning forwards more, and by adding a more downward component to the way you load up the rig via your harness lines.

As far as levelling the board goes the best way to do that is to move forwards to lower the nose and to move back to raise it. So board 'trim' (as we call this) is best determined by shifting weight on the board, moving the footstrap positions if necessary.

Preferred boom height is also linked to mast foot position and in theory you should think about changing boom height if you shift the mast foot.

[max111]

We all know from practice that higher boom lift nose up.

Every time I thinking about this I have confusion.

When we put boom up,harness lines stay more vertical so we can transfer more weight on sail ,therefore mast foot pressure(MFP) also increase.
Bigger MFP must hold nose down..

Can someone explain why than boom up lift nose up ?

You may have raised it to high and the weight may be on your back foot now ? This will alter the boards trim in the water and stop you planing

[basher]

I think Klaus Voget is wrong on a lot of stuff there.
I saw that video before and I found a lot of the advice a bit dodgy.

In this case, changing boom height does very little to alter the amount of sail above the boom (as he claims here). Even if it did, how would it affect the for-and-aft trim of the board?

Anyone else wanna comment on this?


The advice for beginners and intermediates is as I have already explained.
Once you know what you are doing, then boom height in wave kit is about what is comfortable for your height. At that point you might raise the boom a bit to help jumping or lower the boom to help with wave riding. Some wave riders still like a higher boom to help them project off the lip, but a lower boom is often preferred by those wanting to get over the rig in a cranked bottom turn.

In slalom, boom height is more linked to the mast foot position, which in turn is about gaining control over the rig and fin.

[rod]

High boom takes weight of the board and helps with early planing in light winds. In stronger winds a lower boom helps you get lower and more weight over the board giving more control.

People wave ride ride well with either set up. (In the PWA final there were a variety of boom heights extensively commented on).

[basher]

.....this has nothing with MFP...

Problem is every pro PWA sailors say in videos that thay lower boom in stronger winds to stay board flat,put nose down..AA,Bjorn,Sebastian Kornum,Peter Bijl etc...

And this is not logical to me..
......

Well, in fairness, that video is about different settings for different height sailors. I still think they get it wrong though.


If talking about pro sailor advice then we need to separate what sort of sailing they are doing.
There's probably one way of describing things for slalom sailors and another way that wave sailors think about these things.

However, both wave sailors and slalom sailors tend to agree that we use a lower boom when the conditions get rough. That lower boom tends to do two things:
One, it gets the rig in front of you, making it more controllable than if it's over your head.
Two, it tends to mean you have less mast foot pressure and more weight on the tail of the board, giving you more control over the fin. If you are well powered up, then more weight on the tail is counteracting the rig load better, so it doesn't necessarily mean the board is riding high at the nose.

In light or strong winds you still want the board flat. A level board is faster – and the faster you go the more the pressure is released in the sail. We only actually want to raise the nose as much as is necessary to go over waves and chop without stopping.


In slalom, it gets a bit more complicated because the board is ridden off the fin more. So to regain control in windy weather you might want to shift the mast foot forwards a bit, to increase the distance from mast foot to fin, and that lowers the boom for you. So a slalom sailor might actually raise the boom a bit to suit the new mast foot position.

[Gorgesailor]

Klaus is defintily wrong,this has nothing with MFP...

Problem is every pro PWA sailors say in videos that thay lower boom in stronger winds to stay board flat,put nose down..AA,Bjorn,Sebastian Kornum,Peter Bijl etc...

And this is not logical to me..

Yes, don't listen to them. They are all idiots...carry on as you are & see how far logic gets you.